18-102691.� 8-102- 69
CITY OF
Federal Way
April 12, 2019
Mr. Pat Hopper
Barghausen Consulting Engineers, Inc.
18215 72nd Ave S
Kent, WA 98032
CITY HALL
33325 8th Avenue South
Federal Way, WA 98003-6325
(253) 835-7000
www.cityoffederalway.com
Jim Ferrell, Mayor
RE: Impact Fee Credit for Frontage Improvement and Right -of -Way (ROW) Dedication on
16th Ave S
Dear Mr. Hopper:
The City of Federal Way has reviewed your Impact Fee Credit request dated March 12, 2019.
After evaluating your request, reviewing of Federal Way Revised Code (FWRC) provisions
(Section 19.91.090), and the direction provided by the City Council, the Public Works
Department provides the following response to your request.
Federal Way Revised Code (FWRC) Section 19.91.090 outlines criteria when the impact fees
credit would be awarded for the total value of system improvements, including dedications of
land, improvements and/or construction provided by the applicant. Staff has reviewed the
criteria, and determined that the frontage improvements and right-of-way dedication on 16th
Avenue S would qualify for impact fee credit under FINRC section 19.91.090(1)(a). The frontage
improvement is listed in the rate study as "SR 18 @ SR 161: Add V SB thru lane, 3rd SB left -turn
lane, 2"d NB right -turn lane".
A legal description of the dedicated land is as specified below:
EXHIBIT A
(Right -of -Way Dedication)
A portion of Parcel A, City of Federal Way Boundary Line Adjustment No. 18-101374-00-SU, in
Book 388 of Surveys, Pages 294-296, under recording number 20180731900008, Records of
King County, Washington, being a portion of Lots 19 and 22, Vick Addition, according to the plat
thereof recorded in Volume 45 of Plats, page 27, in King County, Washington, lying in the
Northeast Quarter of the Southeast Quarter of Section 20, Township 21 North, Range 4 East,
W.M., King County, Washington, more particularly described as follows:
BEGINNING at the southeast corner of said Parcel A, being a point 42.00 feet west of the east
line of the Southeast Quarter of said Section 20 and 30.00 feet north of the south line of the
Northeast Quarter of the Southeast Quarter of said Section 20;
I:\Jacksons 16 Ave 5 TIF Credit.docx
THENCE North 01'34'18" East, along the westerly margin of 16th Avenue South and parallel with
said east line of the Southeast Quarter a distance of 158.11 feet to the north line of said Lot 22;
THENCE North 88°39'09" West, along the north line of said Lot 22 a distance of 8.00 feet;
THENCE North 01'34'18" East, a distance of 79.05 feet to the north line of said Lot 19;
THENCE North 88°39'09" West, a distance of 10.00 feet;
THENCE South 01 °34'18" West, a distance of 212.26 feet to a point of curvature to the right
having a radius of 25.00 feet;
THENCE Southwesterly along the arc, through a central angle of 89°46'33", a distance of 39.17
feet to a point on the northerly margin of South 348th Street;
THENCE South 88°39'09" East, along said northerly margin a distance of 42.90 feet to the POINT
OF BEGINNING.
FWRC section 19.91.090(4) authorizes the Public Works Director to determine the value of the
dedicated land and improvements [if applicable]. Based on the submitted Engineers Cost
Estimate and King County Assessor's records, the dedicated land is valued at $78,659.00. The
Public Works Director hereby grants the applicant a credit in the amount of $37,858.90 to be
applied toward the traffic impact fees for the Jackson Food Store/Gas Station project (File Nos.
17-105138-00-UP & 17-105139-00-SE), which is estimated at $37,858.90. Please note, since the
credit for the land dedication exceeds the amount of the traffic impact fee obligation, the
developer will not be entitled to reimbursement of the difference.
Should you have any questions, please do not hesitate to contact Sarady Long, Senior
Transportation Planning Engineer, at (253) 835-2743.
Sincerely,
EJ �alsh, P.E.
Public Works Director
EJ/SL:ss
M Project File (ce)
Day File
I:\Jacksons 16 Ave 5 TIF Credit.docx
EXHIBIT A
(Right -of -Way Dedication)
A portion of Parcel A, City of Federal Way Boundary Line Adjustment No. 18-101374-00-SU, in Book 388
of Surveys, Pages 294-296, under recording number 20180731900008, Records of King County,
Washington, being a portion of Lots 19 and 22, Vick Addition, according to the plat thereof recorded in
Volume 45 of Plats, page 27, in King County, Washington, lying in the Northeast Quarter of the
Southeast Quarter of Section 20, Township 21 North, Range 4 East, W.M., King County, Washington,
more particularly described as follows:
BEGINNING at the southeast corner of said Parcel A, being a point 42.00 feet west of the east line of the
Southeast Quarter of said Section 20 and 30.00 feet north of the south line of the Northeast Quarter of
the Southeast Quarter of said Section 20;
THENCE North 01*34'18" East, along the westerly margin of 161h Avenue South and parallel with said
east line of the Southeast Quarter a distance of 158.11 feet to the north line of said Lot 22;
THENCE North 88'39'09" West, along the north line of said Lot 22 a distance of 8.00 feet;
THENCE North 01°34'18" East, a distance of 79.05 feet to the north line of said Lot 19;
THENCE North 88°39'09" West, a distance of 10.00 feet;
THENCE South 01°34'18" West, a distance of 212.26 feet to a point of curvature to the right having a
radius of 25.00 feet;
THENCE Southwesterly along the arc, through a central angle of 89°46'33", a distance of 39.17 feet to a
point on the northerly margin of South 348th Street;
THENCE South 88°39'09" East, along said northerly margin a distance of 42.90 feet to the POINT OF
BEGINNING.
(Containing 3,769± square feet)
Project: 17764 FW Jacksons
17764L.002.doc
OBH
October 25, 2018
EXHIBIT B
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8 3QTH ST S88'39'09"E
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42.90'
(SOUTH
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—
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PTN. OF NE114 OF THE SE114 SECTION 20,
SCALE:
HORIZONTAL 1 "=50' VERTICAL N/A
G H A U 18215 72ND AVENUE SOUTH
KENT WA 98032
m Z (425)251=6222
_ o (425)251-8782 FAX
a � �
s� ? CIVIL ENGINEERING, LAND
°�, ►��as. PLANNING, SURVEYING,
ewc s+ti ENVIRONMENTAL SERVICES
DRAWN OBH
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ai
T21 N, R4E, W.M. u-_
For: JOB NUMBER
CITY OF FEDERAL WAY 17764
17764L. 002. DOC
Title: SHEET
RIGHT-OF-WAY
DEDICATION 1 of 1
BOND QUANTITIES WORKSHEET
ect Name: Jacksons #636
No.: BCE#17764
Site Address: 1520 S 348th Street Federal Way, WA 98003
Fill in those items which pertain to this project and return to the
Public Works Department.
GENERAL CONSTRUCTION
Backfill & Compaction- embankment
8 CY
Backfill & Compaction -trench
11 CY
Clear/Remove Brush, by hand
2363 Acre
Clearing/Grubbing/Tree Removal
13000 Acre
Excavation - bulk
2.5 CY
Excavation -Trench
5 CY
Fencing, chain link, vinyl coated, 6' high
18 LF
Fencing, chain link, gate, vinyl coated, 20'
1563 Each
Fill & compact - common barrow
27 CY
Fill & compact -gravel base
30 CY
Fill & compact - screened topsoil
62 CY
Grading, fine, by hand
2 SY
Grading, fine, with grader
1.25 SY
Monuments with case, 18" long
104 Each
Sensitive Areas Sign
20 Each
Pond Sign
100 Each
Sodding, 1" deep, sloped ground
10 SY
Topsoil Type A (imported)
30 CY
Surveying, line & grade
850 Day
Surveying, lot location/lines
1800 Acre
Traffic control crew ( 2 flaggers) -
98 HR
Trail, 4" chipped wood
9 SY
Trail, 4" top course
9.5 SY
Wall, retaining, concrete
66 SF
Wall, rockery
13 SF
SUBTOTAL
Public Roadway Future Right -of -
Improvements Way Improvemerr
T $0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
450
$1,125.00
L $0.00
110
$550.001
$0.00
615
$11,070.00
$0.00
$0.00
$0.00
50
$1,350.00
$0.00
10
$300.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
$0.00
$0.001
$0.00
$0.00
$0.00
$0.00
$0.00
400
$4,000.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$ 18,395.00 $ -
STREET IMPROVEMENT
AC Grinding, 4' wide machine < 1000sy
AC Grinding, 4' wide machine 1000-2000sy
AC Grinding, 4' wide machine> 2000sy
AC Removal/Disposal
Barricade, type III ( Permanent )
Curb & Gutter, vertical
Curb and Gutter, demolition and disposal
Curb, extruded concrete
Sawcut, asphalt, 3" depth
Sawcut, concrete, per 1" depth
Sealant, asphalt
Shoulder, AC, ( see AC road unit price }
Shoulder, gravel, 4" thick
Sidewalk, 4" thick
Sidewalk, 4" thick, demolition and disposal
Sidewalk, 6" thick (Round -about, Cul-de-Sac)
Sidewalk, 6" thick, demolition and disposal
Sign, handicap
Sign, roadway
Striping, thermoplastic, ( for crosswalk)
Striping, 4" reflectorized line
STREET SURFACING
Additional 2.5" Crushed Surfacing
HMA 1/2" Overlay, 1.5" deep
HMA 1/2" Overlay 2" deep
HMA Road, 0.25', 8" rock, First 2500 SY
HMA Road, 0.25', 8" rock, Qty. over 2500 SY
HMA Road, 0.30', 9" Rock, First 2500 SY
HMA Road, 0.3', 9" Rock, Qty Over 2500 SY
HMA Road 0.30', 0.50 ATB, First 2500 SY
HMA Road 0.30', 0.50 ATB, Over 2500 SY
HMA Road, 0.50', 0.50 ATB, First 2500 SY
HMA Road, 0.50', 0.50 ATB, Over 2500 SY
HMA Road, 0.30', 0.85' Class E & 0.50 CSTC
HMA 3/4" or 1", 4" Depth
Gravel Road, 4" rock, First 2500 SY
Gravel Road, 4" rock, Qty. over 2500 SY
Gravel Road, 4" rock, First 2500 SY
Gravel Road, 4" rock, Qty. over 2500 SY
Thickened Edge
35 SY
8.5 SY
2.5 SY
60 SY
55 LF
15 LF
20 LF
4.5 LF
3.5 LF
3 LF
2 LF
0 SY
11 SY
40 SY
36 SY
45 SY
45 SY
100 Each
350 Each
3.5 SF
0.4 LF
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
300
$18,000.00
$0.00
$0.00
$0.00
400
$6,000.00
$0.00
460
$9,200.00
$0.00
$0.00
$0.00
800
$2,800.00
$0.00
$0.00
$0.00
490
$980.00
$0.00
$0.00
$0.00
$0.00
$0.00
360
$14,400.00
$0.00
345
$12,420.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
200
$80.00
$0.00
SUBTOTAL $ 63,880.00 $ -
(4' Rock = 2.5 bass & 1.5` Gap course) 9 1j2' Rock- 9' base & 1.5' tap course)
6 SY
14 SY
18 SY
28 SY
21 SY
42 SY
35 SY
33 SY
30 SY
45 SY
42 SY
55 SY
20 SY
15 SY
10 SY
15 SY
10 SY
11 LF
SUBTOTAL
$0.00
f $0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
470
$19,740.00
$0.00
$0.00
$0.00
$0.00
.$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
470
$9,400.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$ 29,140.00 $ -
DRAINAGE (CPP = Corrugated Plastic Pipe, N12 or Equivalett For Culvert prices. Average &4f cover was assurnei
Access Road, R/D
26 SY
Bollards - fixed
240.74 Each
Bollards - removable
452.34 Each
* (CBs include frame and lid)
Beehive
90 Each
CB Type
1650 Each
CB Type IL
1850 Each
CB Type II, 48" diameter
2550 Each
for additional depth over 4'
650 FT
CB Type II, 54" diameter
2700 Each
for additional depth over 4'
600 FT
CB Type II, 60" diameter
2900 Each
for additional depth over 4'
750 FT
CB Type II, 72" diameter
4000 Each
for additional depth over 4'
900 FT
Through -curb inlet Framework (Add)
550 Each
Cleanout, PVC, 6"
250 Each
Cleanout, PVC, 8"
300 Each
Roof Drain, PVC, 6"
17 LF
Storm Main, ADS N-12, 8"
25 LF
Storm Main, ADS N-12, 12"
30 LF
Storm Main, ADS N-12, 15"
35 LF
Storm Main, ADS N-12, 18"
45 LF
Storm Main, ADS N-12, 24"
55 LF
SUBTOTAL
--
Culvert, Concrete, 8"
36 LF
Culvert, Concrete, 12"
43 LF
Culvert, Concrete, 15"
52 LF
Culvert, Concrete, 18"
55 LF
Culvert, Concrete, 24"
85 LF
Ditching
12 CY
Flow Dispersal Trench (1,436 base+)
40 LF
French Drain (3'depth)
39 LF
Geotextile, laid in trench, polypropylene
5 SY
Mid -tank Access Riser, 48" dia, 6' deep
2025 Each
Pond Overflow Spillway
18 SY
Restrictor/Oil Separator, 12"
1500 Each
Restrictor/Oil Separator, 15"
1550 Each
Restrictor/Oil Separator, 18"
1680 Each
Riprap, placed
52 CY
Tank End Reducer (36" diameter)
1280 Each
Trash Rack, 12"
320 Each
Trash Rack, 15"
325 Each
Trash Rack, 18"
350 Each
Trash Rack, 21"
375 Each
$0.00
$0.00
$0.00
$0.00
$0.00
1
$0.00
$0.00
$0.00
2
$3,300.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
20
$600.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
1 $0.00
$ 3,900.00 $
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
$0.00
$0.001
$0.00
SUBTOTAL $ - $
UTILITY PALES & STREET LIGHTING
Utility Pole(s) Relocation
Street Light Poles w/Luminaires
Traffic Signal and Appurtenances
Rectangular Rapid Flashing Beacon (RRFB)
LANDSCAPING 8L VEGITATION
Street Trees
Median Landscaping
Right -of -Way Landscaping
Wetland Landscaping
WRITE -IN -ITEMS
(Such as detention/water quality vaults.)
Stormwater Quality Vault
Block Wall
Yard Drain
Utility pole relocation costs must be accompanied by Franchise Utility's Cost.
Lump Sum
10000 Each 4 $40,000.00
Bid Price
Bid Price
500 Each
LS
1 LS
1 LS
380000 Each
16 SY
225 CY
LF
FT
SUBTOTAL:
51
$2,500.001
$0.00
$0.00.
$0.00
40001
$4,000.001
$0.00
12001
$1,200.001
$0.00
$0.00:
$0.00
$0.0&
$0.00
$0.00`
$0.00
$0.00 1
$0.00
50.001
$0.00
$0.001
$0.00
$0.001
$0.00
$0.00 1
$0.00
$0.00!
$0.00
$0.00 i
$0.00
(A) $ 47,700.00 (B) $
TOTAL: (A) 163015 (B)
The following information will be completed by the City of Federal Way Public Works Department:
EXISITNG PUBLIC ROADWAY IMPROVEMENTS (Total A): $
FUTURE PUBLIC ROADWAY IMPROVEMENTS (Total B): $
EROSION/SEDIMENT CONTROL (Total C): $
SUBTOTAL (A + B + C): b
30% CONTINGENCY & MOBILIZATION: $
TOTAL BOND AMOUNT: $
0
EROSION/SEDIMENT CONTROL WORKSHEET
Project Name: Jacksons #636
Project No.: BCE#17764
Site Address: 1520 S 348th Street
Unit
# of
Reference #
Price Unit
Qty App.
Cost
EROSION/SEDIMENT CONTROL
Backfill & compaction -embankment
6.5 CY
0
Check dams, 4" minus rock
SWDM 5.4.6.3
78 Each
Crushed surfacing 1 1/4" minus
WSDOT 9-03.9(3
98 CY
50
4900
Ditching
8 CY
Excavation -bulk
3 CY
600
1800
Fence, silt
SWDM 5.4.3.1
2 LF
780
1560
Fence, Temporary (NGPE)
2 LF
0
Hydroseeding
SWDM 5.4.2.4
1 SY
50
50
Jute Mesh
SWDM 5.4.2.2
2 SY
0
Mulch, by hand, straw, 3" deep
SWDM 5:4.2.1
3 SY
0
Mulch, by machine, straw, 2" deep
SWDM 5.4.2.1
1 SY
0
Piping, temporary, CPP, 6"
12.5 LF
0
Piping, temporary, CPP, 8"
19 LF
0
Piping, temporary, CPP, 12"
24 LF
0
Plastic covering, 6mm thick, sandbagged
SWDM 5.4.2.3
3 SY
100
300
Rip Rap, machine placed; slopes
WSDOT 9-13.1(2
50 CY
0
Rock Construction Entrance, 50'x15'x1'
SWDM 5.4.4.1
1800 Each
Rock Construction Entrance, 100'x15'x1'
SWDM 5.4.4.1
3600 Each
1
3600
Sediment pond riser assembly
SWDM 5.4.5.2
`3050 Each
Sediment trap, 5' high berm
SWDM 5.4.5.1
21 LF
110
2310
Sed. trap, 5' high, riprapped spillway berm
SWDM 5.4.5.1
79 LF
0
Seeding, by hand
SWDM 5.4.2.4
1 SY
0
Sodding, 1" deep, level ground
SWDM 5.4.2.5
8 SY
0
Sodding, 1" deep, sloped ground
SWDM 5.4.2.5
9.5 SY
0
TESC Supervisor
84 HR
0
Water truck, dust control
SWDM 5.4.7
130 HR
0
WRITE -IN -ITEMS
Each
0
0
0
ESC SUBTOTAL
14520
30% CONTINGI
4356
ESC TOTAL:
18876
r�
CITY OF
Federal Way
Centered on Opportunryy
2019 Traffic Impact Fees 2019
Scroll down and complete the steps outlined below: Please fill in the required information in the yellow highlighted
boxes.
STEP #1: General Information
Enter the following information
Project Name Jackson Food Store/Gas Station
File Number 17-105138-UP
Street Address
City, State Zip 1520 S 348th St
Parcel Number (s) 889700-0115
Traffic Impact Fee Estimated By SL
Is this project locate within the City Center Zone? If "YES", please use City Center Impact Fee sheet.
STEP #2: Land Use Type
Select the proposed Land Use Type(s) from the drop down memu below. Enter the proposed number of units for
the Project
Unit of
Number of
Impact Fee Rate per
Preliminary Impact
Proposed Land Use Type (s)
Measure
Unit(s)
Unit of Measure
Fee Amount
1) Super Conv Market/Gas Station
sf/GFA
3486
$ 39.93
$ 139,204.65
2) Warehousing
sf/GFA
1910
$ 1.45
$ 2,763.07
3) NONE
N/A
$ -
$ -
4) NONE
N/A
$
$ -
$ 141,967.72
4/4/2019 King County Department of Assessments: eReal Property
F
ADVERTISEMENT
Parcel 839700-0090
Number
Name TURNER. TOM+LYNNE—TE
Site Address '34703 !CTH AVE S 98003
Legal DICK ADO LOT 18 LESS ELY 12 ;-T--I—'Y OF F-DERAL WAY ORDINANCE '--0 DPJM,\Y
29, 1991
Year Built 1974
Building Net Square Footage 2400
construction Class
PREFAB STEEL
Building Quality
LOMAVERAGE
Lot Size
22585
Present Use
Retail Store
Views
NO
Waterfront
Year:Tax 2019 Levy Code: 1205 Total Levy Rate: $11.24291 Total Sensor Rate: 16.46333
46.681% Voter Approved
Ciick here to see lever distribution comparison Lby year.
Valued Tax Appraised Land Appraised Imps Appraised Appraised Imps Taxable Land Taxable Imps Taxable
Year
Year Value
Value
Total (5)
: Increase (S)
value j53
Value
Total
21718
2019 J06,500
i59.50
566,00I-1
0 v
406.500
r'59.501)
5166,000
2017
s9018 338... 75n
200,0010
5!38,700
0
338 7 0 0,
200,000
538.700
2016
2-0017 338,700
200.000
0
338.700
200,000
538,700
2015
2016 271.0O0
'207.800
478,6110
0
.271,000
207.600
478,60D
414
201 F 271,000
2k,7.F,,0
4786i;()
0
271.000
207:600,
478,600
20'13
)'I 4 271,0r,�)
V 2 16. 7 00)
43-7,700
2 1 �..70(',
487,701)
21012
2013 271,000
i95.100
4 6 b,! f 0-0
0
271.000,
'9C,100
6 '1', "1' -0 0
2011,
20-12 271,000
470.60^
0
27 000
170.600
441 , GO , 0
2010
2011 271,000
72 4 0 .0,
443,400
271.000)
72,400
43. A 0 0
2009
2 010, 271.000
5 4. [1) 0,
425,000
0
271.11,00
b4000
d25,0-,,',0
'008
2009 27 1 0 0 f-I
9 2 � 4 0 -0
�6 3, 4 0 0
11
271i"00
92. Jr,
163,400
2007
2 00 -1 271,00;
1 r,2 400
J'
0 0 ej
92.-I00
463,400
2006
•2007 1 '1 16 0 u
2 4 4.: 0 0
425,200
j
24A.600
12 5, 2! 1 0
20 G, 11
200& 158,000
2 2 C.. 5, 0 0
0
1.58,00v
226.010
38 500
hftps://blue.kingeounty.com/Assessor/eRealProperty/Dashboard.aspx?ParcelNbr=8897000090
ADVERTISEMENT
1/2
4/4/2019 King County Department of Assessments: eReal Property
F
ADVERTISEMENT
Parcel ' 889 1100-0 115
Number
Name PP., C VY E S T ENERGY L LC
Site 520 S 348TH SIT 98003
Address
Legal VICK ADD FCZ' OF FEDERAL WAY BLA, -118- 101374-00-SU REG #20180731900008 SD BLA BEING
POR 0'-- LOTS 19 & 21- 22 OF SG ADD LESS CC RC?
Year Built 1-968
Building Net Square 1078
Footage
Construrtian Class PREFAB STEEL
Building Quality GOOD
Lot Size 4,5699
Present Use Ccry Store '*'ith
Gas
Views No
Waterfront
Tax Year: 2,019 Levy Code: 1205 Total Levy Rate, $11.24291 Total Senior Rate: $6.46333
46,68% Voter Approved
Click here-Lo-see 19 yj:iLtdbu A' ion cam . nrisqn �y-year.
---- ----
Valued, Tax Appraised Land 'Appraised Imps Appraised Appraised imps TaxableLandTaxablelnips Taxable
Year
Year Value
Value (S)
Total (S)
Increase ($I
Value, (Si
Value jS)
Total (S)
2018
2019 988,000
6 2 6. 0 00;
1,614,000
0
9 8 8. 1; 0 .0..
62610 or,
9.'614.00G
20'17
20'M 'K3.600
632200
1,435.800
0
632.200R
!,435.800
2016
2017 A74,40 ;0
973-9010
1,Q4F:30-;
0
474.400.
573 91 0
1,048.30-0
2015
;2016
618.100
1.045,0p0*
0
42(3:9C7';
2014
15 426.9U0
6115,100
1,052J000
0
422 6.9. 0 0
525,100
I , 052,000
2013
2714 379,500
6281900
1,008,400;
a
379:500
6- 2 P- 9 0 0
1,008:400
2012
2 0 13 3 3 2, 000
629, 1; 00
-0
3 3 2. 0 00
6291100
961,100
20111
2012 332,000
639.300
:71'800
0
332,000
339.800
9171,800
2010
2011 '332,000
623,200
956,200
3
332.000
623.200
9 5,15. 2 f 1 0
2009
2fil 1) 332,100
64
7,5, 0 00
0
332 100
'0
2008
'7009 332.100
633.2no
965,300
332. '00
33,200
2007
i 2008 332,100
634-100
9 6 6-, j 0 0
0
332.100
i34,400
91 6 6, L, 0
2006
70 ;07 332,100
617201;
049,300
3
332, i 00
5, 17, 200
349.300
ADVERTISEMENT
' C,
S�,4-jw
2,,reo Sr
https://blue.kingcounty.com/Assessor/eRealProperty/Dashboard.aspx?ParcelNbr=889700011 5 1/2
10PTEN W
Transportation Engineering NorthWest
MEMORANDUM
DATE: March 12, 2019
TO: EJ Walsh
City of Federal Way Public Works Director
FROM: Curtis Chin, P.E.
TENW
SUBJECT: Request for Transportation Impact Fee Credit
Jacksons 636 Federal Way
TENW Protect No. 5679
This memorandum documents a request for transportation impact fee credit associated with the proposed
Jacksons 636 project located at 1520 S 348'h Street on the northwest corner of 16th Avenue S/S 3486
Street in Federal Way, WA.
Background
The project applicant (PacWest Energy LLC dba Jacksons Food Stores, LLC) requests a credit for the
transportation impact fees assessed for the redevelopment of the existing Jacksons Shell Gas station pursuant
to Federal Way Municipal Code 19.91 .090. The frontage improvements to be completed by the project
along 16th Avenue S would be considered system improvements and would be eligible for transportation
impact fee credit. Included in this request for transportation impact fee credit are the following:
➢ A detailed description of the improvement
➢ Legal description of the dedicated land
➢ Cost request
Detailed Description of Improvement
Frontage improvements along 16th Avenue S to be completed by the Jacksons project includes the construction
of a southbound right -turn lane, signal and lighting improvements, construction of a new public sidewalk,
curb, gutter and landscape. These off -site improvements required an 18-foot dedication from the existing
Jacksons site and a 10-foot dedication from their newly acquired north properly. The proposed frontage
improvements would be considered system improvements given they are part of a larger City project as
described below.
The current City of Federal Way 2019 - 2024 Transportation Improvement Plan (TIP) includes TIP Project #9
which includes the addition of a southbound auxiliary lane on 16th Avenue S from S 344th Street to S 348th
Street.
Transportation Planning I Design I Traffic Impact & Operations
1 1400 SE 81h Street, Suite 200, Bellevue, WA 98004 1 Office (425) 889-6747
Jacksons 636 Federal Way
Request for Transportation Impact Fee Credit
Legal Description of Dedicated Land
A legal description of the dedicated land was provided by Barghausen Consulting Engineers and is
included as Attachment A.
Cost Request
The cost request (which does not include the cost of dedicated land) totals $177,535. The detailed cost
estimate as provided by Barghausen Consulting Engineers is provided in Attachment B. As a result, the cost
request far exceeds the City's estimated transportation impact fee of $34,179.37. Therefore, transportation
impact fees for the project should be waived.
If you have any questions regarding the information presented in this memo, please contact me at (425) 250-
5003 or chin@tenw.com.
cc: Caryl Pinner, Barghausen Consulting Engineers
Elyse Stemmler, P.E., TENW
Chris Bicket, P.E., TENW Principal
Attachment
TEN W March 12, 2019
Page 2
Jacksons 636 Federal Way
Request for Transportation Impact Fee Credit
ATTACHMENT A
Legal Description of Dedicated Land
LEGAL DESCRIPTION
A portion of Lots 19, 21 and 22, Vick Addition, according to the plat thereof recorded in Volume 45 of
Plats, page 27, in King County, Washington, lying in the Northeast Quarter of the Southeast Quarter of
Section 20, Township 21 North, Range 4 East, W.M., King County, Washington, more particularly
described as follows:
Lot 19, of Vick Addition, according to the plat thereof recorded in Volume 45 of Plats, page 27, in King
County, Washington;
EXCEPT the East 20 feet thereof conveyed to King County by deed recorded January 18, 1977 as
Recording No. 7701180056;
Together with Lot 22, Vick Addition, according to the plat thereof recorded in volume 45 of plats,
page 27, in King County, Washington;
EXCEPT the Easterly 12 feet of said Lot 22;
Also, together with the East 62.85 feet of Lot 21, Vick Addition, according to the plat thereof recorded in
volume 45 of plats, page 27, in King County, Washington;
Together with a common use easement for ingress and egress over a portion of said Lot 21, described as
follows:
BEGINNING at the Southwest corner of the hereinabove described tract and running thence West in a
projection of the South line of said Lot 21 a distance of 25 feet;
Thence Northeasterly to a point on the West line of said East 62.85 feet of Lot 21 which lies 25 feet
North of the point of beginning;
Thence South along said West line 25 feet to the POINT OF BEGINNING.
(Also known as Parcel A, City of Federal Way Boundary Line Adjustment No. 18-101374-00-SU, in Book
388 of Surveys, Pages 294-296, under recording number 20180731900008, Records of King County,
Washington)
Project: 17764 FW Jacksons
17764L.001.doc
OBH
January 18, 2019
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SCALE: IFor:
HORIZONTAL 1 "=60' VERTICAL N/A
GHA U 18215 72ND AVENUE SOUTH
1p KENT WA 98032
m (425)251-6222
(425)251-8782 FAX
CIVIL ENGINEERING, LAND
°�r a PLANNING, SURVEYING,
ENVIRONMENTAL SERVICES
CITY OF FEDERAL WAY
HIS:
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JOB NUMBER
17764
17764L.001.DOC
SHEET
1 of 1
DATE 1 18 2019
Jacksons 636 Federal Way
Request for Transportation Impact Fee Credit
ATTACHMENT B
Bond Quantities Worksheet/Engineers Cost Estimate
BOND QUANTITIES WORKSHEET
Project Name: Jacksons #636
Project No.: BCE#17764
Site Address: 1520 S 348th Street Federal Way, WA 98003
Fill in those items which pertain to this project and return to the
Public Works Department.
GENERAL CONSTRUCTION
Backfill & Compaction- embankment
8 CY
Backfill & Compaction -trench
11 CY
Clear/Remove Brush, by hand
2363 Acre
Clearing/Grubbing/Tree Removal
13000 Acre
Excavation - bulk
2.5 CY
Excavation -Trench
5 CY
Fencing, chain link, vinyl coated, 6' high
18 LF
Fencing, chain link, gate, vinyl coated, 20'
1563 Each
Fill & compact - common barrow
27 CY
Fill & compact - gravel base
30 CY
Fill & compact - screened topsoil
62 CY
Grading, fine, by hand
2 SY
Grading, fine, with grader
1.25 SY
Monuments with case, 18" long
104 Each
Sensitive Areas Sign
20 Each
Pond Sign
100 Each
Sodding, 1" deep, sloped ground
10 SY
Topsoil Type A (imported)
30 CY
Surveying, line & grade
850 Day
Surveying, lot location/lines
1800 Acre
Traffic control crew ( 2 flaggers)
98 HR
Trail, 4" chipped wood
9 SY
Trail, 4" top course
9.5 SY
Wall, retaining, concrete
66 SF
Wal,,rrockery
13 SF
SUBTOTAL
Public Roadway j Future Right -of -
Improvements J Way Improvemen
$0.00
`
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
450
$1,125.00
$0.00
110
$550.00
$0.00
615
$11,070.00
$0.00
$0.00
$0.00
50
$1,350.00
$0.00
10
$300.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
400
$4,000.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
j
$0.001
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$ 18,395.00 $ -
Item Unit Unit Price Quantity Price Quantity Price
STREET IMPROVEMENT
AC Grinding, 4' wide machine < 1000sy
35 SY
AC Grinding, 4' wide machine 1000-2000sy
8.5 SY
AC Grinding, 4' wide machine > 2000sy
2.5 SY
AC Removal/Disposal
60 SY
Barricade, type III ( Permanent)
55 LF
Curb & Gutter, vertical
15 LF
Curb and Gutter, demolition and disposal
20 LF
Curb, extruded concrete
4.5 LF
Sawcut, asphalt, 3" depth
3.5 LF
Sawcut, concrete, per 1" depth
3 LF
Sealant, asphalt
2 LF
Shoulder, AC, ( see AC road unit price)
0 SY
Shoulder, gravel, 4" thick
11 SY
Sidewalk, 4" thick
40 SY
Sidewalk, 4" thick, demolition and disposal
36 SY
Sidewalk, 6" thick (Round -about, Cul-de-Sac)
45 SY
Sidewalk, 6" thick, demolition and disposal
45 SY
Sign, handicap
100 Each
Sign, roadway
350 Each
Striping, thermoplastic, ( for crosswalk)
3.5 SF
Striping, 4" reflectorized line
0.4 LF
STREET SURFACING
Additional 2.5" Crushed Surfacing
HMA 1/2" Overlay, 1.5" deep
HMA 1/2" Overlay 2" deep
HMA Road, 0.25', 8" rock, First 2500 SY
HMA Road, 0.25', 8" rock, Qty. over 2500 SY
HMA Road, 0.30', 9" Rock, First 2500 SY
HMA Road, 0.3', 9" Rock, Qty Over 2500 SY
HMA Road 0.30', 0.50 ATB, First 2500 SY
HMA Road 0.30', 0.50 ATB, Over 2500 SY
HMA Road, 0.50', 0.50 ATB, First 2500 SY
HMA Road, 0.50', 0.50 ATB, Over 2500 SY
HMA Road, 0.30', 0.85' Class E & 0.50 CSTC
HMA 3/4" or 1", 4" Depth
Gravel Road, 4" rock, First 2500 SY
Gravel Road, 4" rock, Qty. over 2500 SY
Gravel Road, 4" rock, First 2500 SY
Gravel Road, 4" rock, Qty. over 2500 SY
Thickened Edge
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
300
$18,000.00
$0.00
$0.00
$0.00
400
$6,000.00
$0.00
460
$9,200.00
$0.00
$0.00
$0.00
800
$2,800.00
$0.00
$0.00
$0.00
490
$980.00
$0.00
$0.00
$0.00
$0.00
$0.00
360
$14,400.00
$0.00
345
$12,420.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
$0.00
$0.001
$0.00
$0.001
$0.00
$0.00
200
_$80.001
SUBTOTAL $ 63,880.00 $ -
(4" Rock = 2.5 base & 1.5"top course.) 9 1I2" Rock- 6" base & 1.5"1op ourse)
6 SY
14 SY
18 SY
28 SY
21 SY
42 SY
35 SY
33 SY
30 SY
45 SY
42 SY
55 SY
20 SY
15 SY
10 SY
15 SY
10 SY
11 LF
SUBTOTAL
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
470
$19,740.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
470
$9,400.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
$0.00
$0.001
$0.00
$ 29,140.00 $
QuantityItem Unit Unit Price Quantity Price
DRAINAGE (CPP = Corrugated Plastic Pipe, N12 Or Equivalen For Culvert prices, Average of 4' cover was assumes
Access Road, R/D
26 SY
Bollards - fixed
240.74 Each
Bollards - removable
452.34 Each
* (CBs include frame and lid)
Beehive
90 Each
CB Type 1
1650 Each
CB Type IL
1850 Each
CB Type II, 48" diameter
2550 Each
for additional depth over 4'
650 FT
CB Type II, 54" diameter
2700 Each
for additional depth over 4'
600 FT
CB Type 11, 60" diameter
2900 Each
for additional depth over 4'
750 FT
CB Type 11, 72" diameter
4000 Each
for additional depth over 4'
900 FT
Through -curb Inlet Framework (Add)
550 Each
Cleanout, PVC, 6"
250 Each
Cleanout, PVC, 8"
300 Each
Roof Drain, PVC, 6"
17 LF
Storm Main, ADS N-12, 8"
25 LF
Storm Main, ADS N-12, 12"
30 LF
Storm Main, ADS N-12, 15"
35 LF
Storm Main, ADS N-12, 18"
45 LF
Storm Main, ADS N-12, 24"
55 LF
SUBTOTAL
DRAINAGE CONTINUED
Culvert, Concrete, 8"
36 LF
Culvert, Concrete, 12"
43 LF
Culvert, Concrete, 15"
52 LF
Culvert, Concrete, 18"
55 LF
Culvert, Concrete, 24"
85 LF
Ditching
12 CY
Flow Dispersal Trench (1,436 base+)
40 LF
French Drain (3' depth)
39 LF
Geotextile, laid in trench, polypropylene
5 SY
Mid -tank Access Riser, 48" dia, 6' deep
2025 Each
Pond Overflow Spillway
18 SY
Restrictor/Oil Separator, 12"
1500 Each
Restrictor/Oil Separator, 15"
1550 Each
Restrictor/Oil Separator, 18"
1680 Each
Riprap, placed
52 CY
Tank End Reducer (36" diameter)
1280 Each
Trash Rack, 12"
320 Each
Trash Rack, 15"
325 Each
Trash Rack, 18"
350 Each
Trash Rack, 21"
375 Each
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
2
$3,300.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
20
$600.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$ 3,900.00 $ -
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
$0.00
SUBTOTAL $ - $ -
Item Unit Unit Price Quantity Price Quantity Price
UTILITY POLES & STREET LIGHTING Utility pole relocation costs must be accompanied by Franchise Utility's Cost
Utility Pole(s) Relocation
Street Light Poles w/Luminaires
Traffic Signal and Appurtenances
Rectangular Rapid Flashing Beacon (RRFB)
LANDSCAPING & VEGITATION
Street Trees
Median Landscaping
Right -of -Way Landscaping
Wetland Landscaping
WRITE -IN -ITEMS
(Such as detention/water quality vaults.)
Stormwater Quality Vault
Block Wall
Yard Drain
Lump Sum
10000 Each 4 $40,000.00
Bid Price
Bid Price
500 Each
LS
1 LS
1 LS
380000 Each
16 SY
225 CY
LF
FT
SUBTOTAL:
5
$2,500.00
$0.00
$0.00
$0.00
4000
$4,000.00
$0.00
1200
$1,200.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.00
$0.001
$0.00
$0.001
$0.00
(A) $ 47,700.00 (B) $ -
TOTAL: (A) 163015 (B) 0
The following information will be completed by the City of Federal Way Public Works errt: 2�
EXISITNG PUBLIC ROADWAY IMPROVEMENTS (Total A): $ l 77, ; ,'J
FUTURE PUBLIC ROADWAY IMPROVEMENTS (Total B): $
EROSION/SEDIMENT CONTROL (Total C): $
SUBTOTAL (A + B + C): $
30% CONTINGENCY & MOBILIZATION: $
TOTAL BOND AMOUNT: $
EROSION/SEDIMENT CONTROL WORKSHEET
Project Name: Jacksons #636
Project No.: BCE#17764
Site Address: 1520 S 348th Street
Reference #
EROSION/SEDIMENT CONTROL
Backfill & compaction -embankment
Check dams, 4" minus rock
SWDM 5.4.6.3
Crushed surfacing 1 1/4" minus
WSDOT 9-03.9(3
Ditching
Excavation -bulk
Fence, silt
SWDM 5.4.3.1
Fence, Temporary (NGPE)
Hydroseeding
SWDM 5.4.2.4
Jute Mesh
SWDM 5.4.2.2
Mulch, by hand, straw, 3" deep
SWDM 5.4.2.1
Mulch, by machine, straw, 2" deep
SWDM 5.4.2.1
Piping, temporary, CPP, 6"
Piping, temporary, CPP, 8"
Piping, temporary, CPP, 12"
Plastic covering, 6mm thick, sandbagged
SWDM 5.4.2.3
Rip Rap, machine placed; slopes
WSDOT 9-13.1(2
Rock Construction Entrance, 50'x15'x1'
SWDM 5.4.4.1
Rock Construction Entrance, 100'x15'x1'
SWDM 5.4.4.1
Sediment pond riser assembly
SWDM 5.4.5.2
Sediment trap, 5' high berm
SWDM 5.4.5.1
Sed. trap, 5' high, riprapped spillway berm
SWDM 5.4.5.1
Seeding, by hand
SWDM 5.4.2.4
Sodding, 1" deep, level ground
SWDM 5.4.2.5
Sodding, 1" deep, sloped ground
SWDM 5.4.2.5
TESC Supervisor
Water truck, dust control
SWDM 5.4.7
WRITE -IN -ITEMS
Unit
# of
Price Unit
Qty App.
Cost
6.5 CY
0
78 Each
98 CY
50
4900
8 CY
3 CY
600
1800
2 LF
780
1560
2 LF
0
1 SY
50
50
2 SY
0
3 SY
0
1 SY
0
12.5 LF
0
19 LF
0
24 LF
0
3 SY
100
300
50 CY
0
1800 Each
3600 Each
1
3600
3050 Each
21 LF
110
2310
79 LF
0
1 SY
0
8 SY
0
9.5 SY
0
84 HR
0
130 HR
0
Each 0
0
0
ESC SUBTOTAL 14520
30% CONTINGI -- 4356
ESC TOTAL: 18876
Recording Requested By:
When Recorded Mail To:
City Of Federal Way
33325 8th Ave S
Federal Way, WA 98003
Attn: Ann Dower, Public Works
zo, soazz0000as
COVENANT Rec: $102.00
4122/2019 9:36 AM
KING COUNTY, WA
DECLARATION OF COVENANT
Grantor (s): PACWEST ENERGY, LLC, a Delaware limited liability company
Grantee (s): CITY OF FEDERAL WAY, a Washington municipal corporation
Property Legal Description (abbreviated): Lot A, City of Federal Way BLA No. 18-101374-00-
SU, King County Recording #20180731900008, WM, Complete Legal Description indicated
below.
Assessor's Tax Parcel ID#(s): 889700 0115
IN CONSIDERATION OF the approved City of Federal Way ("City") building permit for
application No. 18-102691-00-CO, relating to real property legally described as:
Legal description of property attached hereto as Exhibit "A," and incorporated
herein by reference in King County, Washington, and portions of vacated streets
adjoining ("Property"),
The undersigned as Grantor(s) declares that the above -described Property is hereby subject to a
perpetual easement for a natural or constructed storm water conveyance system ("System") and
hereby dedicates, covenants, and agrees as follows:
1. City shall have the right to ingress and egress over the Property to access such easement
area for inspection of and to reasonably monitor the System for performance,
operational flows or defects in accordance with the City's Surface Water Management
Division procedures.
2. If City determines that maintenance or repair work is required to be done to the System,
the Manager of the Surface Water Management Division of the Department of Public
Works ("Manager") shall give notice of the specific maintenance and/or repair required.
The Manager shall also set a reasonable time in which such work must be completed by
the Grantor, its heirs, successors or assigns. If the above required maintenance and/or
repair is not completed within the time set by the Manager, the City may perform the
required maintenance and/or repair. Written notice will be sent to the Grantor stating the
City's intention to perform such maintenance. Maintenance work will not commence until
at least seven (7) days after such notice is mailed. If, within the sole discretion of the
Manager, there exists an imminent or present danger, said seven (7) day notice period will
be waived and maintenance and/or repair work will begin immediately.
3. If at any time the City reasonably determines that any existing retention/detention system
creates any conditions detrimental to the receiving surface water system, public and/or
private property, the Manager may take any measures pursuant to Federal Way Revised
Code.
4. The Grantor shall assume all responsibility for the cost of any maintenance and for repairs
to the System. Such responsibility shall include reimbursement to the City within thirty
(30) days of the receipt of the invoice for any such work performed. Overdue payments
will require payment of interest at the current legal rate as liquidated damages. If legal
action ensues, the prevailing party is entitled to costs and/or fees.
5. The Grantor is hereby required to obtain written approval from the Manager prior to
filling, piping, cutting, or removing vegetation (except in routine landscape maintenance)
in open vegetated drainage facilities (such as swales, channels, ditches, ponds, etc.), or
performing any alterations or modifications to the drainage facilities contained within
Property as described previously. Any notice or consent required to be given or otherwise
provided for by the provisions of this Declaration of Covenant shall be effective upon
personal delivery, or three (3) days after mailing by Certified Mail, return receipt
requested.
6. Grantor agrees to indemnify, defend, and hold City, its elected officials, officers,
employees, agents, and volunteers harmless from any and all claims, demands, losses,
actions and liabilities (including costs and all attorney fees) to or by any and all persons or
entities, including, without limitation, their respective agents, licensees, or representatives,
arising from, resulting from, or connected with this Declaration of Covenant except to the
extent caused by the sole negligence of the City.
This covenant is intended to protect the value and desirability of the Property, and shall inure
to benefit all of the citizens of the City of Federal Way, and shall run with the land, and shall
touch and concern the land, and shall be binding on all heirs, successors, and assigns.
[signature page to follow]
GRANTOR(S):
PACWEST ENERGY, LLC:
By: Jacksons Food Stores, Inc.
Tfc- lUcknacrar
STATE OF IDAHO )
ss.
COUNTY OF ADA )
On this day personally appeared before me Cory Jackson, to me known to be the Secretary of the
Jacksons Food Stores. Inc. that executed the foregoing instrument, and acknowledged the said
instrument to be the free and voluntary act and deed of said corporation, for the uses and
purposes therein mentioned, and on oath stated that he/she was authorized to execute said
instrument and that the seal affixed, if any, is the corporate seal of said corporation.
GIVEN my hand and official seal this day of rP.b , 20191
(typed/printed name of notary)
Notary Public in and for the tate pf Idaho.
My commission expires
CYNTHIA BURNETr
NOTARY PUBLIC - STATE OF IDAHO
COMMISSION NUMBER 43527
MY COMMISSION EXPIRES 12.18.2022
Rev. 10/17
(EXHIBIT A)
LEGAL DESCRIPTION
A portion of Lots 19, 21 and 22, Vick Addition, according to the plat thereof recorded in Volume 45 of
Plats, page 27, in King County, Washington, lying in the Northeast Quarter of the Southeast Quarter of
Section 20, Township 21 North, Range 4 East, W.M., King County, Washington, more particularly
described as follows:
Lot 19, of Vick Addition, according to the plat thereof recorded in Volume 45 of Plats, page 27, in King
County, Washington;
EXCEPT the East 20 feet thereof conveyed to King County by deed recorded January 18, 1977 as
Recording No. 7701180056;
Together with Lot 22, Vick Addition, according to the plat thereof recorded in volume 45 of plats,
page 27, in King County, Washington;
EXCEPT the Easterly 12 feet of said Lot 22;
Also, together with the East 62.85 feet of Lot 21, Vick Addition, according to the plat thereof recorded in
volume 45 of plats, page 27, in King County, Washington;
Together with a common use easement for ingress and egress over a portion of said Lot 21, described as
follows:
BEGINNING at the Southwest corner of the hereinabove described tract and running thence West in a
projection of the South line of said Lot 21 a distance of 25 feet;
Thence Northeasterly to a point on the West line of said East 62.85 feet of Lot 21 which lies 25 feet
North of the point of beginning;
Thence South along said West line 25 feet to the POINT OF BEGINNING.
(Also known as Parcel A, City of Federal Way Boundary Line Adjustment No. 18-101374-00-SU, in Book
388 of Surveys, Pages 294-296, under recording number 20180731900008, Records of King County,
Washington)
Project: 17764 FW Jacksons
17764L.001.doc
OBH
January 18, 2019
V/1 ✓`%/• A. v/ / rr I*• LJ.I 1/ /■vL.• /V�# rr•f T!"
'.34 COUNTY WASHINGTON
Q ❑ ;' !
❑ ►
Q
r
r
A-8T46'33"
R-25.00'
L=39.17'
EXISTING UTILITY VAULTS
TO BE ADJUSTED TO
FINISHED GRADE WITH
ADA COMPLIANT LID '
276.02
n •
❑ �•
275.93 `•
UPDATE EXISTING LUMINAIRE. SEE 275.9E
TRAFFIC AND ILLUMINATION PLANS. 1�
- A F
.4
275.03± ME
/4'
STA 19+24.54. 9.31'RT
I
F P LAC H N E E T L IN
I '�' RELOCATE TO
LANDSCAPE STRIP
STA 1 1 +74.61, 40.18'RT
I
I
STA 1 1 +84.85, 39.18'RT
i' EXTEND STOP EXISTING
r
i rrnn'
VJ
r
W
Q
r
rA
EXTEND SIDEWALK STRIPING
❑ 76.45± ME TO EXISTING
276.28± ME
7
- {' - -- -- --- --
7 F
4 SLOPE GUTTER PAN TO
7 4 F 7 MATCH ROAD GRADE
(0-3%± CROSS SLOPE)
-11
INTERSECTION EQUATION
1 6TH AVE S STA=12+00.00=
S 348TH ST STA=20+00.00
GRADING NOTES:
ALL SPOT ELEVATIONS SHOWN ARE TO
SURFACE (TOP OF ASPHALT OR TOP C
CONCRETE PAVEMENT, NOT TOP OF
CURB/SIDEWALK) UNLESS OTHERWISE
(TC = TOP OF CONCRETE SIDEWALK/C
ME = MATCH EXISTING ELEVATIONS, TF
OF PAVEMENT AND FL=ELEVATION AT F
LINE)
2. REFER TO SHEET C6.0 FOR FULL GRA
2/11 /2020
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Instrument Number: 20190619000559 Document:COV Rec: $105.00 Page-1 of 7
Record Date:6/19/2019 1:28 PM
King County, WA
Recording Requested By:
When Recorded Mail To:
CITY OF FEDERAL WAY
33325 8th Ave S
FEDERAL WAY, WA 98003
ATTN: JOHN COLE, PW ENGINEERING TECHNICIAN
0
O:rs,*
DECLARATION OF COVENANT FOR iN-IONITORJNG WELLS
.-n
Grantor: PACWEST ENERGY, LLC, a Delaware limited liability company
Grantee: CITY OF FEDERAL WAY, a Washington municipal corporation
Property Legal Description (abbreviated): VICK ADD PCL "A" OF FEDERAL WAY BLA #18-
101374-00-SU REC #20180731900008 SD BLA BEING POR OF LOTS 19 & 21- 22 OF SD
ADD LESS CO RD
Complete Legal Description indicated below.
Assessor's Tax Parcel ID#(s): 889700-0115
IN CONSIDERATION of approval by the City of Federal Way ("City") of an extended right-of-
way use permit No. 19-102003-00-HR ("ROW Permit") for the use of City right-of-way, relating
to real property legally described in Exhibit A ("Property"), the undersigned as Grantor and owner
of the Property covenants and agrees as follows:
1. The Grantor is the owner of the Property.
2. The Grantor has requested issuance of a City of Federal Way ROW Permit pursuant to
FWRC 4.25.100 to place the following right-of-way improvements including, groundwater
monitoring facilities including wells, pipes, and all appurtenances thereto (the
"Improvements"), in the right-of-way located at 1520 S 348TH ST FEDERAL WAY,
WA, which is depicted on Exhibit B-1 (the "ROW"), which is adjacent to the above -
described property.
3. The Grantor acknowledges that the Improvements are located in the ROW. Subject to the
exercise of the City's rights described herein, the City has no responsibility for the
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Instrument Number: 20190619000559 1 ment:COV Rec: $105.00 Page-2 of 7
Record Date:6/19/2019 1:28 PM King County, WA
maintenance of the Improvements in the ROW. Maintenance of the Improvements shall be
the sole responsibility of the Grantor/owner of the Property and its heirs, successor, and/or
assigns. Grantor further acknowledges that and agrees that this Covenant does not create
any rights, titles, or interests in the ROW nor in any way defeats the rights of the City to
such ROW, and further that Grantor agrees that such permission is subject to the terms set
forth in the ROW Permit and Grantor agrees to comply with all ROW Permit requirements
and conditions. Grantor agrees that any use of the ROW is non-exclusive and that the City
retains and reserves the right to use the ROW for any purpose consistent with the terms of
this Covenant.
4. No enlargement or alteration of the Improvements is permitted without prior written -
approval of the City. Routine maintenance is permitted.
5. In the event the City determinestftat the ROW is needed for any public purpose or that the
improvements have become a hazard t4 the safe public use of the ROW, the City may order
the Grantor to remove, repair, or alter the Improvements at the Grantor's sole expense. The
Grantor agrees to immediately comply with any such order.
Upon an order to remove the Improved ents-or termination or revocation of the ROW
Permit, the Grantor shall remove all of the Improvements from the ROW within 90 days of
receiving notice from the Public Works Direct& to do -so. Any costs incurred by the
Grantee in removing any Improvements fron'fhe-ROW shall be a lien on the Property.
Grantor shall remove the Improvements and backfill all wells as prescribed by DOE.
Wells within the roadway prism shall be filled with a minimum of one (1) foot of Control
Density Fill (CDF) and shall be paved with asphalt at. a depth matching existing pavement.
Wells within landscape areas shall be filled with native soil within the top two feet and
shall be landscaped similarly to adjacent area; provided, however, that the City may permit
the Improvements to be abandoned in place in the City's sole discretion and in such a
manner as the City may prescribe. Upon permanent abandonment, the Facilities shall
become the property of the City.
6. City shall have the right to inspect and reasonably monitor the Improvements for
performance or defects. If the City determines that maintenance or repair work is required
to be done to the Improvements, the City Public Works Director ("Director") shall give
notice of the specific maintenance and/or repair required. The Director shall also set a
reasonable time in which such work must be completed by the Grantor. If the above
required maintenance and/or repair is not completed within the time set by the Director, the
City may perform the required maintenance and/or repair. Written notice wi11 be sent to the
Grantor stating,the City's intention to perform such maintenance. Maintenance work will
not commence until at least seven (7) days after such notice is mailed. If, within the sole
discretion of the Director, there exists an imminent or present danger, said seven (7) day
notice period will be waived and maintenance and/or repair work will begin immediately.
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Instrument Number: 20190619000559 Do--)ent:COV Rec: S105.00 Page-3 of 7
Record Date:6/19/2019 1:28 PM King County, WA
f
7. If at any time the City reasvInably determines the Improvements have become a public
health or safety hazard, or if the Grantor fails to comply with any City order issued
pursuant to the terms of this 'Covenant and/or the ROW Permit, the City has the right to
remove, repair, or alter the Improvements, without notice to the Grantor and the Grantor
agrees to compensate the City for all costs of such removal, repair, or alteration.
8. The Grantor's responsibility for the maintenance of the Improvements, shall include
reimbursement to the City within thirty (30) days of the receipt of the invoice for any such
work performed by the City pursuant to the terms of this Covenant. Overdue payments will
require payment of interest at the current legal rate as liquidated damages. If legal action
ensues, the prevailing party is entitled to costs and/or fees.
9. Grantor agrees to indemniidefend, and hold the City, its elected officials, officers,
employees, agents, and volunteers harmless from any and all claims, demands, losses,
actions and liabilities (including costs and all attorney fees) to or by any and all persons or
entities, including, without limitation, their respective agents, licensees, or representatives,
arising from, resulting from, or connected i ith this Covenant except to the extent caused
by the sole negligence of the City.
10. Grantor is prohibited from subdividing the Property without obtaining a plat, short plat, or
binding site plan approval therefore, or if exempt from platting, a right-of-way use permit
for any and all additional lots being created. Ni
y
40,
11. This Covenant is binding upon the heirs, suc:cessofs, and assigns of the Grantor as owner of
the Property and is a covenant running with the land
[Signature Page Follows]
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Instrument Number: 20190619000559 ►ment:COV Rec: $105.00 Page-4 of 7
Record Date:6/19/2019 1:28 PM King County, WA
1. 1XVIN IM C�
PACWEST E GY, LLC:
By:
STATE OF IDAHO )
ss.
COUNTY OF _Ada > `John 4) n
On this day personally appeared before -me to me known .to be the
of PacWest Energy. LLC that executed the foregoing instrument, and
acknowledged the said instrument to be the free and voluntary act and deed of said limited liability
company, for the uses and purposes therein mentioned, and on oath stated that he/she was authorized
to execute said instrument.
GIVEN my hand and official seal this _Bit_day of I N2 , 2011
Notary's signature
AMANDANOYWIRD Notary's printed name p
NOTARY PUBLIC • 5 WTE OF 0110
COMMBMNJMER65M Notary Public in and for the State of Idaho.
L0 WCQW*M E7 PnS 10-7-M My commission expires j 0_ p(7.1
Rev. 10/17
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,Instrument Number: 20190619000559 Document:COV 1$105.00 Page-5 of 7
Record Date:6119120191:28 PM King County, WA
EXHIBITBI
PIPING
II PE.,B�
Idl'��D4 �, ,o• ,s•Q,o
M1K2��h DPo-29 ,
PLANNED I � C
DISPENSERS o
AND CANOPY , I;
EXISTING
DISPENSER I
ISLANDS m�
I DPE B
DPE•TB V'r\ DP5P8
IGW2
I
ASSD •
EXISTING
CANOPY
�
7
uuQ�13A MM
o e+F . 'Pr-ise
,
I
T
�r346TH TREETSOUTH ,i E
� N,4V-17i3
(0eco�raniss.�oredj l
1 �
MW.23 E—�9
�
�
MW-1581ha1
�`
?
will be in new
y
1
sidewalk
r
PLANNED USTs
I
I
1`
1
SEPTIC OR UTILITY
VAULT (UNDERGROUND)
SIDEWALK
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Instrument Number: 20190619000559 Document:Cs cc'. 5105,00 Page-6 of 7
Record Date:6119130191:28 PM King CounO, WA
EXISTING --4
CONVENIENCE
STORE
I
f]f nNG�
PRODUCT
PIPING
PLANNED
DISPENSERS
AND CANOPY I
EXI5T9JG --�
DISPENSER
ISLANDS
i
:XISTING
CANOPY
EXKBITBI
0
r'
/% \
` IRY38 �h1%
i p k�N34 WF17C
)
' 1348THSRREET SOUTH
S
/ i
III EXISTING
IPROPERTY LINE
i�
EXISTING
IFORMER
USTs
Doi
f I I
a
PLANNED LISTS I►
�.
IjII
rW-0
I
1 r
1 4'0or40'
CONCRETE
i VAULTS
Remed'rdan
I
` n
1 '
System Piping
Vault h ROW
0-4-
�
RaAion
System Pipirg
will pass overor
1
underLUDwater
SEPTIC OR
sup lire
VAULT (UNDERGROUND)
SIDEWALK
PARKING
LOT
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Instrument Number: 20190619000559 Document:COV ?$105,00 Page-7 of 7
Record Date:6119120191:28 PM King County, WA
f
i
i5
t
— EXISTING
PROPERTY
i LINE
D
VATER
NEW
PROPERTY
LINE
LEGEND
PROPOSED INTERMEDIATE ZONE DPE WEU.01
pQ PROPOSED DEEP ZONEDPEWELL(41
O PROPOSED DEEP ZONE AIR SPARGEINELL21
Qn PROPOSED SHALLOW MONITORINGWEU.
V PROPOSED INTERMEDIATE MONITORING WELL
?r�EDG�1d0![TO�Y7dl.
s7ii >Nrs,71V7wIKIAW MUL=TMNp35FEETBGS)
MW40 7.-91"91MMILLOCATIOff 0FEE II00
M*1300 c{TE I4nMWELL=TTAWpBDF %$)
PP.0 Pi i C
SL 0 a REET.W1
�.��� �TEnd9ERiY
— — — E.-. l
— .—, —.. P—EXlTiIksGPRaOUCT [BNE
— ——ml—U✓aINEHStfDUTV
— — — w—WATERUNE
— — —''�— SE11'IGLYIOR11RR11M
— —CL—CABLE LINE
— — T — TELEPHONE UNE
— ——aR— OVER HEAD E1.ECfRIGAL
— -- t — UNRNOWNUTILITY LINE
INCITY OF FEDERALWAY PLANNED
ROWTAmNG ,
Wo ANUWX WELL 4KZWAPPROXIMATE LOCATION
AND ANGLESMV1D=
ANGLE BORING DIAECIIONANDAp?W 'EENDPOINT
EXHIBIT B1
GHD
7325mad1rq, 5A 301
Tacoma,Washi*n
T 253 5371218 F2535n16U Wwww.ghdam
https:llrecordsearch.kingcounty.gov)LandmarkWebJsearchlindex?theme=.blue§ion=searchCritedsParcelld&quicksearchSelection=# 7/7
LU
ZW
_ W
J =
2 U)
H to
Z H
00
CM
_
C/
0+00
0+50 _=
93'x35' j , J
Sta. 0+ , -
Sta. 0+1 a
Begin Planing Bituminous
Pavement (Butt Joint) 2+76
1+90, New Casting 14 5'x8'
8 1+10, New Casting i 8J 11' Lt
11- Lt 1+13 21' Lt
21' Lt 4 13'x1' New Casting, 2+71 14
11' Lt 8
1+13 21' Lt
14 12'x8' 2 2+44
--- 12'x8' 14
i 0
54' Rt 2
Sta. 1+15� U)
End Planing Bituminous Pavement (Butt Joint) _
Begin Planing Bituminous Pavement (Edge Grind)
Begin 1" Rut Planing
Begin 1" Prelevel With HMA PG 64-22 CM
U)
i Begin Removal of Type C Traffic Curb
5+76
3 95'x10'x3"
6+38 6+70
3 44'x4'x3" 2 3 108 x4'x3"
16TH AVE S
2+95j7'x8'
3+50 New Casting
20'x8'11 Lt
21' Lt 4+19
7 15' Lt
14 3+67 5+00
7 14' Lt 5'
:ids by ai I'S
2 Gas `i<r4a
Ste �+35, 1f= L
5+23 5+63
6'x4'x3" 3 7 16' Lt
5+01
15' Lt
I
New Casting,3+46 2 ~tom
32' Rt 8 3 38 x4'6" 4+3 3ir4'
i Sta. 2+70 4+83
End 1" Rut Planing 4+20 3 30'x4'x6"
End 1" Prelevel With HMA CI.2" PG 64-22 8138 Rt 5+07
New Casting
70'x10' 30'x4'x63"
Sta. 5+40
End Removal of Type C Traffic Curb
16TH AVE S
12'
2
5+79 3
15'x4'x6" E'
5+94 j�
40'x4'x6" . 3
8+22
7+68 3_j54'x10'x3"
10+34
10, 1 8+53 T
16'x10'x3" 11+28
3 I30'x4'x3" , I8+9F 21 12 20'x8'
31 48'x10'xT. 3 10+76 11 +34
23 x4 x3" 3 91'x4'x3"
-- — - _ -
6+ g NewtCasting 2 New asting
14 6.1'x8' 14 6+77 7+80 r
5'x8' 22'x4'x3"
BUSINESS OPEN [
DURING
I•
75'x14'
sie.a is, 4Fu
CONSTRUCTION sta 7+22, 5TFd
+ Sla 13�00, 30'FU
+� aa�a.•s 1 r ;rs�+
1 3 25'x10'x6" U 3 9+82
I 3 8+78+73 x6" 16'x4'x3"
9+74
8+60 3 6'x4'x6"
—3 :13'x10'x6"
8.1 8+50 New Casting
36' R't
W W
Z W
J =
_ co
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E— U)
PROJECT ENG: VERIFY SCALE UKAVVINU. VtRUJUN 1 REViSION LOG
Ctnr OF rp # DATE DESCRIPTION
BAR IS ONE INCH ON
Jeff Huynh @r� 4��9jy 0,5 3!7/2018 INITIALGESIGN 2018 N H S
Federal Wa PHONE #: ORIGINAL DRAWING.
y -
33325 8TH AVE. SOU253-835-2721 0 � - - 1" SOUTH PHONE: (253) 835-7000 ` PRESERVATION
FEDERAL WAY FAX:(253) 835-2709 EMAIL: IF NOT ONEINCH ON 0NALPROJECT
NCH ADJUST 7a y� WASHINGTON 98003 www.CityOfFederalWay.com THIS
jeff.huynh@cilyoffederalway.wm SCALES ACCORDINGLY.
SITE PREPARATI CONSTRUCTION NOTES.
1 % = BUTT JOINT AT STATION OR LOCATION INDICATED.
FULL DEPTH AT MATCH LINE AND TRANSITION TO 0"
AT DISTANCE DIRECTED BY ENGINEER
2 = PLANE WIDTH AS INDICATED. FULL DEPTH AT
FACE OF GUTTER
3 = DIG OUT AND REPAIR ROAD SECTION PER
SECTIONS & DETAILS SHEET — OF --
4 SOD, INCL. 4" TOPSOIL
5 SAWCUT ASPHALT PAVEMENT OR CONCRETE
6 NOT USED
CONVERT SQUARE LID & FRAME TO ROUND
7 AND ADJUST TO GRADE
8 ADJUST MANHOLE
9 ADJUST CATCH BASIN
10 ADJUST MONUMENT CASE AND COVER
11 A CEMENT CONC. CURB RAMP TYPE 1 PARALLEL
11 B CEMENT CONC. CURB RAMP TYPE 2 PARALLEL
11 C CEMENT CONC. CURB RAMP TYPE SINGLE DIRECTION
11 D CEMENT CONC. CURB RAMP TYPE 1 PERPENDICULAR
12 CEMENT CONC. APPROACH
13 CEMENT CONC. CURB AND GUTTER
14 CEMENT CONC. SIDEWALK
15 DETECTOR LOOP
16 INLET PROTECTION
LEGEND:
C/G = EXISTING CURB & GUTTER
EP = EXISTING EDGE OF PAVEMENT
TE = EXISTING THICKENED EDGE
= MONUMENT CASE
= EXISTING FIRE HYDRANT
L � = EXISTING STORM DRAIN CATCH BASIN
ss = EXISTING MANHOLE
SD = EXISTING STORM DRAIN MANHOLE
"y = EXISTING JUNCTION BOX
= INLET PROTECTION
30 0 30 60
SCALE: 1"=30'
NOTE: SCALEx2 FOR 11x17 SHEET
SCHEDULE A RFS#:
STA 0+78 TO 12+00 1 18-006
SITE PREPARATION & PAVING PLAN A01
16TH AVE S 03 ,,54
p
{mr-10�4co a T. 21/ N.,, R.4E., W.M. �qqff & FED. AID PROJECT N0. M1013(001)
In NE 114 SE //4 SEC. 20 ' _ I
LU o m 4 .o , r CONSTRUCTION NOTES
O WILLIAM M. -Mac PHAIL 11n o` DEPRESS BACK OF SIDEWALK TO MATCH EXISTING GRADE;
IA ! NN - v O k'32 - 7: 2/35-/ 2135- 2 -4 SEE KCRS DWG N0. 13.
ii �g tj }) (� 1\,I - -1---- - - SHARON L MAcPNA1L a
J- {-� •°•••- `•'-`�' 1 / IrJ 13 s i L22 RECONSTRUCT DRIVEWAY; SEE DRi DRIVEWAY PROFILES.
_ 47� m �� r UTIL. EASEME/OT- * N ¢ I 12 ,'I - 1`-1 t' �>=`'C-• T G REMOVE EXISTING SIDEWALK, CURB AND GUTTER.
-- S1; IIt 7 6 Uf' _ C] r B - - - 16 0 REMOVE EXISTING CURB.
I� 44 � N BENJAMIN°ROBERTSOJV &
rI O S N ' :4=7' EXISTING FIRE HYDRANT TO BE RELOCATED BY OTHERS,
_ BENJAMIN H. R BERT O
(� O •. � � � __.� "r-" G EXISTING GUARD POST 10 BE RELOCATED BY OTHERS.
p` I q IS p• 4 IP I 22 = 9 4 O V' REMOVE EXISTING JUNCTION BOX.
AV_ -A swy,xf,Yf 4 ;J Q9 EXISTING VALVE BOX(ES) TO BE ADJUSTED TO GRADE BY OTHERS.
Q ( 9 LSLTFC7 ["1i�D1 I 4�95 (29.?5'+7J ~ EXISTING UTILITY POLE TO BE RELOCATED BY OTHERS.
4' R/W 4+oG(tyl,I'G-) T.E P63.a9 J EXISTING UTILITY VAULT ?0 BE RELOCATED BY OTHERS.
Z O � i7 RELOCATE EXISTING MAILBOX(ES); SEE SCHEDULE ON SHEET 3•
Z ■ cN LE
O 4 /f •' - G) lot
O L.F., 16"0@1-001 r - - ® RELOCATE BOULDER(S) TO BACK OF SIDEWALK.
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— M —MT— w — M —M —M —M —M —M —M —M •-- 401'�
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II 16TH AVE S
as
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U
RELOCATED LUMINAIRE POLE
HEIGHT = 40.0' EX
ARM LENGTH = 14.0' EX
LAMP = 120W LED NEW
LUMENS = 16,000 NEW
INITIAL FIXTURE = GE EVOLVE NEW
TARGET
CALCULATION SUMMARY
ACTUAL
DESIGN CRITERIA
CALCULATION
AVG.
UNIFORMITY
AREA
MAINTAINED
(FC)
,qVG. RATIO
FC
MIN. F
16TH AVE S
1.00
3.00.1
(ARTERIAL STREET)
1.75
2 92:1
S 348TH ST
1.00
3.00:1
(ARTERIAL STREET)
2.72
2.72:1
S 348TH ST & 16TH AVE S
1.50
3.00:1
INTERSECTION
(ARTERIAL STREET)
1.59
2.65:1
�1"MIN®� �
• / '•
HEIGHT = 40.0' EX
ARM LENGTH = 14.0' EX
LAMP = 237W LED NEW
LUMENS = 27,000 NEW
INITIAL FIXTURE = GE EVOLVE NEW
EX SIGNAL POLE
LUMINAIRE HEIGHT = 40.0' EX
LUMINAIRE ARM LENGTH = 14.0' EX
LAMP = 237W LED NEW ,-
LUMENS = 27, 000 NEW
INITIAL FIXTURE = GE EVOLVE NEW W�
RELOCATED LUMINAIRE POLE
HEIGHT = 40.0' EX
ARM LENGTH = 14.0' EX
LAMP = 237W LED NEW
LUMENS = 27,000 NEW
INITIAL FIXTURE = GE EVOLVE NEW
0 30
N HORIZONTAL SCALE
IN FEET
DATE: C QTEN� A J
0610112018 � y Y
Transportation Engineering NorthWest
Transportation Planning I Design I Traffic Impact R Operations
11400 SE 81h Street, Suite 200. Bellevue, WA 98004 1 Office (425) 889-6747
Project Contact: Jaedi Stevens
Phone: 425-250-0868
n
n
3
SITE
DRIVEWA Y
L I
y ♦ �
F
.tl R
JACKSON FUELING FACILITY
FEDERAL WAY, WA
w —
-M,
PHOTOMETRIC CALCULATIONS
HALF STREET PROPOSED CONDITIONS
C
r
0
0
RECEIVED
JUN Aa 2018
CfFY OF FEDERAL WA`!
CLiMMU.N-rN DEVELOPMENT
SHEET
OF
5
1
_IC WORKS
G E 0 TE C H24o1
CONSULTANTS, INC.
ton 98102
Seattle,18FAX
X (42) 7 -8561
(425) 747-5618 FAX (425) 747-8561
June 1, 2017
RECENED
JN 16584
Jacksons aka PacWest Energy, LLC
�&
3450 East Commercial Court
JUN 2 a 2018
CID
Meridian, Idaho 83642
1
CITY OF FEDERAL WAY
Attention: Jack Davis
COMMUNITY DEVELOPME4 NT
..
via email. jack. davisgacksons. com
N
Subject: Geotechnical Engineering Study
W
Proposed Reconstructed Convenience
Store
1520 South 348th Street & 34713 —
16th Avenue South
(Store #636)
Federal Way, Washington
Dear Mr. Davis:
We are pleased to present this geotechnical engineering report for the reconstruction of the
existing Store #636 in Federal Way. The scope of our services consisted of exploring site surface
and subsurface conditions, and then developing this report to provide recommendations for general
earthwork, stormwater infiltration considerations, and design criteria for foundations and retaining
walls. This work was authorized by your acceptance of our proposal, P-9652, dated December 15,
2016.
We were provided with a preliminary site plan developed by Barghausen Consulting Engineers,
Inc., which is dated November 16, 2016. Based on this plan, we understand that the existing
convenience store will be demolished and a new store will be constructed in center of the the
northern lot (#34713). The existing car wash will be demolished to provide new parking spaces.
The relocation of the store will allow additional parking spaces along the southern and eastern side
of the store and along the eastern property line. The existing fuel canopy and pump islands will be
demolished and moved to the north near the southern footprint of the existing convenience store.
The proposed canopy will be larger and contain extra fueling stations. The existing fuel
underground storage tanks (USTs) will remain in their current location on the east side of the south
lot. It is our understanding that the store will be constructed near the existing grade; however deep
excavations on the order of 10 feet or greater may be required for a new stormwater detention vault
on the west side of the new building.
If the scope of the project changes from what we have described above, we should be provided
with revised plans in order to determine if modifications to the recommendations and conclusions of
this report are warranted.
SITE CONDITIONS
SURFACE
The Vicinity Map, Plate 1, illustrates the general location of the subject site consisting of two
adjacent lots in Federal Way. The southern lot (#1520) is rectangular shaped and is located on the
GEOTECH CONSULTANTS, INC.
PacWest Energy JN 16584
June 1, 2017 Page 2
northern side of South 3480 Street with a total of 150 feet of frontage along that street, and 158
feet along W1 Avenue South on the east side. The current one-story convenience store is located
near the center of this parcel, and has a detached drive -through car wash that sits off of the
northeast side of the building. A fueling canopy is located directly south of the building that contains
two pump islands. The fuel USTs are located east of the convenience store. A driving lane wraps
around the north and west sides of the convenience store. The southeast corner of the property is
covered with a grass lawn and several trees line the western property boundary.
The northern lot (#34713) is also rectangular shaped and is located on the western side of 16t'
Avenue South with a total of 79 feet of frontage and a maximum depth of 278 feet. A single story
auto repair shop lies in the north -central portion of the site with parking to the east. The western
portion of this lot contains several storage trailers and heavy equipment lifts. A paved driveway
leads from the eastern parking lot through the western storage area to the northwestern property
boundary. The remainder of the lot is covered with gravel.
The properties in the north and west contain businesses related to automobile repair. The site is
essentially flat. There are no steep slopes on the site or the surrounding commercial properties.
SUBSURFACE
The subsurface conditions were explored by drilling seven test borings at the approximate locations
shown on the Site Exploration Plan, Plate 2. Our exploration program was based on the proposed
construction, anticipated subsurface conditions and those encountered during exploration, and the
scope of work outlined in our proposal.
The test borings were drilled on May 17, 2017 with a large, rubber tracked, hollow -stem auger drill.
Samples were taken at approximate 2.5 and 5-foot intervals with a standard penetration sampler.
This split -spoon sampler, which has a 2-inch outside diameter, is driven into the soil with a 140-
pound hammer falling 30 inches. The number of blows required to advance the sampler a given
distance is an indication of the soil density or consistency. A geotechnical engineer from our staff
observed the drilling process, logged the test borings, and obtained representative samples of the
soil encountered. The Test Boring Logs are attached as Plates 3 through 9.
Soil Conditions
Four test borings were conducted within the northern lot (#34713). Test Borings 1 through
4 encountered 2.5 to 7 feet of loose weathered silty sand that was underlain by dense to
very dense silty sand that is referred to as glacial till. It is possible that the uppermost soil in
Boring 1 is fill. Interbedded at different elevations within the glacial till were layers of sand of
varying thickness. The glacial till sands extended to the maximum explored depths of 16.5
to 21.5 feet.
Three test borings were conducted on the southern property (#1520). Test Borings 5
through 7 encountered 4.5 to 7 feet of fill overlying dense to very dense slightly silty sand
and glacial till. No weathered layer was encountered in our samples, suggesting that the
loose native soils were stripped during the original construction of the gas station. The fill
soils encountered may have been placed during the original construction of the fueling
canopies and LISTS. The dense soils extended to the maximum explored depths of 16.5
feet.
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
JN 16584
Page 3
The buried USTs are likely surrounded by clean gravel, such as pea gravel. The extent of
the backfilled excavation is not known. Considering the impervious nature of the glacial till,
this gravel -filled excavation likely contains some amount of water.
No obstructions were revealed by our explorations. However, debris, buried utilities, and old
foundation and slab elements are commonly encountered on sites that have had previous
development. Although our explorations did not encounter cobbles or boulders, they are
often found in soils that have been deposited by glaciers or fast-moving water.
Groundwater Conditions
Slight perched groundwater seepage was observed at a depth of 16 and 20 feet in Test
Boring 2. It is common to find perched groundwater on top of the glacial till, which is
essentially impervious or trapped in sand seams within the glacial till soils. Groundwater
was also encountered at a depth of 16 feet in Test Boring 7. The test borings were left open
for only a short time period. Therefore, the seepage levels on the logs represent the location
of transient water seepage and may not indicate the static groundwater level. It should be
noted that groundwater levels vary seasonally with rainfall and other factors.
The stratification lines on the logs represent the approximate boundaries between soil types at the
exploration locations. The actual transition between soil types may be gradual, and subsurface
conditions can vary between exploration locations. The logs provide specific subsurface information
only at the locations tested. The relative densities and moisture descriptions indicated on the test
boring logs are interpretive descriptions based on the conditions observed during excavation.
CONCLUSIONS AND RECOMMENDATIONS
GENERAL
THIS SECTION CONTAINS A SUMMARY OF OUR STUDY AND FINDINGS FOR THE PURPOSES OF A
GENERAL OVERVIEW ONLY. MORE SPECIFIC RECOMMENDATIONS AND CONCLUSIONS ARE
CONTAINED IN THE REMAINDER OF THIS REPORT. ANY PARTY RELYING ON THIS REPORT SHOULD
READ THE ENTIRE DOCUMENT.
The test borings conducted for this study encountered dense silty sand and glacial till below 2.5 to
7 feet of fill and loose silty sand. The dense glacial till is very well suited to support the new
building, canopy and stormwater detention vault; conventional shallow foundations bearing directly
on the glacial till or on structural fill placed on top of the glacial till can be used to support the new
structures. Any "thickened slabs" that carry building loads should also be excavated to bearing
soils, just like a footing. We recommend that the final bearing surfaces for foundations be
excavated with a smooth bucket or a "grade" bar to prevent disturbance of the underlying soils that
usually results from the teeth on an excavator's bucket and to maintain the provided high bearing
capacity of the glacial till. Overexcavation through the upper fill soils will likely be necessary to
reach the competent bearing glacial till for the new convenience store and fueling canopy. A typical
detail for overexcavations beneath footings is attached to this report as Plate 11. Due to the
amount of organics in the existing fill soils encountered onsite, they should not be reused as
structural fill under foundations. We recommend structural fill beneath the new footings consist of
2- to 4-inch quarry spalls, 2- to 4-inch concrete spalls, or 2-inch ballast rock that is adequately
compacted by tamping it into place with an excavator bucket.
GEOTECH CONSULTANTS, INC.
PacWest Energy JN 16584
June 1, 2017 Page 4
The eastern columns of the new canopy may extend close to the sidewalls of the old UST
excavation. Any overexcavation necessary below the two eastern canopy columns should be
backfilled with concrete or lean -mix concrete. Compacted structural fill is not appropriate for this
condition.
The native sand soils are silty in nature and thus very moisture sensitive. When wet, these soils
can become softened from equipment and foot traffic. Therefore, we recommend that any bearing
surfaces which are exposed without the need for overexcavation, and thus are not covered with
structural fill, be covered with 4 to 6 inches of quarry spalls, railroad ballast rock, or clean crushed
rock to prevent disturbance of the footing subgrades during the foundation construction. This will
likely be particularly important in the vault excavation.
As discussed above, all seven of the test borings conducted onsite encountered dense glacial till
(hardpan) at depths of 2.5 to 7 feet below the ground surface below a layer of fill or loose
weathered silty sand. The glacial till is essentially impervious, which typically causes any
groundwater that percolates through the upper loose soils to become perched on top of it.
Considering this and the flat topography of subject site and the surrounding area, it is our opinion
that onsite infiltration or dispersion of stormwater is infeasible for this project. In our professional
opinion, the seven test borings conducted onsite are adequate to make a determination of
stormwater infiltration feasibility and no further explorations or testing are necessary.
It is our understanding that a stormwater detention facility is planned for the project. The walls of
storm vaults must be designed as either cantilever or restrained retaining walls, as appropriate.
Wall pressures for the expected soil conditions are presented in the Permanent Foundation and
Retaining Walls section of this report. Permanent retaining walls must be provided with adequate
drainage systems to prevent a build-up of hydrostatic pressure behind the walls. It is also
important that drainage be provided for the backfilled walls above the design dead storage
elevation for the vault. Should drainage not be provided, the walls must be designed for hydrostatic
forces acting on the outside of the structure. The backfill for all underground structures must be
compacted in lifts according to the criteria of this report. Trenches for underground structures and
utilities should not cross a line extending downwards from a new or existing footing at an inclination
of 1:1 (Horizontal:Vertical), or a line extending downwards from a property line at an inclination of
1:1 (H:V). We should be consulted if these excavation zones will be exceeded for installation of
storm facilities or other utilities. The Excavations and Slopes section of this report should be
reviewed for additional recommendations regarding the necessary deep excavations for the
proposed stormwater detention vault.
The erosion control measures needed during the site development will depend heavily on the
weather conditions that are encountered. We anticipate that a silt fence will be needed around the
downslope sides of any cleared areas. Existing pavements, ground cover, and landscaping should
be left in place wherever possible to minimize the amount of exposed soil. Rocked staging areas
and construction access roads should be provided to reduce the amount of soil or mud carried off
the property by trucks and equipment. Wherever possible, the access roads should follow the
alignment of planned pavements. Trucks should not be allowed to drive off of the rock -covered
areas. Cut slopes and soil stockpiles should be covered with plastic during wet weather. Following
clearing or rough grading, it may be necessary to mulch or hydroseed bare areas that will not be
immediately covered with landscaping or an impervious surface. On most construction projects, it
is necessary to periodically maintain or modify temporary erosion control measures to address
specific site and weather conditions.
GEOTECH CONSULTANTS, INC.
PacWest Energy JN 16584
June 1, 2017 Page 5
The drainage and/or waterproofing recommendations presented in this report are intended only to
prevent active seepage from flowing through concrete walls or slabs. Even in the absence of active
seepage into and beneath structures, water vapor can migrate through walls, slabs, and floors from
the surrounding soil, and can even be transmitted from slabs and foundation walls due to the
concrete curing process. Water vapor also results from occupant uses, such as cooking and
bathing. Excessive water vapor trapped within structures can result in a variety of undesirable
conditions, including, but not limited to, moisture problems with flooring systems, excessively moist
air within occupied areas, and the growth of molds, fungi, and other biological organisms that may
be harmful to the health of the occupants. The designer or architect must consider the potential
vapor sources and likely occupant uses, and provide sufficient ventilation, either passive or
mechanical, to prevent a build up of excessive water vapor within the planned structure.
Geotech Consultants, Inc. should be allowed to review the final development plans to verify that the
recommendations presented in this report are adequately addressed in the design. Such a plan
review would be additional work beyond the current scope of work for this study, and it may include
revisions to our recommendations to accommodate site, development, and geotechnical
constraints that become more evident during the review process.
We recommend including this report, in its entirety, in the project contract documents. This report
should also be provided to any future property owners so they will be aware of our findings and
recommendations.
SEISMIC CONSIDERATIONS
In accordance with the International Building Code (IBC), the site soil profile within 100 feet of the
ground surface is best represented by Site Class Type C (Very Dense Soil and Soft Rock). As
noted in the USGS website, the mapped spectral acceleration value for a 0.2 second (Ss) and 1.0
second period (Si) equals 1.28g and 0.49g, respectively.
The site soils are not susceptible to seismic liquefaction because of their dense nature and the
absence of near -surface groundwater. This statement regarding liquefaction includes the
knowledge of the peak ground acceleration that is anticipated under a 1-in-2,500-year seismic
event (Maximum Considered Earthquake).
CONVENTIONAL FOUNDATIONS
The proposed structures can be supported on conventional continuous and spread footings bearing
on undisturbed, dense, glacial till, or on structural fill placed above this competent native soil. See
the section entitled General Earthwork and Structural Fill for recommendations regarding the
placement and compaction of structural fill beneath structures. Adequate compaction of structural
fill should be verified with frequent density testing during fill placement. Prior to placing structural fill
beneath foundations, the excavation should be observed by the geotechnical engineer to document
that adequate bearing soils have been exposed.
We recommend that continuous and individual spread footings have minimum widths of 12 and 16
inches, respectively. Exterior footings should also be bottomed at least 18 inches below the lowest
adjacent finish ground surface for protection against frost and erosion. The local building codes
should be reviewed to determine if different footing widths or embedment depths are required.
GEOTECH CONSULTANTS, INC.
PacWest Energy JN 16584
June 1, 2017 Page 6
Footing subgrades must be cleaned of loose or disturbed soil prior to pouring concrete. Depending
upon site and equipment constraints, this may require removing the disturbed soil by hand.
Depending on the final site grades, overexcavation may be required below the footings to expose
competent native soil. Unless lean concrete is used to fill an overexcavated hole, the
overexcavation must be at least as wide at the bottom as the sum of the depth of the
overexcavation and the footing width. For example, an overexcavation extending 2 feet below the
bottom of a 2-foot-wide footing must be at least 4 feet wide at the base of the excavation. If lean
concrete is used, the overexcavation need only extend 6 inches beyond the edges of the footing. A
typical detail for overexcavation beneath footings is attached as Plate 11.
The following allowable bearing pressures appropriate for footings constructed according to the
above recommendations:
Detention vault footings placed directly on I
4,000 psf
com etent, native soil
Building foundations supported on 2,500 psf
competent native soils or on structural fill
placed above competent native soil
Where: (i) psf is pounds per square foot.
A one-third increase in these design bearing pressures may be used when considering short-term
wind or seismic loads. For the above design criteria, it is anticipated that the total post -construction
settlement of footings founded on competent native soil, or on structural fill up to 5 feet in
thickness, will be less than one inch.
Lateral loads due to wind or seismic forces may be resisted by friction between the foundation and
the bearing soil, or by passive earth pressure acting on the vertical, embedded portions of the
foundation. For the latter condition, the foundation must be either poured directly against relatively
level, undisturbed soil or be surrounded by level, well -compacted fill. We recommend using the
following ultimate values for the foundation's resistance to lateral loading:
ULTIMATE
P.,UZANIETER VALUE
Coefficient of Friction 0.50
Passive Earth Pressure 300 pcf
Where: pcf is Pounds per Cubic Foot, and Passive Earth
Pressure is computed using the Equivalent Fluid Density.
If the ground in front of a foundation is loose or sloping, the passive earth pressure given above will
not be appropriate. We recommend maintaining a safety factor of at least 1.5 for the foundation's
resistance to lateral loading, when using the above ultimate values.
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
FOUNDATION AND RETAINING WALLS
JN 16584
Page 7
Retaining walls backfilled on only one side should be designed to resist the lateral earth pressures
imposed by the soil they retain. The following recommended parameters are for walls that restrain
level backfill:
Where: pcf is Pounds per Cubic Foot, and Active and Passive Earth Pressures
are computed using the Equivalent Fluid Pressures.
" For a restrained detention vault wall that cannot deflect at least 0.002 times
its height, a uniform lateral pressure equal to 22H psf should be used for the
active design earth pressure. H is the effective design height of the vault wall.
H would be measured from the final ground surface to the base of the vault wall, where it connects
to the foundation. The design values given above do not include the effects of any hydrostatic
pressures behind the walls and assume that no surcharges, such as those caused by slopes,
vehicles, or adjacent foundations will be exerted on the walls. If these conditions exist, those
pressures should be added to the above lateral soil pressures. Where sloping backfill is desired
behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order
to provide the appropriate design earth pressures. The surcharge due to heavy truck loads behind
the vault walls can be accounted for by adding a uniform pressure equal to 3 feet multiplied by the
above active fluid density. Heavy construction equipment should not be operated behind retaining
and foundation walls within a distance equal to the height of a wall, unless the walls are designed
for the additional lateral pressures resulting from the equipment.
The values given above are to be used to design only permanent foundation and retaining walls
that are to be backfilled, such as conventional walls constructed of reinforced concrete or masonry.
It is not appropriate to use the above earth pressures and soil unit weight to back -calculate soil
strength parameters for design of other types of retaining walls, such as soldier pile, reinforced
earth, modular or soil nail walls. We can assist with design of these types of walls, if desired. The
passive pressure given is appropriate only for a shear key poured directly against undisturbed
native soil, or for the depth of level, well -compacted fill placed in front of a retaining or foundation
wall. The values for friction and passive resistance are ultimate values and do not include a safety
factor. Restrained wall soil parameters should be utilized for a distance of 1.5 times the wall height
from corners or bends in the walls. This is intended to reduce the amount of cracking that can
occur where a wall is restrained by a corner.
Wall Pressures Due to Seismic Forces
The surcharge wall loads that could be imposed by the design earthquake can be modeled
by adding a uniform lateral pressure to the above -recommended active pressure. The
recommended surcharge pressure is 7H pounds, per square foot (psf), where H is the
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
JN 16584
Page 8
design retention height of the wall. Using this increased pressure, the safety factor against
sliding and overturning can be reduced to 1.2 for the seismic analysis.
Retaining Wall Backfill and Waterproofing
Backfill placed behind retaining or foundation walls should be coarse, free -draining
structural fill containing no organics. This backfill should contain no more than 5 percent silt
or clay particles and have no gravel greater than 4 inches in diameter. The percentage of
particles passing the No. 4 sieve should be between 25 and 70 percent. If retaining or vault
walls are backfilled with on -site soils, a minimum 12-inch width of free -draining gravel
should be placed against the walls to allow rapid drainage down to the footing drain. For
the detention vault, a drainage composite similar to Miradrain 6000 could be used instead of
the 12-inch width of gravel. The drainage composites should be hydraulically connected to
the foundation drain system. Free -draining backfill or gravel should be used for the entire
width of the backfill where seepage is encountered. For increased protection, drainage
composites should be placed along cut slope faces, and the walls should be backfilled
entirely with free -draining soil. The later section entitled Drainage Considerations should
also be reviewed for recommendations related to subsurface drainage behind foundation
and retaining walls.
The purpose of these backfill requirements is to ensure that the design criteria for a
retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the
wall. Also, subsurface drainage systems are not intended to handle large volumes of water
from surface runoff. The top 12 to 18 inches of the backfill should consist of a compacted,
relatively impermeable soil or topsoil, or the surface should be paved. The ground surface
must also slope away from backfilled walls to reduce the potential for surface water to
percolate into the backfill. Water percolating through pervious surfaces (pavers, gravel,
permeable pavement, etc.) must also be prevented from flowing toward walls or into the
backfill zone. The compacted subgrade below pervious surfaces and any associated
drainage layer should therefore be sloped away. Alternatively, a membrane and subsurface
collection system could be provided below a pervious surface.
It is critical that the wall backfill be placed in lifts and be properly compacted, in order for the
above -recommended design earth pressures to be appropriate. The wall design criteria
assume that the backfill will be well -compacted in lifts no thicker than 12 inches. The
compaction of backfill near the walls should be accomplished with hand -operated
equipment to prevent the walls from being overloaded by the higher soil forces that occur
during compaction. The section entitled General Earthwork and Structural Fill contains
additional recommendations regarding the placement and compaction of structural fill
behind retaining and foundation walls.
The above recommendations are not intended to waterproof below -grade walls, or to
prevent the formation of mold, mildew or fungi in interior spaces. Over time, the
performance of subsurface drainage systems can degrade, subsurface groundwater flow
patterns can change, and utilities can break or develop leaks. Therefore, waterproofing
should be provided where future seepage through the walls is not acceptable. This typically
includes limiting cold -joints and wall penetrations, and using bentonite panels or
membranes on the outside of the walls. There are a variety of different waterproofing
materials and systems, which should be installed by an experienced contractor familiar with
the anticipated construction and subsurface conditions. Applying a thin coat of asphalt
emulsion to the outside face of a wall is not considered waterproofing, and will only help to
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
JN 16584
Page 9
reduce moisture generated from water vapor or capillary action from seeping through the
concrete. As with any project, adequate ventilation of basement and crawl space areas is
important to prevent a build up of water vapor that is commonly transmitted through
concrete walls from the surrounding soil, even when seepage is not present. This is
appropriate even when waterproofing is applied to the outside of foundation and retaining
walls. We recommend that you contact an experienced envelope consultant if detailed
recommendations or specifications related to waterproofing design, or minimizing the
potential for infestations of mold and mildew are desired.
The General, Slabs -On -Grade, and Drainage Considerations sections should be
reviewed for additional recommendations related to the control of groundwater and excess
water vapor for the anticipated construction.
SLABS -ON -GRADE
The building floors can be constructed as slabs -on -grade atop non -organic native soil, or on
structural fill. The subgrade soil must be in a firm, non -yielding condition at the time of slab
construction or underslab fill placement. Any soft areas encountered should be excavated and
replaced with select, imported structural fill. If the existing fill is left in place under a slab, it may
undergo noticeable settlement relative to the foundations.
Even where the exposed soils appear dry, water vapor will tend to naturally migrate upward through
the soil to the new constructed space above it. This can affect moisture -sensitive flooring, cause
imperfections or damage to the slab, or simply allow excessive water vapor into the space above
the slab. All interior slabs -on -grade should be underlain by a capillary break drainage layer
consisting of a minimum 4-inch thickness of clean gravel or crushed rock that has a fines content
(percent passing the No. 200 sieve) of less than 3 percent and a sand content (percent passing the
No. 4 sieve) of no more than 10 percent. Pea gravel or crushed rock are typically used for this
layer.
As noted by the American Concrete Institute (ACI) in the Guides for Concrete Floor and Slab
Structures, proper moisture protection is desirable immediately below any on -grade slab that will be
covered by tile, wood, carpet, impermeable floor coverings, or any moisture -sensitive equipment or
products. ACI also notes that vapor retarders such as 6-mil plastic sheeting have been used in the
past, but are now recommending a minimum 10-mil thickness for better durability and long term
performance. A vapor retarder is defined as a material with a permeance of less than 0.3 perms,
as determined by ASTM E 96. It is possible that concrete admixtures may meet this specification,
although the manufacturers of the admixtures should be consulted. Where vapor retarders are
used under slabs, their edges should overlap by at least 6 inches and be sealed with adhesive
tape. The sheeting should extend to the foundation walls for maximum vapor protection. If no
potential for vapor passage through the slab is desired, a vapor barrier should be used. A vapor
barrier, as defined by ACI, is a product with a water transmission rate of 0.01 perms when tested in
accordance with ASTM E 96. Reinforced membranes having sealed overlaps can meet this
requirement.
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
EXCAVATIONS AND SLOPES
A 16584
Page 10
Excavation slopes should not exceed the limits specified in local, state, and national government
safety regulations. Temporary cuts to a depth of about 4 feet may be attempted vertically in
unsaturated soil, if there are no indications of slope instability. However, vertical cuts should not be
made near property boundaries, or existing utilities and structures. Based upon Washington
Administrative Code (WAC) 296, Part N, the underlying dense glacial till at the subject site would
generally be classified as Type A. Therefore, temporary cut slopes greater than 4 feet in height
should not be excavated at an inclination steeper than 0.75:1 (Horizontal:Vertical), extending
continuously between the top and the bottom of a cut. The loose upper native and fill soils would
be classified as Type B soils and should not be excavated at an inclination steeper than 1:1 (H:V).
It should be noted that our explorations onsite were only moderately deep, extending only to a
maximum depth of 21.5 feet below the existing site grade. Excavations for the proposed
stormwater detention vault probably will not extend deeper than this. If they do, and differing soil
conditions are encountered below the maximum explored depth of our explorations, the above -
stated allowable temporary cut slope inclinations may need to be modified. This is particularly true
if heavy groundwater seepage and/or caving conditions are encountered in the cuts. In these
instances, measures such as placing ballast rock against the cut slopes to buttress the cut face
can be necessary. It would be prudent to excavate a test pit in the area of the proposed vault to the
design bottom -of -excavation early in the construction of the project determine if any unexpected
soil and/or groundwater conditions need to be addressed.
The above -recommended temporary slope inclinations are based on the conditions exposed in our
explorations, and on what has been successful at other sites with similar soil conditions. It is
possible that variations in soil and groundwater conditions will require modifications to the
inclination at which temporary slopes can stand. Temporary cuts are those that will remain
unsupported for a relatively short duration to allow for the construction of foundations, retaining
walls, or utilities. Temporary cut slopes should be protected with plastic sheeting during wet
weather. It is also important that surface runoff be directed away from the top of temporary slope
cuts. Cut slopes should also be backfilled or retained as soon as possible to reduce the potential
for instability. Please note that sand and/or loose soil can cave suddenly and without warning.
Excavation, foundation, and utility contractors should be made especially aware of this potential
danger. These recommendations may need to be modified if the area near the potential cuts has
been disturbed in the past by utility installation, or if settlement -sensitive utilities are located nearby.
All permanent cuts into native soil should be inclined no steeper than 2:1 (H:V). Fill slopes should
not be constructed with an inclination greater than 2.5:1 (H:V). To reduce the potential for shallow
sloughing, fill must be compacted to the face of these slopes. This can be accomplished by
overbuilding the compacted fill and then trimming it back to its final inclination. Adequate
compaction of the slope face is important for long-term stability and is necessary to prevent
excessive settlement of patios, slabs, foundations, or other improvements that may be placed near
the edge of the slope.
Water should not be allowed to flow uncontrolled over the top of any temporary or permanent
slope. All permanently exposed slopes should be seeded with an appropriate species of vegetation
to reduce erosion and improve the stability of the surficial layer of soil.
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
DRAINAGE CONSIDERATIONS
JN 16584
Page 11
Footing drains should be used where: (1) Crawl spaces or basements will be below a structure; (2)
A slab is below the outside grade; or, (3) The outside grade does not slope downward from a
building. Drains should also be placed at the base of all earth -retaining walls. These drains should
be surrounded by at least 6 inches of 1-inch-minus, washed rock that is encircled with non -woven,
geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar material). At its highest point, a
perforated pipe invert should be at least 6 inches below the bottom of a slab floor or the level of a
crawl space. As mentioned in the General section, footing drains placed on the outside of
detention vaults should be set close to the design dead storage elevation The discharge pipe for
subsurface drains should be sloped for flow to the outlet point. Roof and surface water drains must
not discharge into the foundation drain system. A typical drain detail is attached to this report as
Plate 10. For the best long-term performance, perforated PVC pipe is recommended for all
subsurface drains.
As a minimum, a vapor retarder, as defined in the Slabs -On -Grade section, should be provided in
any crawl space area to limit the transmission of water vapor from the underlying soils. Crawl space
grades are sometimes left near the elevation of the bottom of the footings. As a result, an outlet
drain is recommended for all crawl spaces to prevent an accumulation of any water that may
bypass the footing drains. Providing even a few inches of free draining gravel underneath the vapor
retarder limits the potential for seepage to build up on top of the vapor retarder.
Slight perched groundwater was observed during our field work. If seepage is encountered in an
excavation, it should be drained from the site by directing it through drainage ditches, perforated
pipe, or French drains, or by pumping it from sumps interconnected by shallow connector trenches
at the bottom of the excavation.
The excavation and site should be graded so that surface water is directed off the site and away
from the tops of slopes. Water should not be allowed to stand in any area where foundations,
slabs, or pavements are to be constructed. Final site grading in areas adjacent to a building should
slope away at least 2 percent, except where the area is paved. Surface drains should be provided
where necessary to prevent ponding of water behind foundation or retaining walls. A discussion of
grading and drainage related to pervious surfaces near walls and structures is contained in the
Foundation and Retaining Walls section.
PAVEMENT AREAS
The pavement section may be supported on competent, native soil or on structural fill compacted to
a 95 percent density. The pavement subgrade must be in a stable, non -yielding condition at the
time of paving. Granular structural fill or geotextile fabric may be needed to stabilize soft, wet, or
unstable areas. In most instances where unstable subgrade conditions are encountered, an
additional 12 inches of granular structural fill will stabilize the subgrade, except for very soft areas
where additional fill could be required. The subgrade should be evaluated by Geotech Consultants,
Inc., after the site is stripped and cut to grade. Recommendations for the compaction of structural
fill beneath pavements are given in the section entitled General Earthwork and Structural Fill.
The performance of site pavements is directly related to the strength and stability of the underlying
subgrade.
The pavement for lightly loaded traffic and parking areas should consist of 2 inches of asphalt
concrete (AC) over 4 inches of crushed rock base (CRB) or 3 inches of asphalt -treated base (ATB).
GEOTECH CONSULTANTS, INC.
PacWest Energy JN 16584
June 1, 2017 Page 12
We recommend providing heavily loaded areas with 3 inches of AC over 6 inches of CRB or 4
inches of ATB. Heavily loaded areas are typically main driveways, dumpster sites, or areas with
truck traffic. Increased maintenance and more frequent repairs should be expected if thinner
pavement sections are used.
Where concrete pavements are used, they should have a minimum thickness of 7 inches and be
reinforced with rebar. Typically, #4 rebar spaced 18-inches on center in both directions is
appropriate. This concrete pavement section should be sufficient to handle heavy trucks.
The pavement section recommendations and guidelines presented in this report are based on our
experience in the area and on what has been successful in similar situations. As with any
pavements, some maintenance and repair of limited areas can be expected as the pavement ages.
Cracks in the pavement should be sealed as soon as possible after they become evident, in order
to reduce the potential for degradation of the subgrade from infiltration of surface water. For the
same reason, it is also prudent to seal the surface of the pavement after it has been in use for
several years. To provide for a design without the need for any maintenance or repair would be
uneconomical.
GENERAL EARTHWORK AND STRUCTURAL FILL
All building and pavement areas should be stripped of surface vegetation, topsoil, organic soil, and
other deleterious material. It is important that existing foundations be removed before site
development. The stripped or removed materials should not be mixed with any materials to be used
as structural fill, but they could be used in non-structural areas, such as landscape beds.
Structural fill is defined as any fill, including utility backfill, placed under, or close to, a building,
behind permanent retaining or foundation walls, or in other areas where the underlying soil needs
to support loads. All structural fill should be placed in horizontal lifts with a moisture content at, or
near, the optimum moisture content. The optimum moisture content is that moisture content that
results in the greatest compacted dry density. The moisture content of fill is very important and
must be closely controlled during the filling and compaction process.
The allowable thickness of the fill lift will depend on the material type selected, the compaction
equipment used, and the number of passes made to compact the lift. The loose lift thickness
should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not
sufficiently compacted, it can be recompacted before another lift is placed. This eliminates the need
to remove the fill to achieve the required compaction.
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
J N 16584
Page 13
The following table presents recommended relative compactions for structural fill:
Where: Minimum Relative compaction is the ratio, expressed in
percentages, of the compacted dry density to the maximum dry
density, as determined in accordance with ASTM Test
Designation D 1557-91 (Modified Proctor).
The General section should be reviewed for considerations related to the reuse of on -site soils.
Structural fill that will be placed in wet weather should consist of a coarse, granular soil with a silt or
clay content of no more than 5 percent. The percentage of particles passing the No. 200 sieve
should be measured from that portion of soil passing the three -quarter -inch sieve.
LIMITATIONS
The conclusions and recommendations contained in this report are based on site conditions as
they existed at the time of our exploration and assume that the soil and groundwater conditions
encountered in the test pits are representative of subsurface conditions on the site. If the
subsurface conditions encountered during construction are significantly different from those
observed in our explorations, we should be advised at once so that we can review these conditions
and reconsider our recommendations where necessary. Unanticipated conditions are commonly
encountered on construction sites and cannot be fully anticipated by merely taking samples in test
pits. Subsurface conditions can also vary between exploration locations. Such unexpected
conditions frequently require making additional expenditures to attain a properly constructed
project. It is recommended that the owner consider providing a contingency fund to accommodate
such potential extra costs and risks. This is a standard recommendation for all projects.
This report has been prepared for the exclusive use of PacWest Energy, LLC and its
representatives, for specific application to this project and site. Our conclusions and
recommendations are professional opinions derived in accordance with our understanding of
current local standards of practice, and within the scope of our services. No warranty is expressed
or implied. The scope of our services does not include services related to construction safety
precautions, and our recommendations are not intended to direct the contractor's methods,
techniques, sequences, or procedures, except as specifically described in our report for
consideration in design. Our services also do not include assessing or minimizing the potential for
biological hazards, such as mold, bacteria, mildew and fungi in either the existing or proposed site
development.
GEOTECH CONSULTANTS, INC.
PacWest Energy
June 1, 2017
ADDITIONAL SERVICES
JN 16584
Page 14
Geotech Consultants, Inc. should be retained to provide geotechnical consultation, testing, and
observation services during construction. This is to confirm that subsurface conditions are
consistent with those indicated by our exploration, to evaluate whether earthwork and foundation
construction activities comply with the general intent of the recommendations presented in this
report, and to provide suggestions for design changes in the event subsurface conditions differ
from those anticipated prior to the start of construction. However, our work would not include the
supervision or direction of the actual work of the contractor and its employees or agents. Also, job
and site safety, and dimensional measurements, will be the responsibility of the contractor.
During the construction phase, we will provide geotechnical observation and testing services when
requested by you or your representatives. Please be aware that we can only document site work
we actually observe. It is still the responsibility of your contractor or on -site construction team to
verify that our recommendations are being followed, whether we are present at the site or not.
The scope of our work did not include an environmental assessment, but we can provide this
service, if requested.
The following plates are attached to complete this report:
Plate 1
Vicinity Map
Plate 2
Site Exploration Plan
Plates 3 - 9
Test Boring Logs
Plate 10
Typical Footing Drain Detail
Plate 11
Typical Footing Overexcavation Detail
We appreciate the opportunity to be of service on this project. Please contact us if you have any
questions, or if we can be of further assistance.
/& //§Z)- - : '-
Matt McGinnis
Geotechnical Engineer
MKM/MRM:mw
Respectfully submitted,
GEOTECH CONSULTANTS, INC.
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Marc R. McGinnis, P.E.
Principal
CC: Barghausen Consulting Engineers — Caryl Pinner
via email. cpinner@barghausen.com
GEOTECH CONSULTANTS, INC.
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SITE EXPLORATION PLAN
1520 S 348th St. & 34713 - 16th Ave. S
Federal Way, Washington
Job No: Date: Plate:
16584 1 June 2017 No Scale 1 2
BORING 1
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Description
2-inches of asphalt over;
Brown slightly silty SAND with gravel, fine to medium -grained, moist, loose
-becomes gray -brown with organics
-becomes gray, fine to coarse -grained, dense
-becomes gray, increased gravel content
-becomes gray with trace rust, very dense
* Test boring was terminated on May 17, 2017 at 16.5 feet.
* No groundwater was encountered during drilling.
GEOTECH
CONSULTANT'S, INC.
TEST BORING LOG
1520 S 348th St. and 34713 - 16th Ave. S
Federal Way, Washington
Job Date: Logged by: I plate:
16584 June 2017 MKM 3
`) ge .t 4` 11 BORING 2
/ �e� C-1-b", JAGS
2-inches of asphalt over;
Description
Brown slightly silty SAND with gravel, fine to coarse -grained, moist,
12 1 1 U419 medium -dense
5€r;
-becomes gray, fine to medium -grained, very dense (GLACIAL TILL)
72 1 2
50 3
2"
10 50 4
5.5'SM
15
2
-with occasional clean sand seams
-with a thin wet zone
Z l I "3
-becomes very moist to wet
76 6
77 * Test boring was terminated at 21.5 feet on May 17, 2017.
* Slight perched groundwater was encountered at 16 and 20 feet
during drilling.
GEOTE CH
CONSULTANTS, INC.
TEST BORING LOG
1520 S 348th St. and 34713 - 16th Ave. S
Federal Way, Washington
Job
Date:
Logged by:
Plate:
16584
June 2017
1 MKM
4
5
10
15
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BORING 3
oo t 5�� JAG5 Description
Gravel over;
Brown silty SAND with gravel, fine to coarse -grained, very moist, loose
18 1
-becomes gray, dense
43 2
67 3 -becomes very dense
40 4 SM -becomes moist to very moist, dense
50 -becomes fine to coarse -grained, very moist, very dense
i
311 5 i s
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SM 69 6 i c Gray very gravelly, slightly silty SAND, fien to coarse -grained, moist, very dense
Sao o,
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* Test boring was terminated at 21.5 feet on May 17, 2017.
* No groundwater was encountered during drilling.
GEOTECH
CONSULTANTS, INC.
TEST BORING LOG
1520 S 348th St. and 34713 - 16th Ave. S
Federal Way, Washington
Job Date: Logged by: Plate:
16584 1 June 2017 1 MKM 1 5
L�
10
15
43 1 1 1
4�311111119
6160 MCM11
Description
2-inches of asphalt over;
Brown silty SAND with organics, fine to medium -grained, wet, loose
-becomes gray, moist, dense (GLACIAL TILL)
-becomes fine to coarse -grained, very dense
M -increased gravel content with trace rust, becomes dense
41 3
32 4
-with thin fine to medium -grained sand seams
31 5 F:
* Test boring was terminated at 16.5 feet on May 17, 2017,
* No groundwater was encountered during drilling.
GEOTECH
CONSULTANT'S, INC.
TEST BORING LOG
1520 S 348th St. and 34713 - 16th Ave. S
Federal Way, Washington
Job Date: Logged by: Plate:
16584 June 2017 MKM 6
5
10
15
�'P �8
BORING 5
Description
2-inches of asphalt over;
FILL grown silty SAND with gravel, fine to coarse -grained, moist, medium -dense (FILL)
12 1
Gray -brown gravelly, silty SAND, fine to medium -grained, moist, very dense
62 2
-becomes fine to coarse -grained
73 3
sM
64 4 -increased silt content
50
5
5.511
* Test boring was terminated at 16 feet on May 17, 2017.
* No groundwater was encountered during drilling.
GEOTECH
CONSULTANT'S, INC.
TEST BORING LOG
1520 S 348th St. and 34713 -16th Ave. S
Federal Way, Washington
Job Date: Logged by: Plate:
16584 June 2017 MKM I 7
61
10
15
K+1
12
65
46
BORING 6
J5� Description
2-inches of asphalt over;
Gray -brown SAND, fine to medium -grained, moist, loose (FILL)
1 FILL -becomes gray, increased silt content, fine to coarse -grained, medium -dense
3 11 SP Brown with rust, slightly silty SAND, fine to medium -grained, very moist to wet,
SM medium -dense
-becomes gray, increased silt content, fine to coarse -grained, moist
Gray gravelly, silty SAND, fine to medium -grained, very moist, dense
4 (GLACIAL TILL)
-becomes moist
!SM
-becomes fine to coarse -grained, very moist, very dense
5 --
* Test boring was terminated at 16.5 feet on May 17, 2017.
* No groundwater was encountered during drilling.
GEOTECH
CONSULTANTS, INC.
TEST BORING LOG
1520 S 348th St. and 34713 - 16th Ave. S
Federal Way, Washington
Job Date: Logged by: Plate:
16584 June 2017 MKM 1 8
5
10
15
14'1001eplwlol_��P'
[pt gBORING 7
"SCj
11
1 14
1 11
1 37
39
2-inches of asphalt over;
Description
Gray SAND, fine to medium -grained, moist, medium -dense (FILL)
1 , FILL
2 -becomes gray -brown
3 Gray to gray -brown gravelly, silty SAND, fine to coarse -grained, moist, dense
i
-becomes very moist to wet, very dense
4 t:
sM
-becomes dense 5
-becomes blue -gray, fine-grained, wet
* Test boring was terminated at 16.5 feet on May 17, 2017.
* Groundwater was encountered at 16 feet during drilling.
GEOTECH
CONSULTANT'S, INC.
TEST BORING LOG
1520 S 348th St. and 34713 - 16th Ave. S
Federal Way, Washington
Job Date: Logged by: I plate: 9
16584 June 2017 MKM
Slope backfill away from
foundation. Provide surface
drains where necessary.
Backfill
(See text for
requirements)
Nonwoven Geotextile
Washed Rock Filter Fabric
(7/8" min. size)
c� °J vL aC7 v�
a � a
Cn
4" min.
M
C
"L7
s
0
Tightline Roof Drain
(Do not connect to footing drain)
Possible Slab
YJO. •v•vD v.y'0 P�°•°•°•aP°a•0'a�°•p•@
� °0 �p� °a�a.vp� p••e.ip� �•a.op� ° ^a.o�
4" Perforated Hard PVC Pipe
(Invert at least 6 inches below
slab or crawl space. Slope to
drain to appropriate outfall.
Place holes downward.)
Vapor Retarder/Barrier and
Capillary Break/Drainage Layer
(Refer to Report text)
NOTES:
(1) In crawl spaces, provide an outlet drain to prevent buildup of water that
bypasses the perimeter footing drains.
(2) Refer to report text for additional drainage, waterproofing, and slab considerations.
GEOTECH
CONSULTANTS, INC.
FOOTING DRAIN DETAIL
1520 S 348th St. & 34713 - 16th Ave. S
Federal Way, Washington
Job No: Date: Plate:
16584 1 June 2017 10
Unsurtable
,::,i011S
o.Pp°'PP°.a ',�7°•.].qp'p°�-c� 0*.p�-pDC.a�•P°�'
e.ap� a' •�.ap� .° •d.op`� ° G ] n �'•d.9p : c.ao� '':c.v
�..�.4 w X c:.0:,�`.a;. ,.- .p;•Q,.o°.�
•�•° p0°•G O vGO.;'p° Q1D°•�.a op°•P
pP�c° QOd:^ o p0�a, i-T�.°0�1aa ;�1°0�°°�°:
ma
•70p°�` Po °,Q,°�'�q• °Width of Overexcavation ° °•cpp° °
Structural Fill (refer to report for
gradation and compaction requirements).
See Note 2 for condition where lean
concrete is used to backfill the
overexcavation.
Suitable Bearing Soil (Refer to report for description)
verify by Geotechnical Engineer prior to placing Structural
Fill.
Width of Overexcavation = Footing Width (FW) + Depth of Overexcavation
NOTES:
1. Refer to report text for additional overexcavation, foundation, and structural fill considerations.
2. Where lean concrete (minimum 1-1/2 sacks of cement per cubic yard) is used to backfill the
overexcavation, the overexcavation must extend only 6 inches beyond the edges of the footing.
GEGTECH
CONSULTANTS, INC.
TYPICAL FOOTING OVEREXCAVATION
1520 S 348th St. and 34713 - 16th Ave. S
Federal Way, Washington
Job No: I Date: Plate:
16584 June 2017 11
Stormwater Pollution Prevention Plan
(SWPPP)
for
Jacksons
Prepared for:
The Washington State Department of Ecology
Northwest Regional Office
3190 - 160th Avenue SE
Bellevue, WA 98008-5452
425-649-7000
Owner Operator / Contractor
PacWest Energy, LLC TBD
Project Site Location
Northwest corner of s 348th Street and S 16t" Ave
Federal Way, Washington
Certified Erosion and Sediment Control Lead (CESCL)
TBD
SWPPP Prepared By
Barghausen Consulting Engineers, Inc.
18215 - 72nd Avenue South
Kent, WA 98032
(425) 251-6222
Chris Jensen, Project Engineer
SWPPP Preparation Date
June 20, 2018
Project Construction Dates
TBD
RECEIVED
JUN 2 0 2018
CITY OF Ay
COMMUNITY D FEDERAL OPMENT
Table of Contents
1 Project Information..........................................................._...............................................
4
1.1 Existing Conditions......................................................................................................
4
1.2 Proposed Construction Activities..................................................................................
4
2 Construction Stormwater Best Management Practices(BMPs)...........................................
6
2.1 The 13 Elements..........................................................................................................
6
2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits ........................................
6
2.1.2 Element 2: Establish Construction Access............................................................
7
2.1.3 Element 3: Control Flow Rates.............................................................................
8
2.1.4 Element 4: Install Sediment Controls....................................................................
9
2.1.5 Element 5: Stabilize Soils....................................................................................10
2.1.6 Element 6: Protect Slopes....................................................................................11
2.1.7 Element 7: Protect Drain Inlets............................................................................12
2.1.8 Element 8: Stabilize Channels and Outlets..........................................................13
2.1.9 Element 9: Control Pollutants...............................................................................14
2.1.10 Element 10: Control Dewatering..........................................................................16
2.1.11 Element 11: Maintain BMPs...............................................................................
..17
2.1.12 Element 12: Manage the Project..........................................................................18
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs.................................19
3 Pollution Prevention Team.................................................................................................20
4 Monitoring and Sampling Requirements............................................................................21
4.1 Site Inspection............................................................................................................21
4.2 Stormwater Quality Sampling......................................................................................21
4.2.1 Turbidity Sampling..............................................................................................21
4.2.2 pH Sampling......................... ............................................................................
...23
5 Reporting and Record Keeping— ............................................. — ......................................
24
5.1 Record Keeping..........................................................................................................24
5.1.1 Site Log Book......................................................................................................24
5.1.2 Records Retention...............................................................................................24
5.1.3 Updating the SWPPP..........................................................................................24
5.2 Reporting....................................................................................................................25
5.2.1 Discharge Monitoring Reports..............................................................................25
5.2.2 Notification of Noncompliance..............................................................................25
P a g e 11 17764-SWPPP.docx
List of Tables
Table1 — pH -Modifying Sources............................................................................................15
Table2 — Management............................................................................................................18
Table3 — Team Information....................................................................................................20
Table 4 — Turbidity Sampling Method....................................................................................21
Table 5 — pH Sampling Method............................................................ .......23
List of Appendices
Appendix/Glossary
A. Site Map
B. BMP Detail
C. Site Inspection Form
D. Engineering Calculations
P age 12 17764-SWPPP.docx
List of Acronyms and Abbreviations
Acronym / Abbreviation Explanation
303(d)
Section of the Clean Water Act pertaining to Impaired Waterbodies
BFO
Bellingham Field Office of the Department of Ecology
BMP(s)
Best Management Practice(s)
CESCL
Certified Erosion and Sediment Control Lead
COz
Carbon Dioxide
CRO
Central Regional Office of the Department of Ecology
CSWGP
Construction Stormwater General Permit
CWA
Clean Water Act
DMR
Discharge Monitoring Report
DO
Dissolved Oxygen
Ecology
Washington State Department of Ecology
EPA
United States Environmental Protection Agency
ERO
Eastern Regional Office of the Department of Ecology
ERTS
Environmental Report Tracking System
ESC
Erosion and Sediment Control
GUILD
General Use Level Designation
NPDES
National Pollutant Discharge Elimination System
NTU
Nephelometric Turbidity Units
NWRO
Northwest Regional Office of the Department of Ecology
pH
Power of Hydrogen
RCW
Revised Code of Washington
SPCC
Spill Prevention, Control, and Countermeasure
su
Standard Units
SWMMEW
Stormwater Management Manual for Eastern Washington
SWMMWW
Stormwater Management Manual for Western Washington
SWPPP
Stormwater Pollution Prevention Plan
TESC
Temporary Erosion and Sediment Control
SWRO
Southwest Regional Office of the Department of Ecology
TMDL
Total Maximum Daily Load
VFO
Vancouver Field Office of the Department of Ecology
WAC
Washington Administrative Code
WSDOT
Washington Department of Transportation
WWHM
Western Washington Hydrology Model
P a g e 13 17764-SWPPP.docx
Project Information
Project/Site Name: Jacksons
Street/Location: Northwest corner of S 16th Ave and S 348th St.
City: Federal Way State: WA Zip code: 98003
1.1 Existing Conditions
Total acreage (including support activities such as off -site equipment staging yards, material
storage areas, borrow areas).
Total acreage: 1.05
Disturbed acreage: 1.28
Existing structures: Project site is currently developed with a gas station and auto retail.
Landscape topography: The site is largely flat with slopes ranging from 2-10 percent pervious
area.
Drainage patterns: The existing drainage patterns are such that stormwater sheet flows
towards the southwest.
Existing Vegetation: The site has some existing vegetation consisting of mostly grass and
shrubs.
Critical Areas (wetlands, streams, high
erosion risk, steep or difficult to stabilize Site is not located in nor does it contain
slopes): any critical areas worth mentioning.
1.2 Proposed Construction Activities
Description of site development (example: subdivision):
The project proposes the construction of a new Jacksons convenience store, fuel canopy, underground
fuel storage tanks, storage building trash enclosure, including new water, storm, and sewer services.
Description of construction activities (example: site preparation, demolition, excavation):
Construction activities will include clearing and grubbing existing landscape. Subsequently after
the demo phase, excavation will occur for the structure and proposed stormwater infiltration
system. Such preparation will include regrading in order to install the proposed improvements.
Description of site drainage including flow from and onto adjacent properties. Must be
consistent with Site Map in Appendix A:
The project site is higher than its adjacent road embankments on the west and south sides at the
intersection and will generally flow to the south driveway.
Runoff from 16 Ave S sheet flows to the south and west into existing catch basins and storm
drains along the east side of 16th Avenue S. The existing stormwater infrastructure within 348th
P a g e 14 17764-SWPPP.docx
Street East consists of catch basins and storm drains and flows to the west. The existing
topography of 16th Ave E is such that the road gradually slopes from north to south. There does
not appear to be any flow that will be contributed from adjacent property or road way.
Description of final stabilization (example: extent of revegetation, paving, landscaping):
Final site stabilization will include the installation of hardscapes, such as asphalt pavement and
concrete sidewalks. The developed condition of the site will retain the existing drainage pattern
and sheet flow stormwater to on -site catch basins, then into an oil/water separator before
entering a Modular Wetland and into an infiltration facility. A site map has been provided in
Appendix A. All landscaping areas will be amended per Federal Way standards.
P age 15 17764-SWPPP.docx
2 Construction Stormwater Best Management Practices (BMPs)
The SWPPP is a living document reflecting current conditions and changes throughout the life
of the project. These changes may be informal (i.e., hand-written notes and deletions). Update
the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design.
2.1 The 13 Elements
2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits
List and describe BMPs: In order to protect adjacent properties and to reduce the area of soil
exposed to construction, the limits of construction will be clearly marked and enclosed within a
construction fence prior to any land disturbing activities. This fence will encompass all areas
subject to construction, as well as delineate all areas where no construction is to take place. A
silt fence will also be placed in certain areas as shown on the accompanying Site Plan, in order
to protect the soil and vegetation outside the construction area. Refer to Appendix B:
Construction BMPs for detailed drawings of the proposed BMPs. The proposed BMPs relevant
to vegetation preservation/clearing limits are:
BMP C103: High Visibility Plastic or Metal Fence
BMP C233: Silt Fence
Installation Schedules: BMPs listed above (Silt Fence and High Visibility Plastic or Metal
Fence) will be installed prior to any land disturbing activity.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P age 16 17764-SWPPP.docx
2.1.2 Element 2: Establish Construction Access
List and describe BMPs: In order to protect the adjacent existing asphalt pavement from dirt
and debris, the project will construct a Construction Entrance according to BMP C105. See
Appendix A: Site Plan for the proposed location of the construction entrance.
Installation Schedules: Construction Entrance shall be installed prior to the commencement of
construction activities.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P age 17 17764-SWPPP.docx
2.1.3 Element 3: Control Flow Rates
Will you construct stormwater retention and/or detention facilities?
® Yes ❑ No
Will you use permanent infiltration ponds or other low impact development (example:
rain gardens, bio-retention, porous pavement) to control flow during construction?
® Yes ❑ No
List and describe BMPs: A sediment trap will be installed on the southwest side of the project
site for purposes of controlling flow rates during construction. See Appendix A for the location
of the sediment trap, Appendix B for detailed drawings of the proposed BMPs, and Appendix D
for engineering calculations for the sediment trap.
The proposed BMP relevant to flow control is:
BMP C103 240: Sediment Trap
Installation Schedules: The BMP listed above (Sediment Trap) will be installed prior to any
land disturbing activity.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P age 18 17764-SWPPP.docx
2.1.4 Element 4: Install Sediment Controls
List and describe BMPs: On -site sediment contamination shall be controlled by the
implementation of silt fences and/or straw wattles, depending on the site. Our site contains low
potential for sediment contamination and will only utilize silt fences. Silt fences will be placed in
the necessary areas where soil from the areas marked for excavation may interfere and
contaminate with soils located either off site or adjacent. See Appendix A for the location of silt
fences on site and Appendix B for detailed drawings of the proposed BMPs. The proposed
BMP that will be installed for sediment control is:
BMP C233: Silt Fence
BMP C200: Interceptor Dike and Swale
Installation Schedules: Sediment Controls will be installed prior to any land disturbance
activity.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e 19 17764-SWPPP.docx
2.1.5 Element 5: Stabilize Soils
West of the Cascade Mountains Crest
Season
Dates
Number of Days Soils Can
be Left Ex osed
During the Dry Season
May 1 — September 30
7 days
During the Wet Season
October 1 — April 30
2 days
Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on
the weather forecast.
Anticipated project dates: Start date: TBD End date: TBD
Will you construct during the wet season?
TBD
List and describe BMPs: Soils exposed and unworked for the time period specified above
shall be stabilized with the application of effective BMPs to prevent erosion throughout the
duration of the project. Soil stockpiles shall be stabilized or covered using plastic sheeting and
where possible, located away from storm inlets, waterways, and drainage channels. Refer to
Appendix B for detailed drawings of the BMPs used. The proposed BMPs specific to Soil
Stabilization are:
BMP C123: Plastic Covering
Installation Schedules: BMPs shall be implemented as soon as land disturbing activity begins
and installed where applicable for the duration of the project.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e 110 17764-SWPPP.docx
2.1.6 Element 6: Protect Slopes
Will steep slopes be present at the site during construction?
® Yes ❑ No
List and describe BMPs: All cut and fill slopes will be designed, constructed, and protected
in a manner that minimizes erosion. Temporary and permanent seeding shall be used at all
exposed areas pursuant to the prior mentioned schedule (seasonal restrictions).
Refer to Appendix B for detailed drawings of the BMPs used. The proposed BMPs specific to
Slope Protection are:
BMP C120: Temporary and Permanent Seeding
Installation Schedules: BMPs shall be implemented as soon as land disturbing activity begins
and installed where applicable for the duration of the project. Implementation of one or more of
alternative BMPs may be necessary after the first sign that existing BMPs are ineffective or
failing.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e 111 17764-SWPPP.docx
2.1.7 Element 7: Protect Drain Inlets
List and describe BMPs: All storm drain inlets, both existing and those installed during
construction must be protected to prevent unfiltered or untreated water from entering the
drainage conveyance system. However, the first priority is to keep all access roads clean of
sediment and keep water from washing streets separate from entering storm drains until
treatment can be provided. Storm Drain Inlet Protection will be implemented for all drainage
inlets and culverts that could potentially be impacted by sediment -laden runoff on or near the
project site. This includes inlets and culverts located offsite. Inlet protection devices shall be
cleaned and replaced or removed when sediment has filled a third of the available storage
(unless a different standard is specified by the product manufacturer). The following inlet
protection measures will be proposed for this project:
BMP C220: Storm Drain Inlet Protection
Installation Schedules: Storm Drain Inlet Protection will be provided at the start of the project
and will be maintained for the duration of the project.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e 112 17764-SWPPP.docx
2.1.8 Element 8: Stabilize Channels and Outlets
Provide stabilization, including armoring material, adequate to prevent erosion of outlets,
adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all
conveyance systems.
List and describe BMPs: The project site is located west of the Cascade Mountain Crest. As
such, were there are any temporary on -site conveyance channels, they shall be designed,
constructed, and stabilized to prevent erosion from the expected peak 10-minute velocity of flow
from a Type 1A, 10-year, 24-hour recurrence interval storm for the developed condition. An on -
site sediment trap is proposed for this project along with a temporary conveyance channel,
therefore an Outlet Control BMP is proposed. The following inlet protection measures will be
proposed for this project:
• BMP C209: Outlet Protection
Installation Schedules: Outlet Protection will be provided at the start of the project and will be
maintained for the duration of the project.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e 113 17764-SWPPP.docx
2.1.9 Element 9: Control Pollutants
List and describe BMPs: All pollutants, including waste materials and demolition debris, that
occur on site will be handled and disposed of in a manner that does not cause contamination of
stormwater. Good housekeeping and preventative measures will be taken to ensure that the
site will be kept clean, well -organized, and free of debris. The following BMPs will be
implemented:
• All vehicles, equipment, and petroleum product storage/dispensing areas will be
inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent
leaks or spills.
• In order to perform emergency repairs on site, temporary plastic will be placed beneath
and, if raining, over the vehicle.
• Any chemicals stored in the construction areas will conform to the appropriate source
control BMPs listed in Volume IV of the Ecology stormwater manual. All chemicals shall have
cover, containment, and protection provided on site, pursuant to BMP C153 for Material
Delivery, Storage and Containment.
Proposed BMPs applicable to Pollutant Control:
• BMP C140: Dust Control
• BMP C151: Concrete Handling
• BMP C 152: Sawcutting and Surface Pollution Prevention
• BMP C154: Concrete Washout Area
Installation Schedules: BMPs shall be installed as necessary to control pollutants for the
duration of construction.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on -site?
❑ Yes ® No
Will wheel wash or tire bath system BMPs be used during construction?
® Yes ❑ No
Will pH -modifying sources be present on -site?
® Yes ❑ No
P a g e 114 17764-SWPPP.docx
Table 1 — pH -Modifying Sources
❑
None
®
Bulk cement
Cement kiln dust
❑
Fly ash
❑
Other cementitious materials
❑
j New concrete washing or curing waters
❑
Waste streams generated from concrete grinding and sawing
❑
Exposed aggregate processes
❑
Dewatering concrete vaults
❑
Concrete pumping and mixer washout waters
❑
Recycled concrete
❑
Recycled concrete stockpiles
❑
Other (i.e., calcium lignosulfate) [please describe: ]
Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches,
streets, or streams. Excess concrete must not be dumped on -site, except in designated
concrete washout areas with appropriate BMPs installed.
Will uncontaminated water from water -only based shaft drilling for construction of building, road,
and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits
discharge to surface waters?
❑ Yes ® No
P a g e 115 17764-SWPPP.docx
2.1.10 Element 10: Control Dewatering
Discharge clean, non -turbid de -watering water, such as well -point groundwater, to
systems tributary to, or directly into surface waters of the state, as specified in Element
No. 8, provided the de -watering flow does not cause erosion or flooding of receiving
waters or interfere with the operation of the system. Do not route clean dewatering
water through stormwater sediment ponds. Note that "surface waters of the state" may
exist on a construction site as well as off site; for example, a creek running through a
site.
• Highly turbid or contaminated dewatering water shall be handled separately from
stormwater.
Clean, non -turbid dewatering water, such as well -point ground water, can be discharged
to systems tributary to, or directly into surface waters of the state, provided the
dewatering flow does not cause erosion or flooding of receiving waters. Clean
dewatering water should not be routed through stormwater sediment ponds.
Other dewatering disposal options may include:
o Transport off site in a vehicle, such as a vacuum flush truck, for legal disposal in
a manner that does not pollute state waters.
o Infiltration.
o Ecology -approved on -site chemical treatment or other suitable treatment
technologies.
o Sanitary sewer discharge with local sewer district approval, if there is no other
option.
o Use of a sedimentation bag with outfall to a ditch or swale for small volumes of
localized dewatering.
The project may exhibit high groundwater elevations. Depending on the time of year,
dewatering activities may occur during the installation of on -site stormwater conveyance
systems and/or excavation activities.
Installation Schedules: Dewatering controls will be installed prior to any significant excavation
activities.
Inspection and Maintenance plan: TBD
Responsible Staff: TBD
P a g e 116 17764-SWPPP.docx
2.1.11 Element 11: Maintain BMPs
All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained
and repaired as needed to ensure continued performance of their intended function.
Maintenance and repair shall be conducted in accordance with each particular BMP
specification (see 2016 King County Stormwater Manual).
Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar
week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the
site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to
once every calendar month.
All temporary ESC BMPs shall be removed within 30 days after final site stabilization is
achieved or after the temporary BMPs are no longer needed.
Trapped sediment shall be stabilized on -site or removed. Disturbed soil resulting from removal
of either BMPs or vegetation shall be permanently stabilized.
Additionally, protection must be provided for all BMPs installed for the permanent control of
stormwater from sediment and compaction. BMPs that are to remain in place following
completion of construction shall be examined and restored to full operating condition. If
sediment enters these BMPs during construction, the sediment shall be removed and the facility
shall be returned to conditions specified in the construction documents.
P a g e 117 17764-SWPPP.docx
2.1.12 Element 12: Manage the Project
The project will be managed based on the following principles:
■ Projects will be phased to the maximum extent practicable and seasonal work limitations
will be taken into account.
Inspection and monitoring:
o Inspection, maintenance and repair of all BMPs will occur as needed to ensure
performance of their intended function.
o Site inspections and monitoring will be conducted in accordance with Special
Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map.
Sampling station(s) are located in accordance with applicable requirements of
the CSWGP.
■ Maintain an updated SWPPP.
o The SWPPP will be updated, maintained, and implemented in accordance with
Special Conditions S3, S4, and S9 of the CSWGP.
As site work progresses the SWPPP will be modified routinely to reflect changing site
conditions. The SWPPP will be reviewed monthly to ensure the content is current.
Table 2 — Management
®
Design the project to fit the existing topography, soils, and drainage patterns
®
Emphasize erosion control rather than sediment control
®
Minimize the extent and duration of the area exposed
®
Keep runoff velocities low
®
Retain sediment on -site
®
Thoroughly monitor site and maintain all ESC measures
®
Schedule major earthwork during the dry season
❑
Other (please describe)
P a g e 118 17764-SWPPP.docx
2.1.13 Element 13: Protect Low Impact Development (LID) BMPs
The project does not propose any Low Impact Development BMPs to be implemented as part of
this proposal.
P a g e 119 17764-SWPPP.docx
Pollution Prevention Team
Table 3 — Team Information
Title
Names
Phone Number
Certified Erosion and
Sediment Control Lead
(CESCL)
TBD
TBD
Resident Engineer
Chris Jensen, P.E.
(425) 251-6222
Emergency Ecology
Contact
Staff on Duty
(425) 649-7130
Emergency Permittee/
Owner Contact
TBD
TBD
Non -Emergency Owner
Contact
TBD
TBD
Monitoring Personnel
TBD
TBD
Ecology Regional Office
Southwest Regional Office
(360) 407-6300
P a g e 120 17764-SWPPP.docx
4 Monitoring and Sampling Requirements
Monitoring includes visual inspection, sampling for water quality parameters of concern, and
documentation of the inspection and sampling findings in a site log book. A site log book will be
maintained for all on -site construction activities and will include:
• A record of the implementation of the SWPPP and other permit requirements
• Site inspections
■ Stormwater sampling data
The site log book must be maintained on -site within reasonable access to the site and be made
available upon request to Ecology or the local jurisdiction.
Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See
CSWGP Special Condition S8 and Section 5 of this template.
4.1 Site Inspection
Site inspections will be conducted at least once every calendar week and within 24 hours
following any discharge from the site. For sites that are temporarily stabilized and inactive, the
required frequency is reduced to once per calendar month.
The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with
the applicable requirements of the CSWGP.
4.2 Stormwater Quality Sampling
4.2.1 Turbidity Sampling
Requirements include calibrated turbidity meter or transparency tube to sample site discharges
for compliance with the CSWGP. Sampling will be conducted at all discharge points at least
once per calendar week.
Method for sampling turbidity:
Table 4 — Turbidity Sampling Method
U
Turbidity Meter/Turbid i meter (required for disturbances 5 acres or greater in size)
®
Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size)
The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency
less than 33 centimeters.
If the discharge's turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to
or greater than 6 cm, the following steps will be conducted:
1. Review the SWPPP for compliance with Special Condition S9. Make appropriate
revisions within 7 days of the date the discharge exceeded the benchmark.
P a g e 121 17764-SWPPP.docx
2. Immediately begin the process to fully implement and maintain appropriate source
control and/or treatment BMPs as soon as possible. Address the problems within 10
days of the date the discharge exceeded the benchmark. If installation of necessary
treatment BMPs is not feasible within 10 days, Ecology may approve additional time
when the Permittee requests an extension within the initial 10-day response period.
3. Document BMP implementation and maintenance in the site log book.
If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following
steps will be conducted:
1. Telephone or submit an electronic report to the applicable Ecology Region's
Environmental Report Tracking System (ERTS) within 24 hours.
• Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis,
Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 or
http:l/www.ecy.wa.gov/programs/spills/forms/nerts online/SWRO nerts online.html
2. Immediately begin the process to fully implement and maintain appropriate source
control and/or treatment BMPs as soon as possible. Address the problems within 10
days of the date the discharge exceeded the benchmark. If installation of necessary
treatment BMPs is not feasible within 10 days, Ecology may approve additional time
when the Permittee requests an extension within the initial 10-day response period
3. Document BMP implementation and maintenance in the site log book.
4. Continue to sample discharges daily until one of the following is true:
• Turbidity is 25 NTU (or lower).
• Transparency is 33 cm (or greater).
• Compliance with the water quality limit for turbidity is achieved.
0 1 - 5 NTU over background turbidity, if background is less than 50 NTU
0 1 % - 10% over background turbidity, if background is 50 NTU or greater
■ The discharge stops or is eliminated.
P a g e 122 17764-SWPPP.docx
4.2.2 pH Sampling
pH monitoring is required for "Significant concrete work" (i.e., greater than 1000 cubic yards
poured concrete over the life of the project). The use of recycled concrete or engineered soils
(soil amendments including but not limited to Portland cement -treated base [CTB], cement kiln
dust [CKD] or fly ash) also requires pH monitoring.
For significant concrete work, pH sampling will start the first day concrete is poured and
continue until it is cured, typically three (3) weeks after the last pour.
For engineered soils and recycled concrete, pH sampling begins when engineered soils or
recycled concrete are first exposed to precipitation and continues until the area is fully
stabilized.
If the measured pH is 8.5 or greater, the following measures will be taken:
1. Prevent high pH water from entering storm sewer systems or surface water.
2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate
technology such as carbon dioxide (CO2) sparging (liquid or dry ice).
3. Written approval will be obtained from Ecology prior to the use of chemical treatment
other than CO2 sparging or dry ice.
Method for sampling pH:
Table 5 — pH Sampling Method
❑
H meter
®
H test kit
❑
Wide range pH indicator paper
P a g e 123 17764-SWPPP.docx
5 Reporting and Record Keeping
5.1 Record Keeping
5.1.1 Site Log Book
A site log book will be maintained for all on -site construction activities and will include:
A record of the implementation of the SWPPP and other permit requirements
• Site inspections
• Sample logs
5.1.2 Records Retention
Records will be retained during the life of the project and for a minimum of three (3) years
following the termination of permit coverage in accordance with Special Condition S5.0 of the
CSWGP.
Permit documentation to be retained on -site:
• CSWGP
• Permit Coverage Letter
• SWPPP
• Site Log Book
Permit documentation will be provided within 14 days of receipt of a written request from
Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when
requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP.
5.1.3 Updating the SWPPP
The SWPPP will be modified if:
• Found ineffective in eliminating or significantly minimizing pollutants in stormwater
discharges from the site.
• There is a change in design, construction, operation, or maintenance at the construction
site that has, or could have, a significant effect on the discharge of pollutants to waters
of the State.
The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine
additional or modified BMPs are necessary for compliance. An updated timeline for BMP
implementation will be prepared.
P a g e 124 17764-SWPPP.docx
5.2 Reporting
5.2.1 Discharge Monitoring Reports
Cumulative soil disturbance is less than one (1) acre; therefore, Discharge Monitoring
Reports (DMRs) will not be submitted to Ecology because water quality sampling is not being
conducted at the site.
5.2.2 Notification of Noncompliance
If any of the terms and conditions of the permit is not met, and the resulting noncompliance may
cause a threat to human health or the environment, the following actions will be taken:
1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable
Regional office ERTS phone number (Regional office numbers listed below).
2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or
correct the noncompliance. If applicable, sampling and analysis of any noncompliance
will be repeated immediately and the results submitted to Ecology within five (5) days of
becoming aware of the violation.
3. A detailed written report describing the noncompliance will be submitted to Ecology
within five (5) days, unless requested earlier by Ecology.
Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6
cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as
required by Special Condition S5.A of the CSWGP.
■ Southwest Region at (360) 407-6300 for Clallam, Clark, Cowlitz, Grays Harbor,
Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, or Wahkiakum
Include the following information:
1. Your name and / Phone number
2.
Permit number
3.
City / County of project
4.
Sample results
5.
Date / Time of call
6.
Date / Time of sample
7.
Project name
In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will
be notified if chemical treatment other than COz sparging is planned for adjustment of high pH
water.
P a g e 125 17764-SWPPP.docx
Appendix/Glossary
A. Site Map
P a g e 126 17764-SWPPP.docx
JACKSONS FOOD STORE #636 - FEDERAL WA Y, WA
NE 114 OF 5E 114 OF SEC. 20, TWN, 21 N, RGE. 4E, W. M.
KING COUNTY WASHINGTON
1n-20'
o�maN CALLvurs TESC AND DEMOLITION PLAN
� ��
f—
I. DEMOLISH EXISTING CONCRETE AND/OR ASPHALT AND DISPOSE OF OFF -SITE --
2. DEMOLISH EXISTING BUILDING AND APPURTENANCES AND DISPOSE OF OFF-51TE
DEMOLITION OF BUILDING PER SEPARATE PERMIT.
3. DEMOLISH EXISTING CURB AND DISPOSE OF OFF -SITE (FTP)_
4, DEMOLISH EXISTING ELECTRICAL SERVICE LINE AND APPURTENANCES. COORDINATE
EXTENTS OF WORK AND SCOPE OF WORK WITH PURVEYOR AND MEP PLANS
5. E(ISIING STORM LINE AND APPURTENANCES TO REMAIN AND BE PROTECTED DIJRNG
CONSTRUCTION
6 TEMPORAP.'f CONSTRUCTION FENCE (6` HIGH CHAIN LINK). FIELD VERIFY AND
GO NFIRM EXACT LOCATION WITH OWNER,
7. TEMPORARY SITE ACCESS GATE (6' HIGH CHAIN LINK WITH LOCKING DEVICE); FIELD
VERIFY AND CONFIRM EXACT LOCATIONI WITH OWNER,
S EXISTING STORM LINE AND APPURTENANCES TO BE REMOVED/ABANDONED PER
COUNTY STANDARDS CONTRACTOR TO CONFIRM. ORIGIN OF ANY AND ALL STORM
DRAINS PRIOR TO DEMOLITION IF SERVICE IS ACTIVE FOR OFF -SITE DRAINAGE AND
MUST REMAIN, CONTACT BARGHAUSEN CONSULTING ENGINEERS IIJC FOR FURTHER
DIRECTION,
:l
9 REMOVE EXISTING TREE AND DISPOSE OF OFF -SITE. (TYF)
10, DEMOLISH EXISTING SANITAR'i SEWER SERVICE LINE AS SHOWN AN[
APPURTENANCES AND DISPOSE OF OFF -SITE
11. EXISTING MAILBOX AND CONCRETE PAD TO REMAIN AND TO BE PROTECTED DURING
CONSTRUCTION
12 DEMO FISTING TRASH ENCLOSURE AND DISPOSE OFF -SITE
13 DEMOLISH EXISTING LOT LIGHT AND DISPOSE OFF -SITE
14. EXISTING TREE TO REMAIN AND TO BE PROTECTED.
15 EXISTING SIDEWALK TO REM4114 AND TO BE PROTECTED DURING CONSTRUCTION
ACTIVITIES
16 OFMO FXISTIII f: COIJCRFTF FIIFI]NC. PACT AND FXISTIN!. fANf1Pf
17. REMOVE/ABANDON EXISTING FUEL STORAGE TANKS AND APPURTENANCES AND
DISPOSE OFF -SITE PER EPA STANDARDS CONTRACTOR TO OBTAIN DESIGN AND
PERMIT FOR SHORING IF NECESSARY FOR EXCAVATION OF EXISTING UNDERGROUND
STORAGE TANKS (TIP-)-
18, DEMO LISTING VACUUM AND DISPOSE OF OFF -SITE. COORDINATE WITH OWNER,
PRIOR TO REMOVAL. SALVAGE EOUIPMENT AT OWNERS DISCRETION,
19. REMOVE EXISTING BOLLARDS AND DISPOSE OF OFF -SITE. (TYP)
20. REMOVE EXISTING AIR/WATER. UNIT AIJD DISPOSE OF OFF -SITE.
21 APPROXIMATE SAWCUT LIMITS, SAWCUT IN A SMOOTH, STRAIGHT, AND CONTINUOUS
LINE.
22 DEMO EXISTING FUEL DISPENSERS AND FUEL ISLAND. COORDIIATE WITH OWNER
PRIOR TO REMOVAL, SALVAGE EQUIPMENT AT OWNERS DISCRETION
23 DEMO EXISTING ELECTRICAL METER AND APPURTENANCES. CONTRACTOR TO C014FIRM
ORIGIN OF ELECTRICAL LINES PRIOR TO REMOVAL AND COORDINATE WITH
OWNER/PURVEYOR PRIOR TO DEMO.
24. REMOVE PORTION OF EXISTING GAS SERVICE AS SHOWN AND CAP EXISTING END.
COORDINATE EXTENTS AND SCOPE OF WORT: WITH PURVEYOR.
25. EXISTING MONITORING WELL TO REMAIIJ AND TO BE PROTECTED DUPING
CONSTRUCTION SEE MONITORING NOTE THIS SHEET (TYP),
26. EXISTING ELECTRICAL SERVICE TO REMAIN AND TO BE PROTECTED DURING
CONSTRUCTION.
27 WORR ON ADJACENT PROPERTY, COORDINATE 'WORK AND EASEMEIJT WITH OWNER
PRIOR TO WORK ON ADJACENT PROPERTY
28 PROTECT PROPOSED LOCATION OF LID BMP FROM COMPETITION DUPING
CONSTRUCTION ACTIVITIES,
29 DEMO EXISTING FENCE AND GUARDRAIL AND DISPOSE OFF -SITE.
30. REMOVE PROPANE TANK AND SALVAGE AS DIRECTED 81' OWNER
31. REMOVE EXISTING FLAG POLE AND DISPOSE OFF -SITE,
32. RELOCATE EXISTING FIRE H(ORANT,
33. DEMO EXISTING CHAIIJL114K FENCE AND DISPOSE OFF -SITE.
®
TCMPOOAOY INLCT DCDIIACIIT
PROTECTION
SILT FENCE
LIMITS OF DISTURBANCE
CONSTRUCTION ENTRANCE
ASPHALT TO BE REMOVED
+ 1 -;•11T
CONCRETE TO BE REMOVED
CURB TO BE REMOVED
_
TEMPORARY CONSTRUCTION FENCE
O° * TREE/SHRUBS TO BE REMOVED
V
S 348TH ST
STORMTECHITAW EXCAVATION NOTE
STOPMTECH/TANY. EXCAVATIONS SHALL BE PER OSHA REQUIREMENTS AND BE PERFORMED
FOLLOWING THE RECOMMENDATIONS OF THE SOILS REPORT. TANK EXCAVATIONS THAT REQUIRE
SHORING SHALL BE ENGINEERED AND PERMITTED SEPARATELY AND SHALL BE THE RESPONSIBILITY
OF THE INSTALUNG CONTRACTOR
MONrrORING WELL NOTE:
FEDERAL WAY REVISED CODE NOTE:
MODIFICATION OF ANY EXISTING MONITORING WELL
PER FWRC 19.145.2 C.I-II, FILL MATERIAL SHALL NOT CONTAIN CONCENTRATION OF CONTAMINANTS THAT
MUST BE COORDINATED WITH JACKSCNS/SHELL MONITORING
EXCEED CLEANUP STANDARDS FOR SOIL AS SPECIFIED IN THE MODEL TOXICS CONTROL ACT, AN IMPORTED
WELL PROGRAM. ALL EXISTING MONRORING WELLS SHOWN TO
FILL SOURCE STATEMENT IS REQUIRED FOR ALL PROJECTS WHERE MORE THAN 100 CUBIC YARDS OF FILL
BE REMOVED OR ABANDONED SHALL BE PER DOE STANDARDS
WILL BE IMPORTED TO A SITE THE CITY MAI' REOUIRE ANALYTICAL RESULTS TO DEMONSTRATE THAT FILL
GENERAL CONTRACTOR SHALL PROVICE A LICE14SED DRILL
MATERIALS DO HOT EXCEED CLEANUP STANDARDS THE IMPORTED FILL SOURCE STATEMENT SHALL INCLUDE:
CONTRACTOR TO APPLY FOR NA.L W/D.O, E. TO DECOMMISSION
(0 SOURCE LOCATION OF IMPORTED FILL;
WELL AND SUBMIT PROOF OF COMPLETED ABANDONMENT PRIOR
(6) PREVIOUS LAUD USES OF THE SOURCE LOCATION
TO OCCUPANCY/PERMIT FINAL
041
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APPROXIMATE
LIMITS OF DISTURBANCE
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® EROSION CONTROL CALLOUTS:
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I CONTRACTOR TO INSTALL SILT FENCE AR UIJD PERIMETER OF SITE AS
� I� LJ.J p m
7j
NECESSARY TO PREVENT SILT -LADEN RUNDFF FROM LEAVING SITE, AND AS
- mC6
DIRECTED By CITY INSPECTOR. SEE DETAIL t jC3.1.
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CONTRACTOR TO INSTALL TEMPORARY INLET SEDIMENT PROTECTION!
- AT ALL
I_ N
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EXISTING AND PROPOSED CATCH BASINS AS NECESSARY TO REVENT
F-.
C,—
SILT -LADEN WATER FROM ENTERING STORM DRAINAGE SYSTEM. COORDINATE
PLACEMENT WITH PROPERTY OWNERS AND AS DIRECTED BY CITY INSPECTOR,
O =O
SEE DETAIL 2/C31.
Q CU C,
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i APPROXIMATE LOCATION OF CONSTRUCTION STAGING AREA, CONTRACTOR TO USE
Q aD
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THIS AREA FOP. TEMPORARY STOCKPILE STORAGE NJD CONCRETE WASHOUT.
ADJUST SIZE AND LOCATION OF AREA AS NEEDED DUPING CONSTRUCTION
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A. CONTRACTOR TO INSTALL TEMPORARY STABILIZED CONSTRUCTION ENTRANCE
U) N
PAD PER COUNTY STANDARDS SEE DETAIL 5/C3. 1,
Y O L
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5 APPROXIMATE LOCATION OF TEMPORARY SEDIMENT TRAP. CONTRACTOR TO
QU w
INSTALL TEMPORARY SEDIMENT TRAP. CONTRACTOR, TO GRADE TO SEDIMENT TW
'V,-DITCH
CD
AND PROVIDE AS NECESSARY SEE DETAIL 3/C3.1,
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6 APPROXIMATE LOCATION OF TEMPORARY'%I DITCH SEE DETAIL 4/C3 I,
LL
SURVEY MONUMENT NOTE:
C014TRACTOR SHALL BE FULLY RESPONSIBLE FOR OBTAINING PERMITS FROM THE
WASHINGTON STATE DEPARTMENT OF NATURAL RESOURCES FOR REMOVING AND
REPLACING AL SURVEY M N M NTATI N THAT MAY AFFECTED
L O U E 0 A M BE BY CONSTRUCTION
ACTIVITY, PURSUANT TO WAG 332-120 APPLICATIONS MUST BE COMPLETED BY A
REGISTERED LAND SURVEYOR APPLICATIONS FOR PERMITS TO REMOVE MONUMENTS
MAY BE OBTAINED FROM THE WASHINGTON STATE DEPARTMEN- OF NATURAL
RESOURCES, OR BY CONTACTING THEIR. OFFICE BY TELEPHONE AT (206) 90'-1190
WASHINGTON STATE DEPARTMENT OF NATURAL RESOURCES
PUBLIC LAND SURVEY OFFICE
Ill1 WASHINGTON STREET S E.
P 0. BOX 47060
OLYMPIA, WASHINGTON 96504-7060
UPON COMPLETION OF CONSTRUCTION, ALL MONUMENTS DISPLACED, REMOVED. OR
DESTROYED SHALL BE REPLACED BY A REGISTERED LAND SURVEYOR, AT THE COST AND
AT THE DIRECTION OF THE CONTRACTOR. PURSUANT TO THES= REGULATIONS THE
APPROPRIATE FORMS FOR REPLACEMENT OF SAID MONUMENTATION SHALL ALSO BE THE
RESPONSIBILITY OF THE CONTRACTOR
CONSTRUCTION SCHEDULE:,RYs
1 FLAG ALL WOFK LIMITS
2. CALL THE USA UNDERGROUND SERVICE ALERT TO VERIFY LOCATION
OF ANY EXISTING UTILITIES TWO (2) WORKING DAYS PRIOR TO START
OF CONSTP.UCTION
3 NOTIFY SEDIMENT CONTROL INSPECTOR TWENTY-FOUR (24) HOURS
'fSX�kAL i64+
PRIOR. TO START OF CONSTRUCTION
6/5i 16
4 IDENTIFY AND PROTECT ALL EXISTING VEGETATION TO REMAIN
5 PERFORM CLEARING MID GRADING REQURED FOR INSTALLATION OF
S-
PEP.IMETER CONTROLS
-
6 INSTALL PERIMETER RUNOFF CONTROLS; NOTIFY SEDIMENT CONTROL
s
INSPECTOR AND OBTAIN APPROVAL BEFORE PROCEEDING FURTHER.
7 INSTALL STORM DRAINAGE PROTECTION
Fill vj
B CLEAR. AND STABILIZE CONSTRUCTION ACCESS
1 9 `7jl
9 COMPLETE ALL REQUIRED STOCKPILING SITE CLEARING, AND GRADING.
- -
10 APPLY TEMPORARY OR PERMANENT STABILIZATION MEASURES
IMMEDIATELY ON ALL DISTURBED AREAS WHERE WORK, MAY BE
DELAYED OR 15 COMPLETE DO NOT LEAVE LARGE AREAS
=
UNPROTECTED FOR MORE THAN SEVEN (7) DAYS
_
1 I INSTALL UNDERGROUND STORAGE TANK'_, BUILDING FOUNDATIONS,
O�
g w
INSTALL SITE UTILITIES, AND PARKING LOT BASE
w a a
12 WEATHER -IN BUILDING
z
Z
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5
13 COMPLETE PARKING LOT CONSTRUCTION
< O N 5
rn_ z
li. COMPLETE FINAL GRADING, STABILIZATION AND �NDSCAFING
G tt
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15 GOPFl SEDIMENT CONTROL INSPECTOR AND O6?MITI APPROVAL TO
I I
-
REMOVE SEDIMENT AND EROSION CONTROL MEASURES
N N Z r
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D Know what's below.
0 Call before you dig.
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Dial 911
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1
PERMIT NO, 16— 105763-00—PC
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1PPROVED
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B. BMP Detail
•
BMP C103:
High Visibility Plastic or Metal Fence
•
BMP C105:
Stabilized Construction Entrance / Exit
•
BMP C120:
Temporary and Permanent Seeding
•
BMP C123:
Plastic Covering
•
BMP C140:
Dust Control
•
BMP C150:
Materials on Hand
■
BMP C151:
Concrete Handling
•
BMP C152:
Sawcutting and Surfacing Pollution Prevention
•
BMP C153:
Material Delivery, Storage and Containment
•
BMP C154:
Concrete Washout Area
•
BMP C160:
Certified Erosion and Sediment Control Lead
•
BMP C162:
Scheduling
■
BMP C200:
Interceptor Dike and Swale
■
BMP C209:
Outlet Protection
•
BMP C220:
Storm Drain Inlet Protection
•
BMP C233:
Silt Fence
•
BMP C240:
Sediment Trap
P a g e 128 17764-SWPPP.docx
BMP C103: High Visibility Fence
Purpose
Fencing is intended to:
1. Restrict clearing to approved limits.
2. Prevent disturbance of sensitive areas, their buffers, and other areas required
to be left undisturbed.
3. Limit construction traffic to designated construction entrances, exits, or
internal roads.
4. Protect areas where marking with survey tape may not provide adequate
protection.
Conditions of Use
To establish clearing limits plastic, fabric, or metal fence may be used:
• At the boundary of sensitive areas, their buffers, and other areas required to be
left uncleared.
• As necessary to control vehicle access to and on the site.
Design and Installation Specifications
High visibility plastic fence shall be composed of a high -density polyethylene material
and shall be at least four feet in height. Posts for the fencing shall be steel or wood and
placed every 6 feet on center (maximum) or as needed to ensure rigidity. The fencing
shall be fastened to the post every six inches with a polyethylene tie. On long
continuous lengths of fencing, a tension wire or rope shall be used as a top stringer to
prevent sagging between posts. The fence color shall be high visibility orange. The
fence tensile strength shall be 360 lbs./ft. using the ASTM D4595 testing method.
If appropriate install fabric silt fence in accordance with BMP C233: Silt Fence (p.367) to
act as high visibility fence. Silt fence shall be at least 3 feet high and must be highly
visible to meet the requirements of this BMP.
Metal fences shall be designed and installed according to the manufacturer's
specifications.
Metal fences shall be at least 3 feet high and must be highly visible.
Fences shall not be wired or stapled to trees.
Maintenance Standards
If the fence has been damaged or visibility reduced, it shall be repaired or replaced
immediately and visibility restored.
P a g e 129 17764-SWPPP.docx
BMP C105: Stabilized Construction Entrance / Exit
Purpose
Stabilized Construction entrances are established to reduce the amount of sediment
transported onto paved roads by vehicles or equipment. This is done by constructing a
stabilized pad of quarry spalls at entrances and exits for construction sites.
Conditions of Use
Construction entrances shall be stabilized wherever traffic will be entering or leaving a
construction site if paved roads or other paved areas are within 1,000 feet of the site.
For residential construction provide stabilized construction entrances for each
residence, rather than only at the main subdivision entrance. Stabilized surfaces shall
be of sufficient length/width to provide vehicle access/parking, based on lot
size/configuration.
On large commercial, highway, and road projects, the designer should include enough
extra materials in the contract to allow for additional stabilized entrances not shown in
the initial Construction SWPPP. It is difficult to determine exactly where access to these
projects will take place; additional materials will enable the contractor to install them
where needed.
Design and Installation Specifications
See Figure II-4.1.1 Stabilized Construction Entrance (p.273) for details. Note: the 100'
minimum length of the entrance shall be reduced to the maximum practicable size when
the size or configuration of the site does not allow the full length (100').
Construct stabilized construction entrances with a 12-inch thick pad of 4-inch to 8-inch
quarry spalls, a 4-inch course of asphalt treated base (ATB), or use existing pavement.
Do not use crushed concrete, cement, or calcium chloride for construction entrance
stabilization because these products raise pH levels in stormwater and concrete
discharge to surface waters of the State is prohibited.
A separation geotextile shall be placed under the spalls to prevent fine sediment from
pumping up into the rock pad. The geotextile shall meet the following standards:
Grab Tensile Strength (ASTM D4751)
200 psi min.
Grab Tensile Elongation (ASTM D4632)
30% max.
Mullen Burst Strength (ASTM D3786-80a)
400 psi min.
AOS (ASTM D4751)
20-45 (U.S. standard sieve size)
• Consider early installation of the first lift of asphalt in areas that will paved; this
can be used as a stabilized entrance. Also consider the installation of excess
concrete as a stabilized entrance. During large concrete pours, excess concrete
is often available for this purpose.
• Fencing (see BMP C103: High Visibility Fence (p.269)) shall be installed as
necessary to restrict traffic to the construction entrance.
P a g e 130 17764-SWPPP.docx
• Whenever possible, the entrance shall be constructed on a firm, compacted
subgrade. This can substantially increase the effectiveness of the pad and
reduce the need for maintenance.
• Construction entrances should avoid crossing existing sidewalks and back of
walk drains if at all possible. If a construction entrance must cross a sidewalk or
back of walk drain, the full length of the sidewalk and back of walk drain must be
covered and protected from sediment leaving the site.
Maintenance Standards
Quarry spalls shall be added if the pad is no longer in accordance with the
specifications.
• If the entrance is not preventing sediment from being tracked onto pavement,
then alternative measures to keep the streets free of sediment shall be used.
This may include replacement/cleaning of the existing quarry spalls, street
sweeping, an increase in the dimensions of the entrance, or the installation of a
wheel wash.
• Any sediment that is tracked onto pavement shall be removed by shoveling or
street sweeping. The sediment collected by sweeping shall be removed or
stabilized on site. The pavement shall not be cleaned by washing down the
street, except when high efficiency sweeping is ineffective and there is a threat to
public safety. If it is necessary to wash the streets, the construction of a small
sump to contain the wash water shall be considered. The sediment would then
be washed into the sump where it can be controlled.
• Perform street sweeping by hand or with a high efficiency sweeper. Do not use a
non -high efficiency mechanical sweeper because this creates dust and throws
soils into storm systems or conveyance ditches.
• Any quarry spalls that are loosened from the pad, which end up on the roadway
shall be removed immediately.
• If vehicles are entering or exiting the site at points other than the construction
entrance(s), fencing (see BMP C103) shall be installed to control traffic.
• Upon project completion and site stabilization, all construction accesses intended
as permanent access for maintenance shall be permanently stabilized.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C105:
Stabilized Construction Entrance / Exit. The products did not pass through the
Technology Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may
choose not to accept this product approved as equivalent, or may require additional
testing prior to consideration for local use. The products are available for review on
Ecology's website at
http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equ ivalent. htmI
P a g e 131 17764-SWPPP.docx
BMP C120: Temporary and Permanent Seeding
Purpose
Seeding reduces erosion by stabilizing exposed soils. A well -established vegetative
cover is one of the most effective methods of reducing erosion.
Conditions of Use
Use seeding throughout the project on disturbed areas that have reached final grade or
that will remain unworked for more than 30 days.
The optimum seeding windows for western Washington are April 1 through June 30 and
September 1 through October 1.
Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is
established.
Between October 1 and March 30 seeding requires a cover of mulch with straw or an
erosion control blanket until 75 percent grass cover is established.
Review all disturbed areas in late August to early September and complete all seeding
by the end of September. Otherwise, vegetation will not establish itself enough to
provide more than average protection.
Mulch is required at all times for seeding because it protects seeds from heat,
moisture loss, and transport due to runoff. Mulch can be applied on top of the
seed or simultaneously by hydroseeding. See BMP C121: Mulching (p.284) for
specifications.
Seed and mulch, all disturbed areas not otherwise vegetated at final site stabilization.
Final stabilization means the completion of all soil disturbing activities at the site and the
establishment of a permanent vegetative cover, or equivalent permanent stabilization
measures (such as pavement, riprap, gabions, or geotextiles) which will prevent
erosion.
Design and Installation Specifications
Seed retention/detention ponds as required.
Install channels intended for vegetation before starting major earthwork and hydroseed
with a Bonded Fiber Matrix. For vegetated channels that will have high flows, install
erosion control blankets over hydroseed. Before allowing water to flow in vegetated
channels, establish 75 percent vegetation cover. If vegetated channels cannot be
established by seed before water flow; install sod in the channel bottom —over
hydromulch and erosion control blankets.
• Confirm the installation of all required surface water control measures to prevent
seed from washing away.
• Hydroseed applications shall include a minimum of 1,500 pounds per acre of
mulch with 3 percent tackifier. See BMP C121: Mulching (p.284) for
specifications.
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Areas that will have seeding only and not landscaping may need compost or
mealbased mulch included in the hydroseed in order to establish vegetation. Re-
install native topsoil on the disturbed soil surface before application.
When installing seed via hydroseeding operations, only about 1/3 of the seed
actually ends up in contact with the soil surface. This reduces the ability to
establish a good stand of grass quickly. To overcome this, consider increasing
seed quantities by up to 50 percent.
Enhance vegetation establishment by dividing the hydromulch operation into two
phases:
1. Phase 1- Install all seed and fertilizer with 25-30 percent
mulch and tackifier onto soil in the first lift.
2. Phase 2- Install the rest of the mulch and tackifier over the
first lift.
Or, enhance vegetation by:
1. Installing the mulch, seed, fertilizer, and tackifier in one lift.
2. Spread or blow straw over the top of the hydromulch at a rate of 800-1000 pounds
per acre.
3. Hold straw in place with a standard tackifier.
Both of these approaches will increase cost moderately but will greatly improve and
enhance vegetative establishment. The increased cost may be offset by the reduced
need for:
• Irrigation.
• Reapplication of mulch.
• Repair of failed slope surfaces.
This technique works with standard hydromulch (1,500 pounds per acre minimum) and
BFM/MBFMs (3,000 pounds per acre minimum).
Seed may be installed by hand if:
o Temporary and covered by straw, mulch, or topsoil.
o Permanent in small areas (usually less than 1 acre) and covered with
mulch, topsoil, or erosion blankets.
o The seed mixes listed in the tables below include recommended mixes for
both temporary and permanent seeding.
o Apply these mixes, with the exception of the wetland mix, at a rate of 120
pounds per acre. This rate can be reduced if soil amendments or slow
release fertilizers are used.
o Consult the local suppliers or the local conservation district for their
recommendations because the appropriate mix depends on a variety of
factors, including location, exposure, soil type, slope, and expected foot
traffic. Alternative seed mixes approved by the local authority may be
used.
o Other mixes may be appropriate, depending on the soil type and
hydrology of the area.
Table II-4.1.2 Temporary Erosion Control Seed Mix (p.280) lists the standard mix
for areas requiring a temporary vegetative cover.
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Table II-4.1.2 Temporary Erosion Control Seed Mix
% Weight %Purity % Germination
Chewings or annual blue grass
Festuca rubra var. commutata or Poa anna
40 98 90
Perennial rye
Lolium perenne
50 98 90
Redtop or colonial bentgrass
Agrostis alba or Agrostis tenuis
5 92 85
White dutch clover
Trifolium repens
5 98 90
Table II-4.1.3 Landscaping Seed Mix (p.281) lists a recommended mix for
landscaping seed.
Table II-4.1.3 Landscaping Seed Mix
% Weight % Purity % Germination
Perennial rye blend
Lolium perenne
70 98 90
Chewings and red fescue blend
Festuca rubra var. commutata
or Festuca rubra
30 98 90
Table 11-4.1.4 Low -Growing Turf Seed Mix (p.281) lists a turf seed mix for dry
situations where there is no need for watering. This mix requires very little
maintenance.
Table II-4.1.4 Low -Growing Turf Seed Mix
% Weight % Purity % Germination
Dwarf tall fescue (several varieties)
Festuca arundinacea var.
45 98 90
Dwarf perennial rye (Barclay)
Lolium perenne var. barclay
30 98 90
Red fescue
Festuca rubra
20 98 90
Colonial bentgrass
Agrostis tenuis
Page 135
5 98 90
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Table II-4.1.5 Bioswale Seed Mix* (p.281) lists a mix for bioswales and other
intermittently wet areas.
Table II-4.1.5 Bioswale Seed Mix*
% Weight % Purity % Germination
Tall or meadow fescue
Festuca arundinacea or Festuca elatior
75-80 98 90
Seaside/Creeping bentgrass
Agrostis palustris
10-15 92 85
Redtop bentgrass
Agrostis a/ba or Agrostis gigantea
5-10 90 80
* Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix
Table II-4.1.6 Wet Area Seed Mix* (p.282) lists a low -growing, relatively non-invasive
seed mix appropriate for very wet areas that are not regulated wetlands. Apply this
mixture at a rate of 60 pounds per acre. Consult Hydraulic Permit Authority
(HPA) for seed mixes if applicable.
Table II-4.1.6 Wet Area Seed Mix*
% Weight
% Purity
% Germination
Tall or meadow fescue
Festuca arundinacea or Festuca elatior
60-70
98
90
Seaside/Creeping bentgrass
Agrostis palustris
10-15
98
85
Meadow foxtail
A/epocurus pratensis
10-15
90
80
Alsike clover
Trifolium hybridum
1-6
98
90
Redtop bentgrass
Agrostis albs
1-6
92
85
* Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix
Table II-4.1.7 Meadow Seed Mix (p.282) lists a recommended meadow seed mix
for infrequently maintained areas or non -maintained areas where colonization by
native plants is desirable. Likely applications include rural road and utility right -of
way. Seeding should take place in September or very early October in order to
obtain adequate establishment prior to the winter months. Consider the
appropriateness of clover, a fairly invasive species, in the mix. Amending the soil
can reduce the need for clover.
P a g e 136 17764-SWPPP.docx
Table II-4.1.7 Meadow Seed Mix
% Weight % Purity % Germination
Redtop or Oregon bentgrass
Agrostis albs or Agrostis oregonensis
20 92 85
Red fescue
Festuca rubra
70 98 90
White dutch clover
Trifolium repens
10 98 90
Roughening and Rototilling:
o The seedbed should be firm and rough. Roughen all soil no matter what
the slope. Track walk slopes before seeding if engineering purposes
require compaction. Backblading or smoothing of slopes greater than
4H:1 V is not allowed if they are to be seeded.
o Restoration -based landscape practices require deeper incorporation than
that provided by a simple single -pass rototilling treatment. Wherever
practical, initially rip the subgrade to improve long-term permeability,
infiltration, and water inflow qualities. At a minimum, permanent areas
shall use soil amendments to achieve organic matter and permeability
performance defined in engineered soil/landscape systems. For systems
that are deeper than 8 inches complete the rototilling process in multiple
lifts, or prepare the engineered soil system per specifications and place to
achieve the specified depth.
Fertilizers:
o Conducting soil tests to determine the exact type and quantity of fertilizer
is recommended. This will prevent the over -application of fertilizer.
o Organic matter is the most appropriate form of fertilizer because it
provides nutrients (including nitrogen, phosphorus, and potassium) in the
least watersoluble form.
o In general, use 10-4-6 N-P-K (nitrogen -phosphorus -potassium) fertilizer at
a rate of 90 pounds per acre. Always use slow -release fertilizers because
they are more efficient and have fewer environmental impacts. Do not add
fertilizer to the hydromulch machine, or agitate, more than 20 minutes
before use. Too much agitation destroys the slow -release coating.
o There are numerous products available that take the place of chemical
fertilizers. These include several with seaweed extracts that are beneficial
to soil microbes and organisms. If 100 percent cottonseed meal is used as
the mulch in hydroseed, chemical fertilizer may not be necessary.
Cottonseed meal provides a good source of long-term, slow -release,
available nitrogen.
Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix:
o On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded
Fiber Matrix (MBFM) products. Apply BFM/MBFM products at a minimum
rate of 3,000 pounds per acre of mulch with approximately 10 percent
tackifier. Achieve a minimum of 95 percent soil coverage during
application. Numerous products are available commercially. Installed
P a g e 137 17764-SWPPP.docx
products per manufacturer's instructions. Most products require 24-36
hours to cure before rainfall and cannot be installed on wet or saturated
soils. Generally, products come in 40-50 pound bags and include all
necessary ingredients except for seed and fertilizer.
BFMs and MBFMs provide good alternatives to blankets in most areas requiring
vegetation establishment. Advantages over blankets include:
o BFM and MBFMs do not require surface preparation.
o Helicopters can assist in installing BFM and MBFMs in remote areas.
o On slopes steeper than 2.5H:lV, blanket installers may require ropes and
harnesses for safety.
o Installing BFM and MBFMs can save at least $1,000 per acre compared
to blankets.
Maintenance Standards
Reseed any seeded areas that fail to establish at least 80 percent cover (100 percent
cover for areas that receive sheet or concentrated flows). If reseeding is ineffective, use
an alternate method such as sodding, mulching, or nets/blankets. If winter weather
prevents adequate grass growth, this time limit may be relaxed at the discretion of the
local authority when sensitive areas would otherwise be protected.
o Reseed and protect by mulch any areas that experience erosion after
achieving adequate cover. Reseed and protect by mulch any eroded area.
o Supply seeded areas with adequate moisture, but do not water to the
extent that it causes runoff.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C120:
Temporary and Permanent Seeding. The products did not pass through the Technology
Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to
accept this product approved as equivalent, or may require additional testing prior to
consideration for local use. The products are available for review on Ecology's website
at hftp://www.ecy.wa.gov/programs/wq/stormwater/newtech/equiva lent. html.
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BMP C123: Plastic Covering
Purpose
Plastic covering provides immediate, short-term erosion protection to slopes and
disturbed areas.
Conditions of Use
Plastic covering may be used on disturbed areas that require cover measures for less
than 30 days, except as stated below.
• Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note:
The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable
for long-term (greater than six months) applications.
• Due to rapid runoff caused by plastic covering, do not use this method upslope of
areas that might be adversely impacted by concentrated runoff. Such areas
include steep and/or unstable slopes.
• Plastic sheeting may result in increased runoff volumes and velocities, requiring
additional on -site measures to counteract the increases. Creating a trough with
wattles or other material can convey clean water away from these areas.
• To prevent undercutting, trench and backfill rolled plastic covering products.
■ While plastic is inexpensive to purchase, the added cost of installation,
maintenance, removal, and disposal make this an expensive material, up to
$1.50-2.00 per square yard.
• Whenever plastic is used to protect slopes install water collection measures at
the base of the slope. These measures include plastic -covered berms, channels,
and pipes used to covey clean rainwater away from bare soil and disturbed
areas. Do not mix clean runoff from a plastic covered slope with dirty runoff from
a project.
• Other uses for plastic include:
o Temporary ditch liner.
o Pond liner in temporary sediment pond.
o Liner for bermed temporary fuel storage area if plastic is not reactive to
the type of fuel being stored.
o Emergency slope protection during heavy rains.
o Temporary drainpipe ("elephant trunk") used to direct water.
Design and Installation Specifications
• Plastic slope cover must be installed as follows:
1. Run plastic up and down slope, not across slope.
2. Plastic may be installed perpendicular to a slope if the slope length is less
than 10 feet.
3. Minimum of 8-inch overlap at seams.
4. On long or wide slopes, or slopes subject to wind, tape all seams.
5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top
of the slope and backfill with soil to keep water from flowing underneath.
6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and
tie them together with twine to hold them in place.
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7. Inspect plastic for rips, tears, and open seams regularly and repair
immediately. This prevents high velocity runoff from contacting bare soil
which causes extreme erosion.
8. Sandbags may be lowered into place tied to ropes. However, all sandbags
must be staked in place.
Plastic sheeting shall have a minimum thickness of 0.06 millimeters.
If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable
protection shall be installed at the toe of the slope in order to reduce the velocity
of runoff.
Maintenance Standards
Torn sheets must be replaced and open seams repaired.
® Completely remove and replace the plastic if it begins to deteriorate due to
ultraviolet radiation.
Completely remove plastic when no longer needed.
® Dispose of old tires used to weight down plastic sheeting appropriately.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C123: Plastic
Covering. The products did not pass through the Technology Assessment Protocol —
Ecology (TAPE) process. Local jurisdictions may choose not to accept this product
approved as equivalent, or may require additional testing prior to consideration for local
use. The products are available for review on Ecology's website at
http://www. ecy. wa . oov/programs/wa/stormwater/newtech/eclu iya lent. htm I
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BMP C140: Dust Control
Purpose
Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways,
drainage ways, and surface waters.
Conditions of Use
In areas (including roadways) subject to surface and air movement of dust where on -
site and off -site impacts to roadways, drainage ways, or surface waters are likely.
Design and Installation Specifications
■ Vegetate or mulch areas that will not receive vehicle traffic. In areas where
planting, mulching, or paving is impractical, apply gravel or landscaping rock.
■ Limit dust generation by clearing only those areas where immediate activity will
take place, leaving the remaining area(s) in the original condition. Maintain the
original ground cover as long as practical.
• Construct natural or artificial windbreaks or windscreens. These may be
designed as enclosures for small dust sources.
■ Sprinkle the site with water until surface is wet. Repeat as needed. To prevent
carryout of mud onto street, refer to BMP C105: Stabilized Construction Entrance
Exit (p.270)
• Irrigation water can be used for dust control. Irrigation systems should be
installed as a first step on sites where dust control is a concern.
• Spray exposed soil areas with a dust palliative, following the manufacturer's
instructions and cautions regarding handling and application. Used oil is
prohibited from use as a dust suppressant. Local governments may approve
other dust palliatives such as calcium chloride or PAM.
■ PAM (BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection (p.300))
added to water at a rate of 0.5 lbs. per 1,000 gallons of water per acre and
applied from a water truck is more effective than water alone. This is due to
increased infiltration of water into the soil and reduced evaporation. In addition,
small soil particles are bonded together and are not as easily transported by
wind. Adding PAM may actually reduce the quantity of water needed for dust
control. Use of PAM could be a cost-effective dust control method.
Techniques that can be used for unpaved roads and lots include:
• Lower speed limits. High vehicle speed increases the amount of dust stirred up
from unpaved roads and lots.
• Upgrade the road surface strength by improving particle size, shape, and mineral
types that make up the surface and base materials.
• Add surface gravel to reduce the source of dust emission. Limit the amount of
fine particles (those smaller than .075 mm) to 10 to 20 percent.
• Use geotextile fabrics to increase the strength of new roads or roads undergoing
reconstruction.
• Encourage the use of alternate, paved routes, if available.
P a g e 141 17764-SWPPP.docx
• Restrict use of paved roadways by tracked vehicles and heavy trucks to prevent
damage to road surface and base.
• Apply chemical dust suppressants using the admix method, blending the product
with the top few inches of surface material. Suppressants may also be applied as
surface treatments.
■ Pave unpaved permanent roads and other trafficked areas.
• Use vacuum street sweepers.
■ Remove mud and other dirt promptly so it does not dry and then turn into dust.
• Limit dust -causing work on windy days.
• Contact your local Air Pollution Control Authority for guidance and training on
other dust control measures. Compliance with the local Air Pollution Control
Authority constitutes compliance with this BMP.
Maintenance Standards
Respray area as necessary to keep dust to a minimum.
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BMP C150: Materials on Hand
Purpose
Keep quantities of erosion prevention and sediment control materials on the project site
at all times to be used for regular maintenance and emergency situations such as
unexpected heavy summer rains. Having these materials on -site reduces the time
needed to implement BMPs when inspections indicate that existing BMPs are not
meeting the Construction SWPPP requirements. In addition, contractors can save
money by buying some materials in bulk and storing them at their office or yard.
Conditions of Use
• Construction projects of any size or type can benefit from having materials on
hand. A small commercial development project could have a roll of plastic and
some gravel available for immediate protection of bare soil and temporary berm
construction. A large earthwork project, such as highway construction, might
have several tons of straw, several rolls of plastic, flexible pipe, sandbags,
geotextile fabric and steel "T" posts.
• Materials are stockpiled and readily available before any site clearing, grubbing,
or earthwork begins. A large contractor or developer could keep a stockpile of
materials that are available for use on several projects.
■ If storage space at the project site is at a premium, the contractor could maintain
the materials at their office or yard. The office or yard must be less than an hour
from the project site.
Design and Installation Specifications
Depending on project type, size, complexity, and length, materials and quantities will
vary. A good minimum list of items that will cover numerous situations includes:
Material
■ Clear Plastic, 6 mil
• Drainpipe, 6 or 8 inch diameter
• Sandbags, filled
• Straw Bales for mulching,
■ Quarry Spalls
• Washed Gravel
■ Geotextile Fabric
• Catch Basin Inserts
• Steel "T" Posts
• Silt fence material
• Straw Wattles
Maintenance Standards
• All materials with the exception of the quarry spalls, steel "T" posts, and gravel
should be kept covered and out of both sun and rain.
■ Re -stock materials used as needed.
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BMP C151: Concrete Handling
Purpose
Concrete work can generate process water and slurry that contain fine particles and
high pH, both of which can violate water quality standards in the receiving water.
Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use
this BMP to minimize and eliminate concrete, concrete process water, and concrete
slurry from entering waters of the state.
Conditions of Use
Any time concrete is used, utilize these management practices. Concrete construction
projects include, but are not limited to, the following:
• Curbs
■ Sidewalks
• Roads
• Bridges
■ Foundations
• Floors
• Runways
Design and Installation Specifications
• Assure that washout of concrete trucks, chutes, pumps, and internals is
performed at an approved off -site location or in designated concrete washout
areas. Do not wash out concrete trucks onto the ground, or into storm drains,
open ditches, streets, or streams. Refer to BMP C154: Concrete Washout Area
(p.317) for information on concrete washout areas.
• Return unused concrete remaining in the truck and pump to the originating batch
plant for recycling. Do not dump excess concrete on site, except in designated
concrete washout areas.
• Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats,
and trowels into formed areas only.
■ Wash equipment difficult to move, such as concrete pavers in areas that do not
directly drain to natural or constructed stormwater conveyances.
® Do not allow washdown from areas, such as concrete aggregate driveways, to
drain directly to natural or constructed stormwater conveyances.
• Contain washwater and leftover product in a lined container when no formed
areas are available. Dispose of contained concrete in a manner that does not
violate ground water or surface water quality standards.
o Always use forms or solid barriers for concrete pours, such as pilings, within 15-
feet of surface waters.
■ Refer to BMP C252: High pH Neutralization Using CO2 (p.409) and BMP C253:
pH Control for High pH Water (p.412) for pH adjustment requirements.
• Refer to the Construction Stormwater General Permit for pH monitoring
requirements if the project involves one of the following activities:
o Significant concrete work (greater than 1,000 cubic yards poured concrete
or recycled concrete used over the life of a project).
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o The use of engineered soils amended with (but not limited to) Portland
cement -treated base, cement kiln dust or fly ash.
o Discharging stormwater to segments of water bodies on the 303(d) list
(Category 5) for high pH.
Maintenance Standards
Check containers for holes in the liner daily during concrete pours and repair the same
day.
P age 145 17764-SWPPP.docx
BMP C152: Sawcutting and Surfacing Pollution Prevention
Purpose
Sawcutting and surfacing operations generate slurry and process water that contains
fine particles and high pH (concrete cutting), both of which can violate the water quality
standards in the receiving water. Concrete spillage or concrete discharge to surface
waters of the State is prohibited. Use this BMP to minimize and eliminate process water
and slurry created through sawcutting or surfacing from entering waters of the State.
Conditions of Use
Utilize these management practices anytime sawcutting or surfacing operations take
place. Sawcutting and surfacing operations include, but are not limited to, the following:
• Sawing
• Coring
• Grinding
• Roughening
• Hydro -demolition
• Bridge and road surfacing
Design and Installation Specifications
• Vacuum slurry and cuttings during cutting and surfacing operations.
• Slurry and cuttings shall not remain on permanent concrete or asphalt pavement
overnight.
• Slurry and cuttings shall not drain to any natural or constructed drainage
conveyance including stormwater systems. This may require temporarily blocking
catch basins.
• Dispose of collected slurry and cuttings in a manner that does not violate ground
water or surface water quality standards.
• Do not allow process water generated during hydro -demolition, surface
roughening or similar operations to drain to any natural or constructed drainage
conveyance including stormwater systems. Dispose process water in a manner
that does not violate ground water or surface water quality standards.
• Handle and dispose cleaning waste material and demolition debris in a manner
that does not cause contamination of water. Dispose of sweeping material from a
pick-up sweeper at an appropriate disposal site.
Maintenance Standards
Continually monitor operations to determine whether slurry, cuttings, or process water
could enter waters of the state. If inspections show that a violation of water quality
standards could occur, stop operations and immediately implement preventive
measures such as berms, barriers, secondary containment, and vacuum trucks.
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BMP C153: Material Delivery, Storage and Containment
Purpose
Prevent, reduce, or eliminate the discharge of pollutants to the stormwater system or
watercourses from material delivery and storage. Minimize the storage of hazardous
materials on -site, store materials in a designated area, and install secondary
containment.
Conditions of Use
These procedures are suitable for use at all construction sites with delivery and
storage of the following materials:
• Petroleum products such as fuel, oil and grease
• Soil stabilizers and binders (e.g., Polyacrylamide)
• Fertilizers, pesticides and herbicides
• Detergents
■ Asphalt and concrete compounds
• Hazardous chemicals such as acids, lime, adhesives, paints, solvents, and
curing compounds
• Any other material that may be detrimental if released to the environment
Design and Installation Specifications
The following steps should be taken to minimize risk:
■ emporary storage area should be located away from vehicular traffic, near the
construction entrance(s), and away from waterways or storm drains.
• Material Safety Data Sheets (MSDS) should be supplied for all materials stored.
Chemicals should be kept in their original labeled containers.
• Hazardous material storage on -site should be minimized.
• Hazardous materials should be handled as infrequently as possible.
• During the wet weather season (Oct 1 — April 30), consider storing materials in a
covered area.
• Materials should be stored in secondary containments, such as earthen dike,
horse trough, or even a children's wading pool for non -reactive materials such as
detergents, oil, grease, and paints. Small amounts of material may be
secondarily contained in "bus boy" trays or concrete mixing trays.
• Do not store chemicals, drums, or bagged materials directly on the ground. Place
these items on a pallet and, when possible, and within secondary containment.
• If drums must be kept uncovered, store them at a slight angle to reduce ponding
of rainwater on the lids to reduce corrosion. Domed plastic covers are
inexpensive and snap to the top of drums, preventing water from collecting.
Material Storage Areas and Secondary Containment Practices:
• Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or
302 shall be stored in approved containers and drums and shall not be overfilled.
Containers and drums shall be stored in temporary secondary containment
facilities.
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• Temporary secondary containment facilities shall provide for a spill containment
volume able to contain 10% of the total enclosed container volume of all
containers, or 110% of the capacity of the largest container within its boundary,
whichever is greater.
• Secondary containment facilities shall be impervious to the materials stored
therein for a minimum contact time of 72 hours.
• Secondary containment facilities shall be maintained free of accumulated
rainwater and spills. In the event of spills or leaks, accumulated rainwater and
spills shall be collected and placed into drums. These liquids shall be handled as
hazardous waste unless testing determines them to be non -hazardous.
• Sufficient separation should be provided between stored containers to allow for
spill cleanup and emergency response access.
• During the wet weather season (Oct 1 — April 30), each secondary containment
facility shall be covered during non -working days, prior to and during rain events.
• Keep material storage areas clean, organized and equipped with an ample
supply of appropriate spill clean-up material (spill kit).
• The spill kit should include, at a minimum:
0 1-Water Resistant Nylon Bag
0 3-Oil Absorbent Socks 3" x 4'
o 2-Oil Absorbent Socks 3" x 10'
o 12-Oil Absorbent Pads 17"x19"
0 1-Pair Splash Resistant Goggles
0 3-Pair Nitrile Gloves
0 10-Disposable Bags with Ties
o Instructions
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BMP C154: Concrete Washout Area
Purpose
Prevent or reduce the discharge of pollutants to stormwater from concrete waste by
conducting washout off -site, or performing on -site washout in a designated area to
prevent pollutants from entering surface waters or ground water.
Conditions of Use
Concrete washout area best management practices are implemented on construction
projects where:
■ Concrete is used as a construction material
■ It is not possible to dispose of all concrete wastewater and washout off -site
(ready mix plant, etc.).
• Concrete trucks, pumpers, or other concrete coated equipment are washed on -
site.
■ Note: If less than 10 concrete trucks or pumpers need to be washed out on -site,
the washwater may be disposed of in a formed area awaiting concrete or an
upland disposal site where it will not contaminate surface or ground water. The
upland disposal site shall be at least 50 feet from sensitive areas such as storm
drains, open ditches, or water bodies, including wetlands.
Design and Installation Specifications
Implementation
The following steps will help reduce stormwater pollution from concrete wastes:
• Perform washout of concrete trucks at an approved off -site location or in
designated concrete washout areas only.
■ Do not wash out concrete trucks onto the ground, or into storm drains, open
ditches, streets, or streams.
• Do not allow excess concrete to be dumped on -site, except in designated
concrete washout areas.
• Concrete washout areas may be prefabricated concrete washout containers, or
self -installed structures (above -grade or below -grade).
• Prefabricated containers are most resistant to damage and protect against spills
and leaks. Companies may offer delivery service and provide regular
maintenance and disposal of solid and liquid waste.
• If self -installed concrete washout areas are used, below -grade structures are
preferred over above -grade structures because they are less prone to spills and
leaks.
■ Self -installed above -grade structures should only be used if excavation is not
practical.
Education
• Discuss the concrete management techniques described in this BMP with the
ready -mix concrete supplier before any deliveries are made.
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Educate employees and subcontractors on the concrete waste management
techniques described in this BMP.
Arrange for contractor's superintendent or Certified Erosion and Sediment
Control Lead (CESCL) to oversee and enforce concrete waste management
procedures.
A sign should be installed adjacent to each temporary concrete washout facility
to inform concrete equipment operators to utilize the proper facilities.
Contracts
Incorporate requirements for concrete waste management into concrete supplier and
subcontractor agreements.
Location and Placement
• Locate washout area at least 50 feet from sensitive areas such as storm drains,
open ditches, or water bodies, including wetlands.
• Allow convenient access for concrete trucks, preferably near the area where the
concrete is being poured.
• If trucks need to leave a paved area to access washout, prevent track -out with a
pad of rock or quarry spalls (see BMP C105: Stabilized Construction Entrance /
Exit (p.270)). These areas should be far enough away from other construction
traffic to reduce the likelihood of accidental damage and spills.
• The number of facilities you install should depend on the expected demand for
storage capacity.
■ On large sites with extensive concrete work, washouts should be placed in
multiple locations for ease of use by concrete truck drivers.
On -site Temporary Concrete Washout Facility, Transit Truck Washout
Procedures:
• Temporary concrete washout facilities shall be located a minimum of 50 feet from
sensitive areas including storm drain inlets, open drainage facilities, and
watercourses. See Figure II-4.1.7a Concrete Washout Area (p.322), Figure II-
4.1.7b Concrete Washout Area (p.323), and Figure II-4.1.8 Prefabricated
Concrete Washout Container w/Ramp (p.324).
• Concrete washout facilities shall be constructed and maintained in sufficient
quantity and size to contain all liquid and concrete waste generated by washout
operations.
• Washout of concrete trucks shall be performed in designated areas only.
• Concrete washout from concrete pumper bins can be washed into concrete
pumper trucks and discharged into designated washout area or properly
disposed of off -site.
• Once concrete wastes are washed into the designated area and allowed to
harden, the concrete should be broken up, removed, and disposed of per
applicable solid waste regulations. Dispose of hardened concrete on a regular
basis.
0 Temporary Above -Grade Concrete Washout Facility
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Temporary concrete washout facility (type above grade) should be constructed
as shown on the details below, with a recommended minimum length and
minimum width of 10 ft, but with sufficient quantity and volume to contain all liquid
and concrete waste generated by washout operations.
• Plastic lining material should be a minimum of 10 mil polyethylene sheeting and
should be free of holes, tears, or other defects that compromise the
impermeability of the material.
• Temporary Below -Grade Concrete Washout Facility.
• Temporary concrete washout facilities (type below grade) should be constructed
as shown on the details below, with a recommended minimum length and
minimum width of 10 ft. The quantity and volume should be sufficient to contain
all liquid and concrete waste generated by washout operations.
® Lath and flagging should be commercial type.
® Plastic lining material shall be a minimum of 10 mil polyethylene sheeting and
should be free of holes, tears, or other defects that compromise the
impermeability of the material.
• Liner seams shall be installed in accordance with manufacturers'
recommendations.
• Soil base shall be prepared free of rocks or other debris that may cause tears
® or holes in the plastic lining material.
Maintenance Standards
Inspection and Maintenance
• Inspect and verify that concrete washout BMPs are in place prior to the
commencement of concrete work.
■ During periods of concrete work, inspect daily to verify continued performance.
o Check overall condition and performance.
o Check remaining capacity (% full).
o If using self -installed washout facilities, verify plastic liners are intact and
sidewalls are not damaged.
o If using prefabricated containers, check for leaks.
• Washout facilities shall be maintained to provide adequate holding capacity with
a minimum freeboard of 12 inches.
• Washout facilities must be cleaned, or new facilities must be constructed and
ready for use once the washout is 75% full.
• If the washout is nearing capacity, vacuum and dispose of the waste material in
an approved manner.
• Do not discharge liquid or slurry to waterways, storm drains or directly onto
ground.
• Do not use sanitary sewer without local approval.
• Place a secure, non -collapsing, non -water collecting cover over the concrete
washout facility prior to predicted wet weather to prevent accumulation and
overflow of precipitation.
• Remove and dispose of hardened concrete and return the structure to a
functional condition. Concrete may be reused on -site or hauled away for disposal
or recycling.
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• When you remove materials from the self -installed concrete washout, build a new
structure; or, if the previous structure is still intact, inspect for signs of weakening
or damage, and make any necessary repairs. Re -line the structure with new
plastic after each cleaning.
Removal of Temporary Concrete Washout Facilities
■ When temporary concrete washout facilities are no longer required for the work,
the hardened concrete, slurries and liquids shall be removed and properly
disposed of.
• Materials used to construct temporary concrete washout facilities shall be
removed from the site of the work and disposed of or recycled.
• Holes, depressions or other ground disturbance caused by the removal of the
temporary concrete washout facilities shall be backfilled, repaired, and stabilized
to prevent erosion.
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BMP C160: Certified Erosion and Sediment Control Lead
Purpose
The project proponent designates at least one person as the responsible representative
in charge of erosion and sediment control (ESC), and water quality protection. The
designated person shall be the Certified Erosion and Sediment Control Lead (CESCL)
who is responsible for ensuring compliance with all local, state, and federal erosion and
sediment control and water quality requirements.
Conditions of Use
A CESCL shall be made available on projects one acre or larger that discharge
stormwater to surface waters of the state. Sites less than one acre may have a person
without CESCL certification conduct inspections; sampling is not required on sites that
disturb less than an acre.
The CESCL shall:
M
Have a current certificate proving attendance in an erosion and sediment control
training course that meets the minimum ESC training and certification
requirements established by Ecology (see details below). Ecology will maintain a
list of ESC training and certification providers at:
http://www.ecy.wa.gov/programs/wq/stormwater/cescl.html
• Be a Certified Professional in Erosion and Sediment Control (CPESC); for
additional information go to: http://www.envirocertinti.org/cpesc/
Specifications
• Certification shall remain valid for three years.
■ The CESCL shall have authority to act on behalf of the contractor or developer
and shall be available, or on -call, 24 hours per day throughout the period of
construction.
• The Construction SWPPP shall include the name, telephone number, fax
number, and address of the designated CESCL.
■ A CESCL may provide inspection and compliance services for multiple
construction projects in the same geographic region.
Duties and responsibilities of the CESCL shall include, but are not limited to the
following:
• Maintaining permit file on site at all times which includes the Construction
SWPPP and any associated permits and plans.
• Directing BMP installation, inspection, maintenance, modification, and removal.
■ Updating all project drawings and the Construction SWPPP with changes made.
• Completing any sampling requirements including reporting results using
WebDMR.
• Keeping daily logs, and inspection reports. Inspection reports should include:
o Inspection date/time.
o Weather information; general conditions during inspection and
approximate amount of precipitation since the last inspection. A summary
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or list of all BMPs implemented, including observations of all
erosion/sediment control structures or practices. The following shall be
noted:
• Locations of BMPs inspected.
• Locations of BMPs that need maintenance.
• Locations of BMPs that failed to operate as designed or intended
■ Locations of where additional or different BMPs are required.
o Visual monitoring results, including a description of discharged
stormwater.
o The presence of suspended sediment, turbid water, discoloration, and oil
sheen shall be noted, as applicable.
o Any water quality monitoring performed during inspection.
o General comments and notes, including a brief description of any BMP
repairs, maintenance or installations made as a result of the inspection.
o Facilitate, participate in, and take corrective actions resulting from
inspections performed by outside agencies or the owner.
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BMP C162: Scheduling
Purpose
Sequencing a construction project reduces the amount and duration of soil exposed to
erosion by wind, rain, runoff, and vehicle tracking.
Conditions of Use
The construction sequence schedule is an orderly listing of all major land -disturbing
activities together with the necessary erosion and sedimentation control measures
planned for the project. This type of schedule guides the contractor on work to be done
before other work is started so that serious erosion and sedimentation problems can be
avoided.
Following a specified work schedule that coordinates the timing of land -disturbing
activities and the installation of control measures is perhaps the most cost-effective way
of controlling erosion during construction. The removal of surface ground cover leaves a
site vulnerable to accelerated erosion. Construction procedures that limit land clearing
provide timely installation of erosion and sedimentation controls, and restore protective
cover quickly can significantly reduce the erosion potential of a site.
Design Considerations
• Minimize construction during rainy periods.
• Schedule projects to disturb only small portions of the site at any one time.
Complete grading as soon as possible. Immediately stabilize the disturbed
portion before grading the next portion. Practice staged seeding in order to
revegetate cut and fill slopes as the work progresses.
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BMP C200: Interceptor Dike and Swale
Purpose
Provide a ridge of compacted soil, or a ridge with an upslope swale, at the top or base
of a disturbed slope or along the perimeter of a disturbed construction area to convey
stormwater. Use the dike and/or swale to intercept the runoff from unprotected areas
and direct it to areas where erosion can be controlled. This can prevent storm runoff
from entering the work area or sediment -laden runoff from leaving the construction site.
Conditions of Use
Where the runoff from an exposed site or disturbed slope must be conveyed to an
erosion control facility which can safely convey the stormwater.
• Locate upslope of a construction site to prevent runoff from entering disturbed
area.
When placed horizontally across a disturbed slope, it reduces the amount and
velocity of runoff flowing down the slope.
Locate downslope to collect runoff from a disturbed area and direct water to a
sediment basin.
Design and Installation Specifications
• Dike and/or swale and channel must be stabilized with temporary or permanent
vegetation or other channel protection during construction.
• Channel requires a positive grade for drainage; steeper grades require channel
protection and check dams.
• Review construction for areas where overtopping may occur.
• Can be used at top of new fill before vegetation is established.
• May be used as a permanent diversion channel to carry the runoff.
• Sub -basin tributary area should be one acre or less.
• Design capacity for the peak volumetric flow rate calculated using a 10-minute
time step from a 10-year, 24-hour storm, assuming a Type 1A rainfall distribution,
for temporary facilities. Alternatively, use 1.6 times the 10-year, 1-hour flow
indicated by an approved continuous runoff model. For facilities that will also
serve on a permanent basis, consult the local government's drainage
requirements.
Interceptor dikes shall meet the following criteria:
• Top Width: 2 feet minimum.
• Height: 1.5 feet minimum on berm.
• Side Slope: 2H:1 V or flatter.
• Grade: Depends on topography, however, dike system minimum is 0.5%, and
maximum is 1 %.
• Compaction: Minimum of 90 percent ASTM D698 standard proctor.
• Horizontal Spacing of Interceptor Dikes:
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Average Slope
20H:1 V or less
(10 to 20)H:1 V
(4 to 10)H:1 V
(2 to 4)H:1 V
Slope Percent
3-5%
5-10%
10-25%
25-50%
Flowpath Length
300 feet
200 feet
100 feet
50 feet
• Stabilization: depends on velocity and reach
• Slopes <5%: Seed and mulch applied within 5 days of dike construction (see
BMP C121: Mulching (p.284)).
• Slopes 5 - 40%: Dependent on runoff velocities and dike materials. Stabilization
should be done immediately using either sod or riprap or other measures to avoid
erosion.
• The upslope side of the dike shall provide positive drainage to the dike outlet. No
erosion shall occur at the outlet. Provide energy dissipation measures as
necessary. Sediment -laden runoff must be released through a sediment trapping
facility.
• Minimize construction traffic over temporary dikes. Use temporary cross culverts
for channel crossing.
Interceptor swales shall meet the following criteria:
• Bottom Width: 2 feet minimum; the cross-section bottom shall be level.
• Depth: 1-foot minimum.
• Side Slope: 2H:1V or flatter.
• Grade: Maximum 5 percent, with positive drainage to a suitable outlet (such as a
sediment pond).
• Stabilization: Seed as per BMP C120: Temporary and Permanent Seeding
(p.278), BMP C202: Channel Lining (p.338), 12 inches thick riprap pressed into
the bank and extending at least 8 inches vertical from the bottom.
Inspect diversion dikes and interceptor swales once a week and after every rainfall.
Immediately remove sediment from the flow area.
Damage caused by construction traffic or other activity must be repaired before the end
of each working day.
Check outlets and make timely repairs as needed to avoid gully formation. When the
area below the temporary diversion dike is permanently stabilized, remove the dike and
fill and stabilize the channel to blend with the natural surface.
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BMP C209: Outlet Protection
Purpose
Outlet protection prevents scour at conveyance outlets and minimizes the potential for
downstream erosion by reducing the velocity of concentrated stormwater flows.
Conditions of Use
Outlet protection is required at the outlets of all ponds, pipes, ditches, or other
conveyances, and where runoff is conveyed to a natural or manmade drainage feature
such as a stream, wetland, lake, or ditch.
Design and Installation Specifications
The receiving channel at the outlet of a culvert shall be protected from erosion by rock
lining a minimum of 6 feet downstream and extending up the channel sides a minimum
of 1—foot above the maximum tailwater elevation or 1-foot above the crown, whichever
is higher. For large pipes (more than 18 inches in diameter), the outlet protection lining
of the channel is lengthened to four times the diameter of the culvert.
• Standard wingwalls, and tapered outlets and paved channels should also be
considered when appropriate for permanent culvert outlet protection. (See
WSDOT Hydraulic Manual, available through WSDOT Engineering Publications).
• Organic or synthetic erosion blankets, with or without vegetation, are usually
more effective than rock, cheaper, and easier to install. Materials can be chosen
using manufacturer product specifications. ASTM test results are available for
most products and the designer can choose the correct material for the expected
flow.
• With low flows, vegetation (including sod) can be effective.
• The following guidelines shall be used for riprap outlet protection:
1. If the discharge velocity at the outlet is less than 5 fps (pipe slope less
than 1 percent), use 2-inch to 8-inch riprap. Minimum thickness is 1-foot.
2. For 5 to 10 fps discharge velocity at the outlet (pipe slope less than 3
percent), use 24-inch to 48-inch riprap. Minimum thickness is 2 feet.
3. For outlets at the base of steep slope pipes (pipe slope greater than 10
percent), an engineered energy dissipater shall be used.
Filter fabric or erosion control blankets should always be used under riprap to
prevent scour and channel erosion.
New pipe outfalls can provide an opportunity for low-cost fish habitat
improvements. For example, an alcove of low -velocity water can be created by
constructing the pipe outfall and associated energy dissipater back from the
stream edge and digging a channel, over -widened to the upstream side, from the
outfall. Overwintering juvenile and migrating adult salmonids may use the alcove
as shelter during high flows. Bank stabilization, bioengineering, and habitat
features may be required for disturbed areas. This work may require a HPA. See
Volume V (p.765) for more information on outfall system design.
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Maintenance Standards
• Inspect and repair as needed.
• Add rock as needed to maintain the intended function.
• Clean energy dissipater if sediment builds up.
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BMP C220: Storm Drain Inlet Protection
Purpose
Storm drain inlet protection prevents coarse sediment from entering drainage systems
prior to permanent stabilization of the disturbed area.
Conditions of Use
Use storm drain inlet protection at inlets that are operational before permanent
stabilization of the disturbed drainage area. Provide protection for all storm drain inlets
downslope and within 500 feet of a disturbed or construction area, unless conveying
runoff entering catch basins to a sediment pond or trap.
Also consider inlet protection for lawn and yard drains on new home construction.
These small and numerous drains coupled with lack of gutters in new home
construction can add significant amounts of sediment into the roof drain system. If
possible delay installing lawn and yard drains until just before landscaping or cap these
drains to pre- vent sediment from entering the system until completion of landscaping.
Provide 18- inches of sod around each finished lawn and yard drain.
Table II-4.2.2 Storm Drain Inlet Protection (p.358) lists several options for inlet
protection. All of the methods for storm drain inlet protection tend to plug and require a
high frequency of maintenance. Limit drainage areas to one acre or less. Possibly
provide emergency overflows with additional end -of -pipe treatment where stormwater
ponding would cause a hazard.
Design and Installation Specifications
Excavated Drop Inlet Protection - An excavated impoundment around the storm drain.
Sediment settles out of the stormwater prior to entering the storm drain.
• Provide a depth of 1-2 ft as measured from the crest of the inlet structure.
• Slope sides of excavation no steeper than 2H:1 V.
■ Minimum volume of excavation 35 cubic yard.
• Shape basin to fit site with longest dimension oriented toward the longest inflow
area.
• Install provisions for draining to prevent standing water problems.
• Clear the area of all debris.
■ Grade the approach to the inlet uniformly.
■ Drill weep holes into the side of the inlet.
• Protect weep holes with screen wire and washed aggregate.
• Seal weep holes when removing structure and stabilizing area.
■ Build a temporary dike, if necessary, to the down slope side of the structure to
prevent bypass flow.
Block and Gravel Filter - A barrier formed around the storm drain inlet with standard
concrete blocks and gravel. See Figure II-4.2.8 Block and Gravel Filter (p.360).
• Provide a height of 1 to 2 feet above inlet.
• Recess the first row 2-inches into the ground for stability.
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• Support subsequent courses by placing a 2x4 through the block opening.
• Do not use mortar.
• Lay some blocks in the bottom row on their side for dewatering the pool.
• Place hardware cloth or comparable wire mesh with 1/2-inch openings over all
• Block openings.
• Place gravel just below the top of blocks on slopes of 2H:1 V or flatter.
• An alternative design is a gravel donut.
• Provide an inlet slope of 3H:1 V.
■ Provide an outlet slope of 2H:1V.
■ Provide al -foot wide level stone area between the structure and the inlet.
• Use inlet slope stones 3 inches in diameter or larger.
• Use gravel '/2- to %-inch at a minimum thickness of 1-foot for the outlet slope.
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Gravel and Wire Mesh Filter - A gravel barrier placed over the top of the inlet. This
structure does not provide an overflow.
• Use a hardware cloth or comparable wire mesh with'/2-inch openings.
• Use coarse aggregate.
• Provide a height 1-foot or more, 18-inches wider than inlet on all sides.
• Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot
beyond each side of the inlet structure.
• Overlap the strips if more than one strip of mesh is necessary.
• Place coarse aggregate over the wire mesh.
• Provide at least a 12-inch depth of gravel over the entire inlet opening and
extend at least 18-inches on all sides.
Catchbasin Filters — Use inserts designed by manufacturers for construction sites. The
limited sediment storage capacity increases the amount of inspection and maintenance
required, which may be daily for heavy sediment loads. To reduce maintenance
requirements combine a catchbasin filter with another type of inlet protection. This type
of inlet protection provides flow bypass without overflow and therefore may be a better
method for inlets located along active rights -of -way.
• Provides 5 cubic feet of storage.
■ Requires dewatering provisions.
■ Provides a high -flow bypass that will not clog under normal use at a construction
site.
Insert the catchbasin filter in the catchbasin just below the grating.
Curb Inlet Protection with Wooden Weir— Barrier formed around a curb inlet with a
wooden frame and gravel.
■ Use wire mesh with '/2-inch openings.
• Use extra strength filter cloth.
■ Construct a frame.
• Attach the wire and filter fabric to the frame.
■ Pile coarse washed aggregate against wire/fabric.
• Place weight on frame anchors.
Block and Gravel Curb Inlet Protection — Barrier formed around a curb inlet with
concrete blocks and gravel. See Figure II-4.2.9 Block and Gravel Curb Inlet Protection
(p.363).
■ Use wire mesh with 1/2-inch openings.
• Place two concrete blocks on their sides abutting the curb at either side of the
inlet opening. These are spacer blocks.
• Place a 2x4 stud through the outer holes of each spacer block to align the front
blocks.
• Place blocks on their sides across the front of the inlet and abutting the spacer
blocks.
• Place wire mesh over the outside vertical face
• Pile coarse aggregate against the wire to the top of the barrier.
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Curb and Gutter Sediment Barrier— Sandbag or rock berm (riprap and aggregate) 3 feet
high and 3 feet wide in a horseshoe shape. See Figure II-4.2.10 Curb and Gutter Barrier
(p.364).
• Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap,
3 feet high and 3 feet wide, at least 2 feet from the inlet.
• Construct a horseshoe shaped sedimentation trap on the outside of the berm
sized to sediment trap standards for protecting a culvert inlet.
Maintenance Standards
• Inspect catch basin filters frequently, especially after storm events. Clean and
replace clogged inserts. For systems with clogged stone filters: pull away the
stones from the inlet and clean or replace. An alternative approach would be to
use the clogged stone as fill and put fresh stone around the inlet.
• Do not wash sediment into storm drains while cleaning. Spread all excavated
material evenly over the surrounding land area or stockpile and stabilize as
appropriate.
Approved as Equivalent
Ecology has approved products as able to meet the requirements of BMP C220: Storm
Drain Inlet Protection. The products did not pass through the Technology Assessment
Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to accept this
product approved as equivalent, or may require additional testing prior to consideration
for local use. The products are available for review on Ecology's website at
http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.htmI
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BMP C233: Silt Fence
Purpose
Use of a silt fence reduces the transport of coarse sediment from a construction site by
providing a temporary physical barrier to sediment and reducing the runoff velocities of
overland flow. See Figure II-4.2.12 Silt Fence (p.369) for details on silt fence
construction.
Conditions of Use
Silt fence may be used downslope of all disturbed areas.
■ Silt fence shall prevent soil carried by runoff water from going beneath, through,
or over the top of the silt fence, but shall allow the water to pass through the
fence.
■ Silt fence is not intended to treat concentrated flows, nor is it intended to treat
substantial amounts of overland flow. Convey any concentrated flows through the
drainage system to a sediment pond
• Do not construct silt fences in streams or use in V-shaped ditches. Silt fences do
not provide an adequate method of silt control for anything deeper than sheet or
overland flow.
Design and Installation Specifications
Use in combination with sediment basins or other BMPs.
• Maximum slope steepness (normal (perpendicular) to fence line) 1 H:1 V.
• Maximum sheet or overland flow path length to the fence of 100 feet.
• Do not allow flows greater than 0.5 cfs.
■ The geotextile used shall meet the following standards. All geotextile properties
listed below are minimum average roll values (i.e., the test result for any sampled
roll in a lot shall meet or exceed the values shown in Table II-4.2.3 Geotextile
Standards (p.370).
• Support standard strength fabrics with wire mesh, chicken wire, 2-inch x 2-inch
wire, safety fence, or jute mesh to increase the strength of the fabric. Silt fence
materials are available that have synthetic mesh backing attached.
• Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to
provide a minimum of six months of expected usable construction life at a
temperature range of 0°F. to 120°F.
■ One -hundred percent biodegradable silt fence is available that is strong, long
lasting, and can be left in place after the project is completed, if permitted by
local regulations.
■ Refer to Figure II-4.2.12 Silt Fence (p.369) for standard silt fence details. Include
the following standard Notes for silt fence on construction plans and
specifications:
1. The contractor shall install and maintain temporary silt fences at the locations
shown in the Plans.
2. Construct silt fences in areas of clearing, grading, or drainage prior to starting
those activities.
3. The silt fence shall have a 2-feet min. and a 2'/2-feet maximum height above
the original ground surface.
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4. The filter fabric shall be sewn together at the point of manufacture to form
filter fabric lengths as required. Locate all sewn seams at support posts.
Alternatively, two sections of silt fence can be overlapped, provided the
Contractor can demonstrate, to the satisfaction of the Engineer, that the
overlap is long enough and that the adjacent fence sections are close enough
together to prevent silt laden water from escaping through the fence at the
overlap.
5. Attach the filter fabric on the up -slope side of the posts and secure with
staples, wire, or in accordance with the manufacturer's recommendations.
Attach the filter fabric to the posts in a manner that reduces the potential for
tearing
6. 6. Support the filter fabric with wire or plastic mesh, dependent on the
properties of the geotextile selected for use. If wire or plastic mesh is used,
fasten the mesh securely to the up -slope side of the posts with the filter fabric
up -slope of the mesh.
7. Mesh support, if used, shall consist of steel wire with a maximum mesh
spacing of 2-inches, or a prefabricated polymeric mesh. The strength of the
wire or polymeric mesh shall be equivalent to or greater than 180 lbs. grab
tensile strength. The polymeric mesh must be as resistant to the same level
of ultraviolet radiation as the filter fabric it supports.
8. Bury the bottom of the filter fabric 4-inches min. below the ground surface.
Backfill and tamp soil in place over the buried portion of the filter fabric, so
that no flow can pass beneath the fence and scouring cannot occur. When
wire or polymeric back-up support mesh is used, the wire or polymeric mesh
shall extend into the ground 3-inches min.
9. Drive or place the fence posts into the ground 18-inches min. A 12—inch min.
depth is allowed if topsoil or other soft subgrade soil is not present and 18-
inches cannot be reached. Increase fence post min. depths by 6 inches if the
fence is located on slopes of 3H:1 V or steeper and the slope is perpendicular
to the fence. If required post depths cannot be obtained, the posts shall be
adequately secured by bracing or guying to prevent overturning of the fence
due to sediment loading.
10. Use wood, steel or equivalent posts. The spacing of the support posts shall
be a maximum of 6-feet. Posts shall consist of either:
a. Wood with dimensions of 2-inches by 2-inches wide min. and a
3-feet min. length. Wood posts shall be free of defects such as
knots, splits, or gouges.
b. No. 6 steel rebar or larger.
c. ASTM A 120 steel pipe with a minimum diameter of 1-inch.
d. U, T, L, or C shape steel posts with a minimum weight of 1.35
lbs./ft.
e. Other steel posts having equivalent strength and bending
resistance to the post sizes listed above.
11. Locate silt fences on contour as much as possible, except at the ends of the
fence, where the fence shall be turned uphill such that the silt fence captures
the runoff water and prevents water from flowing around the end of the fence.
12. If the fence must cross contours, with the exception of the ends of the fence,
place gravel check dams perpendicular to the back of the fence to minimize
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concentrated flow and erosion. The slope of the fence line where contours
must be crossed shall not be steeper than 3H:1 V.
a. Gravel check dams shall be approximately 1-foot deep at the back of the
fence. Gravel check dams shall be continued perpendicular to the fence at
the same elevation until the top of the check dam intercepts the ground
surface behind the fence.
b. Gravel check dams shall consist of crushed surfacing base course, gravel
backfill for walls, or shoulder ballast. Gravel check dams shall be located
every 10 feet along the fence where the fence must cross contours.
Refer to Figure II-4.2.13 Silt Fence Installation by Slicing Method (p.374) for
slicing method details. Silt fence installation using the slicing method
specifications:
o The base of both end posts must be at least 2- to 4-inches above the top
of the filter fabric on the middle posts for ditch checks to drain properly.
Use a hand level or string level, if necessary, to mark base points before
installation.
o Install posts 3- to 4-feet apart in critical retention areas and 6- to 7-feet
apart in standard applications.
o Install posts 24-inches deep on the downstream side of the silt fence, and
as close as possible to the filter fabric, enabling posts to support the filter
fabric from upstream water pressure.
o Install posts with the nipples facing away from the filter fabric.
o Attach the filter fabric to each post with three ties, all spaced within the top
8-inches of the filter fabric. Attach each tie diagonally 45 degrees through
the filter fabric, with each puncture at least 1-inch vertically apart. Each tie
should be positioned to hang on a post nipple when tightening to prevent
sagging.
o Wrap approximately 6-inches of fabric around the end posts and secure
with 3 ties.
o No more than 24-inches of a 36-inch filter fabric is allowed above ground
level.
o Compact the soil immediately next to the filter fabric with the front wheel of
the tractor, skid steer, or roller exerting at least 60 pounds per square
inch.
o Compact the upstream side first and then each side twice for a total of four
trips. Check and correct the silt fence installation for any deviation before
compaction. Use a flat -bladed shovel to tuck fabric deeper into the ground
if necessary.
P a g e 172 17764-SWPPP.docx
Insert Figure II-4.2.12
P a g e 173 17764-SWPPP.docx
BMP C240: Sediment Trap
Purpose
A sediment trap is a small temporary ponding area with a gravel outlet used to collect
and store sediment from sites cleared and/or graded during construction. Sediment
traps, along with other perimeter controls, shall be installed before any land disturbance
takes place in the drainage area.
Conditions of Use
Prior to leaving a construction site, stormwater runoff must pass through a sediment
pond or trap or other appropriate sediment removal best management practice.
Nonengineered sediment traps may be used on -site prior to an engineered sediment
trap or sediment pond to provide additional sediment removal capacity.
It is intended for use on sites where the tributary drainage area is less than 3 acres, with
no unusual drainage features, and a projected build -out time of six months or less. The
sediment trap is a temporary measure (with a design life of approximately 6 months)
and shall be maintained until the site area is permanently protected against erosion by
vegetation and/or structures.
Sediment traps and ponds are only effective in removing sediment down to about the
medium silt size fraction. Runoff with sediment of finer grades (fine silt and clay) will
pass through untreated, emphasizing the need to control erosion to the maximum extent
first.
Whenever possible, sediment -laden water shall be discharged into on -site, relatively
level, vegetated areas (see BMP C234: Vegetated Strip (p.375)). This is the only way to
effectively remove fine particles from runoff unless chemical treatment or filtration is
used. This can be particularly useful after initial treatment in a sediment trap or pond.
The areas of release must be evaluated on a site -by -site basis in order to determine
appropriate locations for and methods of releasing runoff. Vegetated wetlands shall not
be used for this purpose. Frequently, it may be possible to pump water from the
collection point at the downhill end of the site to an upslope vegetated area. Pumping
shall only augment the treatment system, not replace it, because of the possibility of
pump failure or runoff volume in excess of pump capacity.
All projects that are constructing permanent facilities for runoff quantity control should
use the rough -graded or final -graded permanent facilities for traps and ponds. This
includes combined facilities and infiltration facilities. When permanent facilities are used
as temporary sedimentation facilities, the surface area requirement of a sediment trap
or pond must be met. If the surface area requirements are larger than the surface area
of the permanent facility, then the trap or pond shall be enlarged to comply with the
surface area requirement. The permanent pond shall also be divided into two cells as
required for sediment ponds.
Either a permanent control structure or the temporary control structure (described in
BMPC241: Temporary Sediment Pond (p.388)) can be used. If a permanent control
structure is used, it may be advisable to partially restrict the lower orifice with gravel to
P a g e 174 17764-SWPPP.docx
increase residence time while still allowing dewatering of the pond. A shut-off valve may
be added to the control structure to allow complete retention of stormwater in
emergency situations. In this case, an emergency overflow weir must be added.
A skimmer may be used for the sediment trap outlet if approved by the Local Permitting
Authority.
Design and Installation Specifications
See Figure II-4.2.16 Cross Section of Sediment Trap (p.386) and Figure II-4.2.17
Sediment Trap Outlet (p.387) for details.
• If permanent runoff control facilities are part of the project, they should be used
for sediment retention.
• To determine the sediment trap geometry, first calculate the design surface area
(SA) of the trap, measured at the invert of the weir. Use the following equation:
SA = FS(Q2/Vs)
Where,
Q2 = Design inflow based on the peak discharge from the developed 2-year runoff
event from the contributing drainage area as computed in the hydrologic analysis. The
10-year peak flow shall be used if the project size, expected timing and duration of
construction, or downstream conditions warrant a higher level of protection. If no
hydrologic analysis is required, the Rational Method may be used.
Vs = The settling velocity of the soil particle of interest. The 0.02 mm (medium silt)
particle with an assumed density of 2.65 g/cm3 has been selected as the particle of
interest and has a settling velocity (Vs) of 0.00096 ft/sec.
FS = A safety factor of 2 to account for non -ideal settling.
Therefore, the equation for computing surface area becomes:
SA = 2 x Q2/0.00096
or
2080 square feet per cfs of inflow.
Note: Even if permanent facilities are used, they must still have a surface area that is at
least as large as that derived from the above formula. If they do not, the pond must be
enlarged.
To aid in determining sediment depth, all sediment traps shall have a staff gauge
with a prominent mark 1-foot above the bottom of the trap.
Sediment traps may not be feasible on utility projects due to the limited work
space or the short-term nature of the work. Portable tanks may be used in place
of sediment traps for utility projects.
Maintenance Standards
• Sediment shall be removed from the trap when it reaches 1-foot in depth.
• Any damage to the pond embankments or slopes shall be repaired.
P a g e 175 17764-SWPPP.docx
BMP C103: High Visibility Fence
Purpose
Fencing is intended to:
1. Restrict clearing to approved limits.
2. Prevent disturbance of sensitive areas, their buffers, and other areas
required to be left undisturbed.
3. Limit construction traffic to designated construction entrances, exits,
or internal roads.
4. Protect areas where marking with survey tape may not provide
adequate protection.
Conditions of Use
To establish clearing limits plastic, fabric, or metal fence may be used:
• At the boundary of sensitive areas, their buffers, and other areas
required to be left uncleared.
• As necessary to control vehicle access to and on the site.
Design and
High visibility plastic fence shall be composed of a high -density
Installation
polyethylene material and shall be at least four feet in height. Posts for
Specifications
the fencing shall be steel or wood and placed every 6 feet on center
(maximum) or as needed to ensure rigidity. The fencing shall be fastened
to the post every six inches with a polyethylene tie. On long continuous
lengths of fencing, a tension wire or rope shall be used as a top stringer to
prevent sagging between posts. The fence color shall be high visibility
orange. The fence tensile strength shall be 360 lbs./ft. using the ASTM
D4595 testing method.
If appropriate install fabric silt fence in accordance with BMP C233 to
act as high visibility fence. Silt fence shall be at least 3 feet high and
must be highly visible to meet the requirements of this BMP.
Metal fences shall be designed and installed according to the
manufacturer's specifications.
Metal fences shall be at least 3 feet high and must be highly visible.
Fences shall not be wired or stapled to trees.
Maintenance If the fence has been damaged or visibility reduced, it shall be repaired or
Standards replaced immediately and visibility restored.
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BMP C105: Stabilized Construction Entrance / Exit
Purpose Stabilized Construction entrances are established to reduce the amount of
sediment transported onto paved roads by vehicles or equipment. This is
done by constructing a stabilized pad of quarry spalls at entrances and
exits for construction sites.
Conditions of Use Construction entrances shall be stabilized wherever traffic will be entering
or leaving a construction site if paved roads or other paved areas are
within 1,000 feet of the site.
For residential construction provide stabilized construction entrances for
each residence, rather than only at the main subdivision entrance.
Stabilized surfaces shall be of sufficient length/width to provide vehicle
access/parking, based on lot size/configuration.
On large commercial, highway, and road projects, the designer should
include enough extra materials in the contract to allow for additional
stabilized entrances not shown in the initial Construction SWPPP. It is
difficult to determine exactly where access to these projects will take
place; additional materials will enable the contractor to install them where
needed.
Design and See Figure 4.1.1 for details. Note: the 100' minimum length of the
Installation entrance shall be reduced to the maximum practicable size when the size
Specifications or configuration of the site does not allow the full length (100').
Construct stabilized construction entrances with a 12-inch thick pad of 4-
inch to 8-inch quarry spalls, a 4-inch course of asphalt treated base
(ATB), or use existing pavement. Do not use crushed concrete, cement,
or calcium chloride for construction entrance stabilization because these
products raise pH levels in stormwater and concrete discharge to surface
waters of the State is prohibited.
A separation geotextile shall be placed under the spalls to prevent fine
sediment from pumping up into the rock pad. The geotextile shall meet
the following standards:
Grab Tensile Strength (ASTM D4751)
200 psi min.
Grab Tensile Elongation (ASTM
30% max.
D4632)
Mullen Burst Strength (ASTM
400 psi min.
D3786-80a)
AOS (ASTM D4751)
20-45 (U.S. standard sieve
size)
■ Consider early installation of the first lift of asphalt in areas that will
paved; this can be used as a stabilized entrance. Also consider the
installation of excess concrete as a stabilized entrance. During large
concrete pours, excess concrete is often available for this purpose.
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-7
■ Fencing (see BMP C 1 Q3} shall be installed as necessary to restrict
traffic to the construction entrance.
■ Whenever possible, the entrance shall be constructed on a firm,
compacted subgrade. This can substantially increase the effectiveness
of the pad and reduce the need for maintenance.
Construction entrances should avoid crossing existing sidewalks and
back of walk drains if at all possible. If a construction entrance must
cross a sidewalk or back of walk drain, the full length of the sidewalk
and back of walk drain must be covered and protected from sediment
leaving the site.
Maintenance Quarry spalls shall be added if the pad is no longer in accordance with
Standards the specifications.
If the entrance is not preventing sediment from being tracked onto
pavement, then alternative measures to keep the streets free of
sediment shall be used. This may include replacement/cleaning of the
existing quarry spalls, street sweeping, an increase in the dimensions
of the entrance, or the installation of a wheel wash.
Any sediment that is tracked onto pavement shall be removed by
shoveling or street sweeping. The sediment collected by sweeping
shall be removed or stabilized on site. The pavement shall not be
cleaned by washing down the street, except when high efficiency
sweeping is ineffective and there is a threat to public safety. If it is
necessary to wash the streets, the construction of a small sump to
contain the wash water shall be considered. The sediment would then
be washed into the sump where it can be controlled.
• Perform street sweeping by hand or with a high efficiency sweeper. Do
not use a non -high efficiency mechanical sweeper because this creates
dust and throws soils into storm systems or conveyance ditches.
• Any quarry spalls that are loosened from the pad, which end up on the
roadway shall be removed immediately.
• If vehicles are entering or exiting the site at points other than the
construction entrance(s), fencing (see BMP C103) shall be installed to
control traffic.
■ Upon project completion and site stabilization, all construction
accesses intended as permanent access for maintenance shall be
permanently stabilized.
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-8
Install driveway culvert if there
is a roadside ditch present
Driveway shall meet the
requirements of the
permitting agency
It is recommended that the
entrance be crowned so that
runoff drains off the pad
Provide full width of
ingress/eqress area
Figure 4.1.1 — Stabilized Construction Entrance
Approved as Ecology has approved products as able to meet the requirements of BMP
Equivalent C 105. The products did not pass through the Technology Assessment
Protocol — Ecology (TAPE) process. Local jurisdictions may choose not
to accept this product approved as equivalent, or may require additional
testing prior to consideration for local use. The products are available for
review on Ecology's website at
http:llwww.ea.wa.gov/programs/wq/stormwater/newtech/equ ivalent. htm 1
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-9
BMP C107: Construction Road/Parking Area Stabilization
Purpose Stabilizing subdivision roads, parking areas, and other on -site vehicle
transportation routes immediately after grading reduces erosion caused by
construction traffic or runoff.
Conditions of Use Roads or parking areas shall be stabilized wherever they are constructed,
whether permanent or temporary, for use by construction traffic.
• High Visibility Fencing (see BMP C103) shall be installed, if
necessary, to limit the access of vehicles to only those roads and
parking areas that are stabilized.
Design and On areas that will receive asphalt as part of the project, install the first
Installation lift as soon as possible.
Specifications A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed
• surfacing base course shall be applied immediately after grading or
utility installation. A 4-inch course of asphalt treated base (ATB) may
also be used, or the road/parking area may be paved. It may also be
possible to use cement or calcium chloride for soil stabilization. If
cement or cement kiln dust is used for roadbase stabilization, pH
monitoring and BMPs (BMPs C252 and C253) are necessary to
evaluate and minimize the effects on stormwater. If the area will not be
used for permanent roads, parking areas, or structures, a 6-inch depth of
hog fuel may also be used, but this is likely to require more
maintenance. Whenever possible, construction roads and parking areas
shall be placed on a firm, compacted subgrade.
• Temporary road gradients shall not exceed 15 percent. Roadways shall
be carefully graded to drain. Drainage ditches shall be provided on
each side of the roadway in the case of a crowned section, or on one
side in the case of a super -elevated section. Drainage ditches shall be
directed to a sediment control BMP.
Rather than relying on ditches, it may also be possible to grade the
road so that runoff sheet -flows into a heavily vegetated area with a
well -developed topsoil. Landscaped areas are not adequate. If this area
has at least 50 feet of vegetation that water can flow through, then it is
generally preferable to use the vegetation to treat runoff, rather than a
sediment pond or trap. The 50 feet shall not include wetlands or their
buffers. If runoff is allowed to sheetflow through adjacent vegetated
areas, it is vital to design the roadways and parking areas so that no
concentrated runoff is created.
• Storm drain inlets shall be protected to prevent sediment -laden water
entering the storm drain system (see BMP C220).
Maintenance Inspect stabilized areas regularly, especially after large storm events.
Standards Crushed rock, gravel base, etc. shall be added as required to maintain a
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-12
stable driving surface and to stabilize any areas that have eroded.
Following construction, these areas shall be restored to pre -construction
condition or better to prevent future erosion.
Perform street cleaning at the end of each day or more often if necessary.
BMP C120: Temporary and Permanent Seeding
Purpose Seeding reduces erosion by stabilizing exposed soils. A well -established
vegetative cover is one of the most effective methods of reducing erosion.
Conditions of Use Use seeding throughout the project on disturbed areas that have reached
final grade or that will remain unworked for more than 30 days.
The optimum seeding windows for western Washington are April 1
through June 30 and September 1 through October 1.
Between July 1 and August 30 seeding requires irrigation until 75 percent
grass cover is established.
Between October 1 and March 30 seeding requires a cover of mulch with
straw or an erosion control blanket until 75 percent grass cover is
established.
Review all disturbed areas in late August to early September and complete
all seeding by the end of September. Otherwise, vegetation will not
establish itself enough to provide more than average protection.
Mulch is required at all times for seeding because it protects seeds
from heat, moisture loss, and transport due to runoff. Mulch can be
applied on top of the seed or simultaneously by hydroseeding. See
BMP C121: Mulching for specifications.
Seed and mulch, all disturbed areas not otherwise vegetated at final
site stabilization. Final stabilization means the completion of all soil
disturbing activities at the site and the establishment of a permanent
vegetative cover, or equivalent permanent stabilization measures (such
as pavement, riprap, gabions or geotextiles) which will prevent
erosion.
Design and Seed retention/detention ponds as required.
Installation Install channels intended for vegetation before starting major
Specifications earthwork and hydroseed with a Bonded Fiber Matrix. For vegetated
channels that will have high flows, install erosion control blankets
over hydroseed. Before allowing water to flow in vegetated
channels, establish 75 percent vegetation cover. If vegetated
channels cannot be established by seed before water flow; install sod
in the channel bottom —mover hydromulch and erosion control
blankets.
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4-13
Generally, products come in 40-50 pound bags and include all
necessary ingredients except for seed and fertilizer.
• BFMs and MBFMs provide good alternatives to blankets in most
areas requiring vegetation establishment. Advantages over
blankets include:
• BFM and MBFMs do not require surface preparation.
• Helicopters can assist in installing BFM and MBFMs in remote
areas.
• On slopes steeper than 2.5H:IV, blanket installers may require
ropes and harnesses for safety.
• Installing BFM and MBFMs can save at least $1,000 per acre
compared to blankets.
Maintenance Reseed any seeded areas that fail to establish at least 80 percent cover
Standards (100 percent cover for areas that receive sheet or concentrated flows). If
reseeding is ineffective, use an alternate method such as sodding,
mulching, or nets/blankets. If winter weather prevents adequate grass
growth, this time limit may be relaxed at the discretion of the local
authority when sensitive areas would otherwise be protected.
• Reseed and protect by mulch any areas that experience erosion after
achieving adequate cover. Reseed and protect by mulch any eroded
area.
• Supply seeded areas with adequate moisture, but do not water to the
extent that it causes runoff.
Approved as Ecology has approved products as able to meet the requirements of BMP
Equivalent C 120. The products did not pass through the Technology Assessment
Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to
accept this product approved as equivalent, or may require additional testing
prior to consideration for local use. The products are available for review on
Ecology's website at
htIR://www.ecy.wa.goy/
program s/wg/storm water/n e_wtech/egu i va l ent. h tml
BMP C121: Mulching
Purpose Mulching soils provides immediate temporary protection from erosion.
Mulch also enhances plant establishment by conserving moisture, holding
fertilizer, seed, and topsoil in place, and moderating soil temperatures.
There is an enormous variety of mulches that can be used. This section
discusses only the most common types of mulch.
Conditions of Use As a temporary cover measure, mulch should be used:
■ For less than 30 days on disturbed areas that require cover.
• At all times for seeded areas, especially during the wet season and
Volume II — Construction Stormwater Pollution Prevention -August 2012
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during the hot summer months.
• During the wet season on slopes steeper than 3H:1V with more than
10 feet of vertical relief.
Mulch may be applied at any time of the year and must be refreshed
periodically.
For seeded areas mulch may be made up of 100 percent: cottonseed
meal; fibers made of wood, recycled cellulose, hemp, kenaf; compost;
or blends of these. Tackifier shall be plant -based, such as guar or alpha
plantago, or chemical -based such as polyacrylamide or polymers. Any
mulch or tackifier product used shall be installed per manufacturer's
instructions. Generally, mulches come in 40-50 pound bags. Seed and
fertilizer are added at time of application.
Design and For mulch materials, application rates, and specifications, see Table 4.1.8.
Installation Always use a 2-inch minimum mulch thickness; increase the thickness
Specifications until the ground is 95% covered (i.e. not visible under the mulch layer).
Note: Thickness may be increased for disturbed areas in or near sensitive
areas or other areas highly susceptible to erosion.
Mulch used within the ordinary high-water mark of surface waters should
be selected to minimize potential flotation of organic matter. Composted
organic materials have higher specific gravities (densities) than straw,
wood, or chipped material. Consult Hydraulic Permit Authority (HPA) for
mulch mixes if applicable.
Maintenance ■ The thickness of the cover must be maintained.
Standards • Any areas that experience erosion shall be remulched and/or protected
with a net or blanket. If the erosion problem is drainage related, then
the problem shall be fixed and the eroded area remulched.
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-20
Table 4.1.8
Mulch Standards and Guidelines
Application
Mulch Material
Quality Standards
Rates
Remarks
Straw
Air-dried; free from
2"-3" thick; 5
Cost-effective protection when applied with adequate thickness.
undesirable seed and
bales per 1,000
Hand -application generally requires greater thickness than
coarse material.
sf or 2-3 tons per
blown straw. The thickness of straw may be reduced by half
acre
when used in conjunction with seeding. In windy areas straw
must be held in place by crimping, using a tackifier, or covering
with netting. Blown straw always has to be held in place with a
tackifier as even light winds will blow it away. Straw, however,
has several deficiencies that should be considered when
selecting mulch materials. It often introduces and/or encourages
the propagation of weed species and it has no significant long-
term benefits. It should also not be used within the ordinary
high-water elevation of surface waters (due to flotation).
Hydromulch
No growth
Approx. 25-30
Shall be applied with hydromulcher. Shall not be used without
inhibiting factors.
lbs per 1,000 sf
seed and tackifier unless the application rate is at least doubled.
or 1,500 - 2,000
Fibers longer than about 3/a-1 inch clog hydromulch equipment.
lbs per acre
Fibers should be kept to less than '/< inch.
Composted
No visible water or
2" thick min.;
More effective control can be obtained by increasing thickness
Mulch and
dust during
approx. 100 tons
to 3". Excellent mulch for protecting final grades until
Compost
handling. Must be
per acre (approx.
landscaping because it can be directly seeded or tilled into soil
produced in
800 lbs per yard)
as an amendment. Composted mulch has a coarser size
accordance with
gradation than compost. It is more stable and practical to use in
WAC 173-350,
wet areas and during rainy weather conditions. Do not use
Solid Waste
composted mulch near wetlands or near phosphorous impaired
Handling Standards.
water bodies.
Chipped Site
Average size shall
2" thick min.;
This is a cost-effective way to dispose of debris from clearing
Vegetation
be several inches.
and grubbing, and it eliminates the problems associated with
Gradations from
burning. Generally, it should not be used on slopes above
fines to 6 inches in
approx. 10% because of its tendency to be transported by
length for texture,
runoff. It is not recommended within 200 feet of surface waters.
variation, and
If seeding is expected shortly after mulch, the decomposition of
interlocking
the chipped vegetation may tie up nutrients important to grass
properties.
establishment.
Wood -based
No visible water or
2" thick min.;
This material is often called "hog or hogged fuel." The use of
Mulch or Wood
dust during
approx. 100 tons
mulch ultimately improves the organic matter in the soil.
Straw
handling. Must be
per acre (approx.
Special caution is advised regarding the source and composition
purchased from a
800 lbs. per
of wood -based mulches. Its preparation typically does not
supplier with a Solid
cubic yard)
provide any weed seed control, so evidence of residual
Waste Handling
vegetation in its composition or known inclusion of weed plants
Permit or one
or seeds should be monitored and prevented (or minimized).
exempt from solid
waste regulations.
Wood Strand
A blend of loose,
2" thick min.
Cost-effective protection when applied with adequate thickness.
Mulch
long, thin wood
A minimum of 95-percent of the wood strand shall have lengths
pieces derived from
between 2 and 10-inches, with a width and thickness between
native conifer or
1/16 and %-inches. The mulch shall not contain resin, tannin, or
deciduous trees with
other compounds in quantities that would be detrimental to plant
high length -to -width
life. Sawdust or wood shavings shall not be used as mulch.
ratio.
(WSDOT specification (9-14.4(4))
Volume II — Construction Stormwater Pollution Prevention - August 2012
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BMP C123: Plastic Covering
Purpose Plastic covering provides immediate, short-term erosion protection to
slopes and disturbed areas.
Conditions of Plastic covering may be used on disturbed areas that require cover
Use measures for less than 30 days, except as stated below.
• Plastic is particularly useful for protecting cut and fill slopes and
stockpiles. Note: The relatively rapid breakdown of most polyethylene
sheeting makes it unsuitable for long-term (greater than six months)
applications.
+ Due to rapid runoff caused by plastic covering, do not use this method
upslope of areas that might be adversely impacted by concentrated
runoff. Such areas include steep and/or unstable slopes.
• Plastic sheeting may result in increased runoff volumes and velocities,
requiring additional on -site measures to counteract the increases.
Creating a trough with wattles or other material can convey clean
water away from these areas.
■ To prevent undercutting, trench and backfill rolled plastic covering
products.
• While plastic is inexpensive to purchase, the added cost of
installation, maintenance, removal, and disposal make this an
expensive material, up to $1.50-2.00 per square yard.
Whenever plastic is used to protect slopes install water collection
measures at the base of the slope. These measures include plastic -
covered berms, channels, and pipes used to covey clean rainwater
away from bare soil and disturbed areas. Do not mix clean runoff from
a plastic covered slope with dirty runoff from a project.
■ Other uses for plastic include:
1. Temporary ditch liner.
2. Pond liner in temporary sediment pond.
3. Liner for bermed temporary fuel storage area if plastic is not
reactive to the type of fuel being stored.
4. Emergency slope protection during heavy rains.
5. Temporary drainpipe ("elephant trunk") used to direct water.
Design and Plastic slope cover must be installed as follows:
Installation 1. Run plastic up and down slope, not across slope.
Specifications
2. Plastic may be installed perpendicular to a slope if the slope length
is less than 10 feet.
3. Minimum of 8-inch overlap at seams.
Volume II— Construction Stormwater Pollution Prevention - August 2012
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4. On long or wide slopes, or slopes subject to wind, tape all seams.
5. Place plastic into a small (I2-inchwide by 6-inch deep) slot trench
at the top of the slope and backfill with soil to keep water from
flowing underneath.
6. Place sand filled burlap or geotextile bags every 3 to 6 feet along
seams and tie them together with twine to hold them in place.
7. Inspect plastic for rips, tears, and open seams regularly and repair
immediately. This prevents high velocity runoff from contacting
bare soil which causes extreme erosion.
8. Sandbags may be lowered into place tied to ropes. However, all
sandbags must be staked in place.
Plastic sheeting shall have a minimum thickness of 0.06 millimeters.
If erosion at the toe of a slope is likely, a gravel berm, riprap, or other
suitable protection shall be installed at the toe of the slope in order to
reduce the velocity of runoff.
Maintenance + Torn sheets must be replaced and open seams repaired.
Standards • Completely remove and replace the plastic if it begins to deteriorate
due to ultraviolet radiation.
• Completely remove plastic when no longer needed.
Dispose of old tires used to weight down plastic sheeting
appropriately.
Approved as Ecology has approved products as able to meet the requirements of BMP
Equivalent C123. The products did not pass through the Technology Assessment
Protocol — Ecology (TAPE) process. Local jurisdictions may choose not
to accept this product approved as equivalent, or may require additional
testing prior to consideration for local use. The products are available for
review on Ecology's website at
http: //www. ecy. wa. govlprograms/wg/stormwater/n ewte ch/equ iva l e nt. ht m l
Volume II— Construction Stormwater Pollution Prevention - August 2012
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BMP C125: Topsoiling / Composting
Purpose Topsoiling and composting provide a suitable growth medium for final
site stabilization with vegetation. While not a permanent cover practice in
itself, topsoiling and composting are an integral component of providing
permanent cover in those areas where there is an unsuitable soil surface
for plant growth. Use this BMP in conjunction with other BMPs such as
seeding, mulching, or sodding.
Native soils and disturbed soils that have been organically amended not
only retain much more stormwater, but they also serve as effective
biofilters for urban pollutants and, by supporting more vigorous plant
growth, reduce the water, fertilizer and pesticides needed to support
Volume II — Construction Stormwater Pollution Prevention -August 2012
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installed landscapes. Topsoil does not include any subsoils but only the
material from the top several inches including organic debris.
Conditions of ■ Permanent landscaped areas shall contain healthy topsoil that reduces
Use the need for fertilizers, improves overall topsoil quality, provides for
better vegetal health and vitality, improves hydrologic characteristics,
and reduces the need for irrigation.
• Leave native soils and the duff layer undisturbed to the maximum
extent practicable. Stripping of existing, properly functioning soil
system and vegetation for the purpose of topsoiling during
construction is not acceptable. Preserve existing soil systems in
undisturbed and uncompacted conditions if functioning properly.
■ Areas that already have good topsoil, such as undisturbed areas, do not
require soil amendments.
• Restore, to the maximum extent practical, native soils disturbed during
clearing and grading to a condition equal to or better than the original
site condition's moisture -holding capacity. Use on -site native topsoil,
incorporate amendments into on -site soil, or import blended topsoil to
meet this requirement.
■ Topsoiling is a required procedure when establishing vegetation on
shallow soils, and soils of critically low pH (high acid) levels.
• Beware of where the topsoil comes from, and what vegetation was on
site before disturbance, invasive plant seeds may be included and could
cause problems for establishing native plants, landscaped areas, or
grasses.
• Topsoil from the site will contain mycorrhizal bacteria that are
necessary for healthy root growth and nutrient transfer. These native
mycorrhiza are acclimated to the site and will provide optimum
conditions for establishing grasses. Use commercially available
mycorrhiza products when using off -site topsoil.
Design and Meet the following requirements for areas requiring disruption and
Installation topsoiling:
Specifications , Maximize the depth of the topsoil wherever possible to provide the
maximum possible infiltration capacity and beneficial growth
medium. Topsoil shall have:
A minimum depth of 8-inches. Scarify subsoils below the topsoil
layer at least 4-inches with some incorporation of the upper
material to avoid stratified layers, where feasible. Ripping or re-
structuring the subgrade may also provide additional benefits
regarding the overall infiltration and interflow dynamics of the soil
system.
Volume II— Construction Stormwater Pollution Prevention - August 2012
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A minimum organic content of 10% dry weight, and 5% organic
matter content in turf areas. Incorporate organic amendments to a
minimum 8-inch depth except where tree roots or other natural
features limit the depth of incorporation.
■ A pH between 6.0 and 8.0 or matching the pH of the undisturbed
soil.
• If blended topsoil is imported, then fines should be limited to 25
percent passing through a 200 sieve.
• Accomplish the required organic content and pH by either returning
native topsoil to the site and/or incorporating organic amendments.
■ To meet the organic content use compost that meets the definition
of "composted materials" in WAC 173-350-220. This code is
available online at:
http://al2ns.leg,wa.gov/WAC/default.asl2x?citc=1 73-350-220.
The compost must also have an organic matter content of 35% to
65%, and a carbon to nitrogen ratio below 25H:1V.
The carbon to nitrogen ratio may be as high as 35H:1 V for
plantings composed entirely of plants native to the Puget Sound
Lowlands region.
For till soils use a mixture of approximately two parts soil to one
part compost. This equates to 4 inches of compost mixed to a depth
of 12 inches in till soils. Increasing the concentration of compost
beyond this level can have negative effects on vegetal health, while
decreasing the concentrations can reduce the benefits of amended
soils.
• Gravel or cobble outwash soils, may require different approaches.
Organics and fines easily migrate through the loose structure of
these soils. Therefore, the importation of at least 6 inches of
quality topsoil, underlain by some type of filter fabric to prevent
the migration of fines, may be more appropriate for these soils.
The final composition and construction of the soil system will result in
a natural selection or favoring of certain plant species over time. For
example, incorporation of topsoil may favor grasses, while layering
with mildly acidic, high -carbon amendments may favor more woody
vegetation.
• Allow sufficient time in scheduling for topsoil spreading prior to
seeding, sodding, or planting.
• Take care when applying top soil to subsoils with contrasting textures.
Sandy topsoil over clayey subsoil is a particularly poor combination,
as water creeps along the junction between the soil layers and causes
the topsoil to slough. If topsoil and subsoil are not properly bonded,
water will not infiltrate the soil profile evenly and it will be difficult to
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-30
establish vegetation. The best method to prevent a lack of bonding is
to actually work the topsoil into the layer below for a depth of at least
6 inches.
• Field exploration of the site shall be made to determine if there is
surface soil of sufficient quantity and quality to justify stripping.
Topsoil shall be friable and loamy (loam, sandy loam, silt loam, sandy
clay loam, and clay loam). Avoid areas of natural ground water
recharge.
■ Stripping shall be confined to the immediate construction area. A 4-
inch to 6-inch stripping depth is common, but depth may vary
depending on the particular soil. All surface runoff control structures
shall be in place prior to stripping.
• Do not place topsoil while in a frozen or muddy condition, when the
subgrade is excessively wet, or when conditions exist that may
otherwise be detrimental to proper grading or proposed sodding or
seeding.
• In any areas requiring grading remove and stockpile the duff layer and
topsoil on site in a designated, controlled area, not adjacent to public
resources and critical areas. Stockpiled topsoil is to be reapplied to
other portions of the site where feasible.
• Locate the topsoil stockpile so that it meets specifications and does not
interfere with work on the site. It may be possible to locate more than
one pile in proximity to areas where topsoil will be used.
Stockpiling of topsoil shall occur in the following manner:
• Side slopes of the stockpile shall not exceed 2H:IV.
Between October 1 and April 30:
• An interceptor dike with gravel outlet and silt fence shall
surround all topsoil.
Within 2 days complete erosion control seeding, or covering
stockpiles with clear plastic, or other mulching materials.
Between May 1 and September 30:
• An interceptor dike with gravel outlet and silt fence shall
surround all topsoil if the stockpile will remain in place for a
longer period of time than active construction grading.
Within 7 days complete erosion control seeding, or covering
stockpiles with clear plastic, or other mulching materials.
• When native topsoil is to be stockpiled and reused the following
should apply to ensure that the mycorrhizal bacterial, earthworms, and
other beneficial organisms will not be destroyed:
1. Re -install topsoil within 4 to 6 weeks.
Volume H— Construction Stormwater Pollution Prevention - August 2012
4-31
2. Do not allow the saturation of topsoil with water.
3. Do not use plastic covering.
Maintenance • Inspect stockpiles regularly, especially after large storm events.
Standards Stabilize any areas that have eroded.
• Establish soil quality and depth toward the end of construction and
once established, protect from compaction, such as from large
machinery use, and from erosion.
• Plant and mulch soil after installation.
■ Leave plant debris or its equivalent on the soil surface to replenish
organic matter.
Reduce and adjust, where possible, the use of irrigation, fertilizers,
herbicides and pesticides, rather than continuing to implement
formerly established practices.
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BMP C140: Dust Control
Purpose
Dust control prevents wind transport of dust from disturbed soil surfaces
onto roadways, drainage ways, and surface waters.
Conditions of Use
• In areas (including roadways) subject to surface and air movement of
dust where on -site and off -site impacts to roadways, drainage ways, or
surface waters are likely.
Design and
• Vegetate or mulch areas that will not receive vehicle traffic. In areas
Installation
where planting, mulching, or paving is impractical, apply gravel or
Specifications
landscaping rock.
• Limit dust generation by clearing only those areas where immediate
activity will take place, leaving the remaining area(s) in the original
condition. Maintain the original ground cover as long as practical.
Construct natural or artificial windbreaks or windscreens. These may
be designed as enclosures for small dust sources.
• Sprinkle the site with water until surface is wet. Repeat as needed. To
prevent carryout of mud onto street, refer to Stabilized Construction
Entrance (BM P C 105).
Irrigation water can be used for dust control. Irrigation systems should
be installed as a first step on sites where dust control is a concern.
• Spray exposed soil areas with a dust palliative, following the
manufacturer's instructions and cautions regarding handling and
application. Used oil is prohibited from use as a dust suppressant.
Local governments may approve other dust palliatives such as calcium
chloride or PAM.
• PAM (BMP C 126) added to water at a rate of 0.5 lbs. per 1,000
gallons of water per acre and applied from a water truck is more
effective than water alone. This is due to increased infiltration of water
into the soil and reduced evaporation. In addition, small soil particles
are bonded together and are not as easily transported by wind. Adding
PAM may actually reduce the quantity of water needed for dust
control. Use of PAM could be a cost-effective dust control method.
Techniques that can be used for unpaved roads and lots include:
• Lower speed limits. High vehicle speed increases the amount of dust
stirred up from unpaved roads and lots.
• Upgrade the road surface strength by improving particle size, shape,
and mineral types that make up the surface and base materials.
Add surface gravel to reduce the source of dust emission. Limit the
amount of fine particles (those smaller than .075 mm) to 10 to 20
percent.
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-40
Design and
Installation
Specifications
Maintenance
Standards
Depending on project type, size, complexity, and length, materials and
quantities will vary. A good minimum list of items that will cover
numerous situations includes:
Material
Clear Plastic, 6 mil
Drainpipe, 6 or 8 inch diameter
Sandbags, filled
Straw Bales for mulching,
Quarry S alls
Washed Gravel
Geotextile Fabric
Catch Basin Inserts
Steel "T" Posts
Silt fence material
Straw Wattles
• All materials with the exception of the quarry spalls, steel "T" posts,
and gravel should be kept covered and out of both sun and rain.
• Re -stock materials used as needed.
BMP C151: Concrete Handling
Purpose Concrete work can generate process water and slurry that contain fine
particles and high pH, both of which can violate water quality standards in
the receiving water. Concrete spillage or concrete discharge to surface
waters of the State is prohibited. Use this BMP to minimize and eliminate
concrete, concrete process water, and concrete slurry from entering waters
of the state.
Conditions of Use Any time concrete is used, utilize these management practices. Concrete
construction projects include, but are not limited to, the following:
• Curbs
• Sidewalks
• Roads
• Bridges
• Foundations
• Floors
■ Runways
Design and • Wash out concrete truck chutes, pumps, and internals into formed
Installation areas only. Assure that washout of concrete trucks is performed off -
Volume II — Construction Stormwater Pollution Prevention - August 2012
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Specifications site or in designated concrete washout areas. Do not wash out concrete
trucks onto the ground, or into storm drains, open ditches, streets, or
streams. Refer to BMP C 154 for information on concrete washout
areas.
• Return unused concrete remaining in the truck and pump to the
originating batch plant for recycling. Do not dump excess concrete on
site, except in designated concrete washout areas.
• Wash off hand tools including, but not limited to, screeds, shovels,
rakes, floats, and trowels into formed areas only.
■ Wash equipment difficult to move, such as concrete pavers in areas
that do not directly drain to natural or constructed stormwater
conveyances.
• Do not allow washdown from areas, such as concrete aggregate
driveways, to drain directly to natural or constructed stormwater
conveyances.
• Contain washwater and leftover product in a lined container when no
formed areas are available,. Dispose of contained concrete in a manner
that does not violate ground water or surface water quality standards.
• Always use forms or solid barriers for concrete pours, such as pilings,
within 15-feet of surface waters.
• Refer to BMPs C252 and C253 for pH adjustment requirements.
• Refer to the Construction Stormwater General Permit for pH
monitoring requirements if the project involves one of the following
activities:
• Significant concrete work (greater than 1,000 cubic yards poured
concrete or recycled concrete used over the life of a project).
• The use of engineered soils amended with (but not limited to)
Portland cement -treated base, cement kiln dust or fly ash.
■ Discharging stormwater to segments of water bodies on the 303(d)
list (Category 5) for high pH.
Maintenance Check containers for holes in the liner daily during concrete pours and
Standards repair the same day.
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-43
BMP C154: Concrete Washout Area
Purpose Prevent or reduce the discharge of pollutants to stormwater from concrete
waste by conducting washout off -site, or performing on -site washout in a
designated area to prevent pollutants from entering surface waters or
ground water.
Conditions of Use Concrete washout area best management practices are implemented on
construction projects where:
• Concrete is used as a construction material
■ It is not possible to dispose of all concrete wastewater and washout
off -site (ready mix plant, etc.).
• Concrete trucks, pumpers, or other concrete coated equipment are
washed on -site.
• Note: If less than 10 concrete trucks or pumpers need to be washed out
on -site, the washwater may be disposed of in a formed area awaiting
concrete or an upland disposal site where it will not contaminate
surface or ground water. The upland disposal site shall be at least 50
feet from sensitive areas such as storm drains, open ditches, or water
bodies, including wetlands.
Design and Implementation
Installation The following steps will help reduce stormwater pollution from concrete
Specifications wastes:
• Perform washout of concrete trucks off -site or in designated concrete
washout areas only.
• Do not wash out concrete trucks onto the ground, or into storm drains,
open ditches, streets, or streams.
• Do not allow excess concrete to be dumped on -site, except in
designated concrete washout areas.
• Concrete washout areas may be prefabricated concrete washout
containers, or self -installed structures (above -grade or below -grade).
• Prefabricated containers are most resistant to damage and protect
against spills and leaks. Companies may offer delivery service and
provide regular maintenance and disposal of solid and liquid waste.
• If self -installed concrete washout areas are used, below -grade
structures are preferred over above -grade structures because they are
less prone to spills and leaks.
• Self -installed above -grade structures should only be used if excavation
is not practical.
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-47
Education
• Discuss the concrete management techniques described in this BMP
with the ready -mix concrete supplier before any deliveries are made.
Educate employees and subcontractors on the concrete waste
management techniques described in this BMP.
• Arrange for contractor's superintendent or Certified Erosion and
Sediment Control Lead (CESCL) to oversee and enforce concrete
waste management procedures.
• A sign should be installed adjacent to each temporary concrete
washout facility to inform concrete equipment operators to utilize the
proper facilities.
Contracts
Incorporate requirements for concrete waste management into concrete
supplier and subcontractor agreements.
Location and Placement
• Locate washout area at least 50 feet from sensitive areas such as storm
drains, open ditches, or water bodies, including wetlands.
• Allow convenient access for concrete trucks, preferably near the area
where the concrete is being poured.
• If trucks need to leave a paved area to access washout, prevent track -
out with a pad of rock or quarry spalls (see BMP C105). These areas
should be far enough away from other construction traffic to reduce
the likelihood of accidental damage and spills.
• The number of facilities you install should depend on the expected
demand for storage capacity.
• On large sites with extensive concrete work, washouts should be
placed in multiple locations for ease of use by concrete truck drivers.
On -site Temporary Concrete Washout Facility, Transit Truck
Washout Procedures:
• Temporary concrete washout facilities shall be located a minimum of
50 ft from sensitive areas including storm drain inlets, open drainage
facilities, and watercourses. See Figures 4.1.7 and 4.1.8.
• Concrete washout facilities shall be constructed and maintained in
sufficient quantity and size to contain all liquid and concrete waste
generated by washout operations.
• Approximately 7 gallons of wash water are used to wash one truck
chute.
• Approximately 50 gallons are used to wash out the hopper of a
concrete pump truck.
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-48
• Washout of concrete trucks shall be performed in designated areas
only.
• Concrete washout from concrete pumper bins can be washed into
concrete pumper trucks and discharged into designated washout area
or properly disposed of off -site.
Once concrete wastes are washed into the designated area and allowed
to harden, the concrete should be broken up, removed, and disposed of
per applicable solid waste regulations. Dispose of hardened concrete
on a regular basis.
• Temporary Above -Grade Concrete Washout Facility
• Temporary concrete washout facility (type above grade) should be
constructed as shown on the details below, with a recommended
minimum length and minimum width of 10 ft, but with sufficient
quantity and volume to contain all liquid and concrete waste
generated by washout operations.
• Plastic lining material should be a minimum of 10 mil
polyethylene sheeting and should be free of holes, tears, or other
defects that compromise the impermeability of the material.
• Temporary Below -Grade Concrete Washout Facility
• Temporary concrete washout facilities (type below grade) should
be constructed as shown on the details below, with a recommended
minimum length and minimum width of 10 ft. The quantity and
volume should be sufficient to contain all liquid and concrete
waste generated by washout operations.
Lath and flagging should be commercial type.
Plastic lining material shall be a minimum of 10 mil polyethylene
sheeting and should be free of holes, tears, or other defects that
compromise the impermeability of the material.
• Liner seams shall be installed in accordance with manufacturers'
recommendations.
• Soil base shall be prepared free of rocks or other debris that may
cause tears or holes in the plastic lining material.
Maintenance Inspection and Maintenance
Standards
• Inspect and verify that concrete washout BMPs are in place prior to the
commencement of concrete work.
• Durina periods of concrete work, inspect daily to verify continued
performance.
• Check overall condition and performance.
• Check remaining capacity (% full).
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-49
• If using self -installed washout facilities, verify plastic liners are
intact and sidewalls are not damaged.
• If using prefabricated containers, check for leaks.
• Washout facilities shall be maintained to provide adequate holding
capacity with a minimum freeboard of 12 inches.
• Washout facilities must be cleaned, or new facilities must be
constructed and ready for use once the washout is 75% full.
• if the washout is nearing capacity, vacuum and dispose of the waste
material in an approved manlier.
• Do not discharge liquid or slurry to waterways, storm drains or
directly onto ground.
■ Do not use sanitary sewer without local approval.
• Place a secure, non -collapsing, non -water collecting cover over the
concrete washout facility prior to predicted wet weather to prevent
accumulation and overflow of precipitation.
• Remove and dispose of hardened concrete and return the structure
to a functional condition. Concrete may be reused on -site or hauled
away for disposal or recycling.
When you remove materials from the self -installed concrete washout,
build a new structure; or, if the previous structure is still intact, inspect
for signs of weakening or damage, and make any necessary repairs.
Re -line the structure with new plastic after each cleaning.
Removal of Temporary Concrete Washout Facilities
■ When temporary concrete washout facilities are no longer required for
the work, the hardened concrete, slurries and liquids shall be removed
and properly disposed of.
• Materials used to construct temporary concrete washout facilities shall
be removed from the site of the work and disposed of or recycled.
• Holes, depressions or other ground disturbance caused by the removal
of the temporary concrete washout facilities shall be backfilled,
repaired, and stabilized to prevent erosion.
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-50
SANDBAG
$0 enD�PI1lS37C
L[HWG
,
tTm
— BERM
LATH AND
'iOLTIDN AAA'
NOT TO SCALE
FLAGGING ON
3 SIDES �
II
� 3m MNIMUM -•�-I
0 (D ❑
VARIES D
SANDBAG!,
❑
C $�
10 nul PLASTIC LINING NOT TO SCALE
WK "BELOW GRADE
NOTES:
1. ACTUAL LAYOUT DETERMINED IN THE FIELD.
2. THE CONCRETE WASHOUT SIGN (SEE PAGE 6) SHALL
BE INSTALLED WITHIN 10 m OF THE TEMPORARY
CONCRETE WASHOUT FACILITY.
�- 10 and PL&M UNRIG
WOOD FRAME SECURELY
FASTENED AROUND
ENTIRE PERIMETER
WITH TWO STAKES
SECNDN w:
NOT TO SCALE
TWO -STACKED
❑
2x12 ROUGH —
WOOD FRAME
0
A
VARIES
O
O
l
f0 m7f PLPS IC
4
BERM
�-+ 3m MINIMUM --I
BM
NOT TO SCALE
TYPE 'ADM GPADE'
WRH WOOD PLANKS
Figure 4.1.7a — Concrete Washout Area
STAKE
(TYP-)
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-51
STRAW BALE
STAPLES
BINDING WIRE
(2 PER BALE)
10 mil PLASTIC LINING
WOOD OR METAL
NATIVE MATERIAL
STAKES (2 PER BALE)
` (OPTIONAL)
SECTION P=
140T TO SCALE
B
L_
VARIES
- 3m MINIMUM f- STAKE
(TYP,)
B'
J
1 S
STRAW BALE
10 mil PLASTIC LINING (TYP-)
B!tl
HOT TO SCALE
TYPE 'ABOVE GRADE'
WITH STRAW RAIES
1NOTES
1. ACTUAL LAYOUT DETERMINED IN THE FIELD.
2. THE CONCRETE WASHOUT SIGN (SEE FIG. 4-15)
SHALL HE INSTALLED WITHIN 10 m OF THE
TEMPORARY CONCRETE WASHOUT FACILRLY-
WPANSAIG4-14DW SAC 8-14-0I
PLYWOOD
1200 mm x610 mm
PAINTED WHITE
CONCRETE o i
BLACK LETTERS
WASHOUT I
_
150 mm HEIGHT
u
i
LAG SCREWS
(12.5 mm)
915 mm
WOOD POST
915 mm
(89 mm x 89 mm x 2.4 m)
CONCRETE WASHOUT
SIGN DETAIL
(OR EQUIVALENT)
50 m
200 mm II 3.05 mm WA
STEEL W11TE
STAPLE DETAIL
Figure 4.1.7b — Concrete Washout Area
Figure 4.1.8 — Prefabricated Concrete Washout Container w/Ramp
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-52
BMP C200: Interceptor Dike and Swale
Purpose
Provide a ridge of compacted soil, or a ridge with an upslope swale, at the
top or base of a disturbed slope or along the perimeter of a disturbed
construction area to convey stormwater. Use the dike and/or swale to
intercept the runoff from unprotected areas and direct it to areas where
erosion can be controlled. This can prevent storm runoff from entering the
work area or sediment -laden runoff from leaving the construction site.
Conditions of Use
Where the runoff from an exposed site or disturbed slope must be conveyed
to an erosion control facility which can safely convey the stormwater.
■ Locate upslope of a construction site to prevent runoff from entering
disturbed area.
When placed horizontally across a disturbed slope, it reduces the
amount and velocity of runoff flowing down the slope.
Locate downslope to collect runoff from a disturbed area and direct
water to a sediment basin.
Design and
• Dike and/or swale and channel must be stabilized with temporary or
Installation
permanent vegetation or other channel protection during construction.
Specifications
■ Channel requires a positive grade for drainage; steeper grades require
channel protection and check dams.
Review construction for areas where overtopping may occur.
• Can be used at top of new fill before vegetation is established.
• May be used as a permanent diversion channel to carry the runoff.
• Sub -basin tributary area should be one acre or less.
Design capacity for the peak flow from a 10-year, 24-hour storm,
assuming a Type I rainfall distribution, for temporary facilities.
Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an
approved continuous runoff model. For facilities that will also serve on
a permanent basis, consult the local government's drainage
requirements.
Interceptor dikes shall meet the following criteria:
Top Width 2 feet minimum.
Height 1.5 feet minimum on berm.
Side Slope 2H:1 V or flatter.
Grade Depends on topography, however, dike system minimum is
0.5%, and maximum is 1 %.
Compaction Minimum of 90 percent ASTM D698 standard proctor.
Volume H— Construction Stormwater Pollution Prevention - August 2012
4-57
Horizontal Spacing of Interceptor Dikes:
Average Slope
Slope Percent
Flowpath Length
20H:1V or less
3-5%
300 feet
(10 to 20)H:1 V
5-10%
200 feet
(4 to 10)H:1 V
10-25%
100 feet
(2 to 4)H:IV
25-50%
50 feet
Stabilization depends on velocity and reach
Slopes <5% Seed and mulch applied within 5 days of dike
construction (see BMP C 121. Mulching).
Slopes 5 - 40% Dependent on runoff velocities and dike materials.
Stabilization should be done immediately using either sod
or riprap or other measures to avoid erosion.
• The upslope side of the dike shall provide positive drainage to the dike
outlet. No erosion shall occur at the outlet. Provide energy dissipation
measures as necessary. Sediment -laden runoff must be released
through a sediment trapping facility.
• Minimize construction traffic over temporary dikes. Use temporary
cross culverts for channel crossing.
Interceptor swales shall meet the following criteria:
Bottom Width 2 feet minimum; the cross-section bottom shall be
level.
Depth 1-foot minimum.
Side Slope 2H: IV or flatter.
Grade Maximum 5 percent, with positive drainage to a
suitable outlet (such as a sediment pond).
Stabilization Seed as per BMP C120, Temporary and
Permanent Seeding, or BMP C202, Channel
Lining, 12 inches thick riprap pressed into the bank
and extending at least 8 inches vertical from the
bottom.
■ Inspect diversion dikes and interceptor swales once a week and after
every rainfall. Immediately remove sediment from the flow area.
• Damage caused by construction traffic or other activity must be
repaired before the end of each working day.
Check outlets and make timely repairs as needed to avoid gully formation.
When the area below the temporary diversion dike is permanently
stabilized, remove the dike and fill and stabilize the channel to blend with
the natural surface.
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-58
Treated 2"x10" may be abutted end to
Spreader must be level end for max. spreader length of 50'
6" min. 1" min.
11 j 6" min_ �I I I
=1 I Ed I I=1 11 1 I 1=1 11=1 I f=l 1 I=1 I I=l i I -I 11
I_! Ii i I_I! l—1 { I—i
18" min. rebar supports r
8' max. spacing
Figure 4.2.6 — Detail of Level Spreader
BMP C207: Check Dams
Purpose Construction of small dams across a swale or ditch reduces the velocity of
concentrated flow and dissipates energy at the check dam.
Conditions of Use Where temporary channels or permanent channels are not yet vegetated,
channel lining is infeasible, and/or velocity checks are required.
• Check dams may not be placed in streams unless approved by the State
Department of Fish and Wildlife. Check dams may not be placed in
wetlands without approval from a permitting agency.
Do not place check dams below the expected backwater from any
salmonid bearing water between October 1 and May 31 to ensure that
there is no loss of high flow refuge habitat for overwintering juvenile
salmonids and emergent salmonid fry.
Construct rock check dams from appropriately sized rock. The rock
used must be large enough to stay in place given the expected design
flow through the channel. The rock must be placed by hand or by
mechanical means (no dumping of rock to form dam) to achieve
complete coverage of the ditch or swale and to ensure that the center
of the dam is lower than the edges.
Check dams may also be constructed of either rock or pea -gravel filled
bags. Numerous new products are also available for this purpose. They
tend to be re -usable, quick and easy to install, effective, and cost
efficient.
Place check dams perpendicular to the flow of water.
■ The dam should form a triangle when viewed from the side. This
prevents undercutting as water flows over the face of the dam rather
than falling directly onto the ditch bottom.
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-73
• Before installing check dams impound and bypass upstream water
flow away from the work area. Options for bypassing include pumps,
siphons, or temporary channels.
• Check dams in association with sumps work more effectively at
slowing flow and retaining sediment than just a check dam alone. A
deep sump should be provided immediately upstream of the check
dam.
• In some cases, if carefully located and designed, check dams can
remain as permanent installations with very minor regrading. They
may be left as either spillways, in which case accumulated sediment
would be graded and seeded, or as check dams to prevent further
sediment from leaving the site.
• The maximum spacing between the dams shall be such that the toe of
the upstream dam is at the same elevation as the top of the downstream
dam.
• Keep the maximum height at 2 feet at the center of the dam.
• Keep the center of the check dam at least 12 inches lower than the
outer edges at natural ground elevation.
• Keep the side slopes of the check dam at 2H:1 V or flatter.
• Key the stone into the ditch banks and extend it beyond the abutments
a minimum of 18 inches to avoid washouts from overflow around the
dam.
• Use filter fabric foundation under a rock or sand bag check dam. If a
blanket ditch liner is used, filter fabric is not necessary. A piece of
organic or synthetic blanket cut to fit will also work for this purpose.
• In the case of grass -lined ditches and swales, all check dams and
accumulated sediment shall be removed when the grass has matured
sufficiently to protect the ditch or swale - unless the slope of the swale
is greater than 4 percent. The area beneath the check dams shall be
seeded and mulched immediately after dam removal.
• Ensure that channel appurtenances, such as culvert entrances below
check dams, are not subject to damage or blockage from displaced
stones. Figure 4.2.7 depicts a typical rock check dam.
Maintenance Check dams shall be monitored for performance and sediment
Standards accumulation during and after each runoff producing rainfall. Sediment
shall be removed when it reaches one half the sump depth.
• Anticipate submergence and deposition above the check dam and
erosion from high flows around the edges of the dam.
• If significant erosion occurs between dams, install a protective riprap
liner in that portion of the channel.
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-74
Approved as Ecology has approved products as able to meet the requirements of BMP
Equivalent C207. The products did not pass through the Technology Assessment
Protocol — Ecology (TAPE) process. Local jurisdictions may choose not
to accept this product approved as equivalent, or may require additional
testing prior to consideration for local use. The products are available for
review on Ecology's website at
http://www.ecy_wa Gov/pro&LamsYwq/stonnwater/newtech/equivalent.litml
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-75
BMP C220: Storm Drain Inlet Protection
Purpose Storm drain inlet protection prevents coarse sediment from entering
drainage systems prior to permanent stabilization of the disturbed area.
Conditions of Use Use storm drain inlet protection at inlets that are operational before
permanent stabilization of the disturbed drainage area. Provide protection
for all storm drain inlets downslope and within 500 feet of a disturbed or
construction area, unless conveying runoff entering catch basins to a
sediment pond or trap.
Also consider inlet protection for lawn and yard drains on new home
construction. These small and numerous drains coupled with lack of
gutters in new home construction can add significant amounts of sediment
into the roof drain system. If possible delay installing lawn and yard drains
until just before landscaping or cap these drains to prevent sediment from
entering the system until completion of landscaping. Provide 18-inches of
sod around each finished lawn and yard drain.
Table 4.2.2 lists several options for inlet protection. All of the methods for
storm drain inlet protection tend to plug and require a high frequency of
maintenance. Limit drainage areas to one acre or less. Possibly provide
emergency overflows with additional end -of -pipe treatment where
stormwater ponding would cause a hazard.
Volume H— Construction Stormwater Pollution Prevention - August 2012
4-79
Table 4.2.2
Storm Drain Inlet Protection
Applicable for
Type of Inlet
Emergency
Paved/ Earthen
Protection
Overflow
Surfaces
Conditions of Use
Drop Inlet Protection
Excavated drop inlet
Yes,
Earthen
Applicable for heavy flows. Easy
protection
temporary
to maintain. Large area
flooding will
Requirement: 30' X 30'/acre
occur
Block and gravel drop
Yes
Paved or Earthen
Applicable for heavy concentrated
inlet protection
flows. Will not pond.
Gravel and wire drop
No
Applicable for heavy concentrated
inlet protection
flows. Will pond. Can withstand
traffic.
Catch basin filters
Yes
Paved or Earthen
Frequent maintenance required.
Curb Inlet Protection
Curb inlet protection
Small capacity
Paved
Used for sturdy, more compact
with a wooden weir
overflow
installation.
Block and gravel curb
Yes
Paved
Sturdy, but limited filtration.
inlet protection
Culvert Inlet Protection
Culvert inlet sediment
18 month expected life.
trap
Design and Excavated Drop Inlet Protection - An excavated impoundment around the
Installation storm drain. Sediment settles out of the stormwater prior to entering the
Specifications storm drain.
• Provide a depth of 1-2 ft as measured from the crest of the inlet
structure.
• Slope sides of excavation no steeper than 2H:IV.
• Minimum volume of excavation 35 cubic yards.
• Shape basin to fit site with longest dimension oriented toward the
longest inflow area.
■ Install provisions for draining to prevent standing water problems.
• Clear the area of all debris.
• Grade the approach to the inlet uniformly.
• Drill weep holes into the side of the inlet.
• Protect weep holes with screen wire and washed aggregate.
• Seal weep holes when removing structure and stabilizing area.
Volume H— Construction Stormwater Pollution Prevention - August 2012
4-80
• Build a temporary dike, if necessary, to the down slope side of the
structure to prevent bypass flow.
Block and Gravel Filter - A barrier formed around the storm drain inlet
with standard concrete blocks and gravel. See Figure 4.2.8.
• Provide a height of 1 to 2 feet above inlet.
Recess the first row 2-inches into the ground for stability.
• Support subsequent courses by placing a 2x4 through the block
opening.
■ Do not use mortar.
• Lay some blocks in the bottom row on their side for dewatering the
pool.
• Place hardware cloth or comparable wire mesh with %-inch openings
over all block openings.
• Place gravel just below the top of blocks on slopes of 2H:1 V or flatter.
• An alternative design is a gravel donut.
• Provide an inlet slope of 3H:IV.
• Provide an outlet slope of 2H:IV.
• Provide al -foot wide level stone area between the structure and the
inlet.
■ Use inlet slope stones 3 inches in diameter or larger.
• Use gravel '/z- to 3/4-inch at a minimum thickness of 1-foot for the
outlet slope.
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-81
Plan View
Drain
Grate
A
Concrete
Block
avel
;kfill
Section A - A Concrete Block
Wire Screen or
_
Filter Fabric
Gravel Backfill Overflow ,
Water Ponding Height
_ .Water - "�'•'
Drop Inlet
•;
r
Notes:
1. Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less than 5%)
2. Excavate a basin of sufficient size adjacent to the drop inlet.
3. The top of the structure (ponding height) must be well below the ground elevation downslope to prevent
runoff from bypassing the inlet. A temporary dike may be necessary on the downslope side of the structure.
Figure 4.2.8 — Block and Gravel Filter
Gravel and Wire Mesh Filter - A gravel barrier placed over the top of the
inlet. This structure does not provide an overflow.
• Use a hardware cloth or comparable wire mesh with t/2-inch openings.
• Use coarse aggregate.
• Provide a height 1-foot or more, 18-inches wider than inlet on all
sides.
■ Place wire mesh over the drop inlet so that the wire extends a
minimum of 1-foot beyond each side of the inlet structure.
• Overlap the strips if more than one strip of mesh is necessary.
Volume II — Construction Stormwater Pollution Prevention - August 2012
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• Place coarse aggregate over the wire mesh.
■ Provide at least a 12-inch depth of gravel over the entire inlet opening
and extend at least 18-inches on all sides.
Catchbasin Filters — Use inserts designed by manufacturers for
construction sites. The limited sediment storage capacity increases the
amount of inspection and maintenance required, which may be daily for
heavy sediment loads. To reduce maintenance requirements combine a
catchbasin filter with another type of inlet protection. This type of inlet
protection provides flow bypass without overflow and therefore may be a
better method for inlets located along active rights -of -way.
+ Provides 5 cubic feet of storage.
• Requires dewatering provisions.
■ Provides a high -flow bypass that will not clog under normal use at a
construction site.
• Insert the catchbasin filter in the catchbasin just below the grating.
Curb Inlet Protection with Wooden Weir — Barrier formed around a curb
inlet with a wooden frame and gravel.
• Use wire mesh with '/z-inch openings.
• Use extra strength filter cloth.
• Construct a frame.
• Attach the wire and filter fabric to the frame.
• Pile coarse washed aggregate against wire/fabric.
• Place weight on frame anchors.
Block and Gravel Curb Inlet Protection — Barrier formed around a curb
inlet with concrete blocks and gravel. See Figure 4.2.9.
• Use wire mesh with 1/2-inch openings.
Place two concrete blocks on their sides abutting the curb at either side
of the inlet opening. These are spacer blocks.
■ Place a 2x4 stud through the outer holes of each spacer block to align
the front blocks.
Place blocks on their sides across the front of the inlet and abutting the
spacer blocks.
+ Place wire mesh over the outside vertical face.
• Pile coarse aggregate against the wire to the top of the barrier.
Curb and Gutter Sediment Barrier — Sandbag or rock berm (riprap and
aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See Figure
4.2.10.
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-83
• Construct a horseshoe shaped berm, faced with coarse aggregate if
using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inlet.
• Construct a horseshoe shaped sedimentation trap on the outside of the
berm sized to sediment trap standards for protecting a culvert inlet.
Maintenance • Inspect catch basin filters frequently, especially after storm events.
Standards Clean and replace clogged inserts. For systems with clogged stone
filters: pull away the stones from the inlet and clean or replace. An
alternative approach would be to use the clogged stone as fill and put
fresh stone around the inlet.
■ Do not wash sediment into storm drains while cleaning. Spread all
excavated material evenly over the surrounding land area or stockpile
and stabilize as appropriate.
Approved as Ecology has approved products as able to meet the requirements of BMP
Equivalent C220. The products did not pass through the Technology Assessment
Protocol — Ecology (TAPE) process. Local jurisdictions may choose not
to accept this product approved as equivalent, or may require additional
testing prior to consideration for local use. The products are available for
review on Ecology's website at
ft: //www. ecy.wa. p ov/p rog ram s/wq Isto nnwater/newtec h/eq u i vai ant . h ti n I
Volume II — Construction Stormwater Pollution Prevention - August 2012
4-84
Plan View
An
Sect.,.... .. tzumm)
3/<" Drain Gravel
(20mm)
Ponding Height
Concrete Block
Overflow
Curb Inlet//�
Wire Screen or ;f•.' \ ;//�
Filter Fabric �\
a Wood Stud
Catch Basin
r'�
(100x50 Timber Stud)
NOTES:
1. Use block and gravel type sediment barrier when curb inlet is located in gently sloping street segment,
where water can pond and allow sediment to separate from runoff.
2. Barrier shall allow for overflow from severe storm event.
3. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed
from the traveled way immediately.
Figure 4.2.9 — Block and Gravel Curb Inlet Protection
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-85
Plan View
Back of Sidewalk
Burlap Sacks to Catch Basin
Overlap onto Curb
Curb Inlet
Back of Curb'
RUNOFF
RUNOFF SPILLWAY
�X
Gravel Filled Sandbags
Stacked Tightly
NOTES:
1. Place curb type sediment barriers on gently sloping street segments, where water can pond and allow
sediment to separate from runoff.
2. Sandbags of either burlap or woven 'geotextile' fabric, are filled with gravel, layered and packed tightly.
3. Leave a one sandbag gap in the top row to provide a spillway for overflow.
4. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from
the traveled way immediately.
Figure 4.2.10 — Curb and Gutter Barrier
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-86
BMP C240: Sediment Trap
Purpose A sediment trap is a small temporary ponding area with a gravel outlet
used to collect and store sediment from sites cleared and/or graded during
construction. Sediment traps, along with other perimeter controls, shall be
installed before any land disturbance takes place in the drainage area.
Conditions of Use Prior to leaving a construction site, stormwater runoff must pass through a
sediment pond or trap or other appropriate sediment removal best
management practice. Non -engineered sediment traps may be used on -site
prior to an engineered sediment trap or sediment pond to provide
additional sediment removal capacity.
It is intended for use on sites where the tributary drainage area is less than
3 acres, with no unusual drainage features, and a projected build -out time
of six months or less. The sediment trap is a temporary measure (with a
design life of approximately 6 months) and shall be maintained until the
site area is permanently protected against erosion by vegetation and/or
structures.
Sediment traps and ponds are only effective in removing sediment down
to about the medium silt size fraction. Runoff with sediment of finer
grades (fine silt and clay) will pass through untreated, emphasizing the
need to control erosion to the maximum extent first.
Whenever possible, sediment -laden water shall be discharged into on -site,
relatively level, vegetated areas (see BMP C234 — Vegetated Strip). This
is the only way to effectively remove fine particles from runoff unless
chemical treatment or filtration is used. This can be particularly useful
after initial treatment in a sediment trap or pond. The areas of release must
be evaluated on a site -by -site basis in order to determine appropriate
locations for and methods of releasing runoff. Vegetated wetlands shall
not be used for this purpose. Frequently, it may be possible to pump water
from the collection point at the downhill end of the site to an upslope
vegetated area. Pumping shall only augment the treatment system, not
replace it, because of the possibility of pump failure or runoff volume in
excess of pump capacity.
All projects that are constructing permanent facilities for runoff quantity
control should use the rough -graded or final -graded permanent facilities
for traps and ponds. This includes combined facilities and infiltration
facilities. When permanent facilities are used as temporary sedimentation
facilities, the surface area requirement of a sediment trap or pond must be
met. If the surface area requirements are larger than the surface area of the
permanent facility, then the trap or pond shall be enlarged to comply with
the surface area requirement. The permanent pond shall also be divided
into two cells as required for sediment ponds.
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-101
Either a permanent control structure or the temporary control structure
(described in BMP C241, Temporary Sediment Pond) can be used. If a
permanent control structure is used, it may be advisable to partially restrict
the lower orifice with gravel to increase residence time while still allowing
dewatering of the pond. A shut-off valve may be added to the control
structure to allow complete retention of stormwater in emergency
situations. In this case, an emergency overflow weir must be added.
A skimmer may be used for the sediment trap outlet if approved by the
Local Permitting Authority.
Design and ■ See Fivures 4.2.16 and 4.2.17 for details
Installation , If permanent runoff control facilities are part of the project, they
Specifications
should be used for sediment retention.
■ To determine the sediment trap geometry, first calculate the design
surface area (SA) of the trap, measured at the invert of the weir. Use
the following equation:
SA = FS(Q21VS)
where
Q2 = Design inflow based on the peak discharge from the
developed 2-year runoff event from the contributing
drainage area as computed in the hydrologic analysis. The
10-year peak flow shall be used if the project size, expected
timing and duration of construction, or downstream
conditions warrant a higher level of protection. If no
hydrologic analysis is required, the Rational Method may
be used.
Vs = The settling velocity of the soil particle of interest. The
0.02 mm (medium silt) particle with an assumed density of
2.65 g/cm3 has been selected as the particle of interest and
has a settling velocity (Vs) of 0.00096 ft/sec.
FS = A safety factor of 2 to account for non -ideal settling.
Therefore, the equation for computing surface area becomes:
SA = 2 x Q2/0.00096 or
2080 square feet per cfs of inflow
Note: Even if permanent facilities are used, they must still have a
surface area that is at least as large as that derived from the above
formula. If they do not, the pond must be enlarged.
• To aid in determining sediment depth, all sediment traps shall have a
staff gauge with a prominent mark 1-foot above the bottom of the trap.
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-102
• Sediment traps may not be feasible on utility projects due to the
limited work space or the short-term nature of the work. Portable tanks
may be used in place of sediment traps for utility projects.
Maintenance Sediment shall be removed from the trap when it reaches 1-foot in
Standards depth.
Any damage to the pond embankments or slopes shall be repaired.
Surface area determined �4' Min. _I
at top of weir
— — — —�
—� 1' Min. Overflew
1' in. TT �—
�?' 1' Min,
T1_5'Min. �_1.., . . t�T
Flat Bottom
'/<" - 1.5" ` 2"-4" Rock
�Rap j
Washed gravel
Note: Trap may be formed by berm or by Geotextile
partial or complete excavation
Discharge to stabilized
conveyance, outlet, or
level spreader
Figure 4.2.16 — Cross Section of Sediment Trap
�-� 6' Min. y{
1' Min. depth overflow spillway
hI I lhl 11—Ili—III—ll i l- Q p 1 {! 11 1=1 I I —I I ,�I I I --I II
Native soil or y — 4 '`"�lin- 1' depth
compacted backfill — ! .' - :.:..: -H I' 2"-4"' rock
Geotextile -11 E—d I IEEE; I I-1 I I^I I I=1 I!=I I EJ I -1 I l Min. 1' depth 3/4"-1.5"
�[ 11 11!-I 11=1 11-f 11 11 I=1 11=11 l-1 washed gravel
Figure 4.2.17 — Sediment Trap Outlet
Volume II— Construction Stormwater Pollution Prevention - August 2012
4-103
BMP C252: High pH Neutralization Using CO2
Purpose When pH levels in stormwater rise above 8.5 it is necessary to lower the
pH levels to the acceptable range of 6.5 to 8.5, this process is called pH
neutralization. pH neutralization involves the use of solid or compressed
carbon dioxide gas in water requiring neutralization. Neutralized
stormwater may be discharged to surface waters under the General
Construction NPDES permit.
Neutralized process water such as concrete truck wash -out, hydro -
demolition, or saw -cutting slurry must be managed to prevent discharge to
surface waters. Any stormwater contaminated during concrete work is
considered process wastewater and must not be discharged to surface
waters.
Reason for pH Neutralization:
A pH level range of 6.5 to 8.5 is typical for most natural watercourses, and
this neutral pH is required for the survival of aquatic organisms. Should
the pH rise or drop out of this range, fish and other aquatic organisms may
become stressed and may die.
Calcium hardness can contribute to high pH values and cause toxicity that
is associated with high pH conditions. A high level of calcium hardness in
waters of the state is not allowed.
The water quality standard for pH in Washington State is in the range of
6.5 to 8.5. Ground water standard for calcium and other dissolved solids in
Washington State is less than 500 mg/1.
Conditions of Use Causes of HighyH:
High pH at construction sites is most commonly caused by the contact of
stormwater with poured or recycled concrete, cement, mortars, and other
Portland cement or lime containing construction materials. (See BMP
C 151: Concrete Handline for more information on concrete handling
procedures). The principal caustic agent in cement is calcium hydroxide
(free lime).
Advantages of CO2 SnarginL,:
• Rapidly neutralizes high pH water.
• Cost effective and safer to handle than acid compounds.
• CO2 is self -buffering. It is difficult to overdose and create harmfully
low pH levels.
Material is readily available.
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-123
The Chemical Process:
When carbon dioxide (CO2) is added to water (H2O), carbonic acid
(H2CO3) is formed which can further dissociate into a proton (H+) and a
bicarbonate anion (HCO3-) as shown below:
CO2+ H2O H H2CO3 H H++ HCO3
The free proton is a weak acid that can lower the pH. Water temperature
has an effect on the reaction as well. The colder the water temperature is
the slower the reaction occurs and the warmer the water temperature is the
quicker the reaction occurs. Most construction applications in Washington
State have water temperatures in the 50°F or higher range so the reaction
is almost simultaneous.
Design and Treatment Process:
Installation High pH water may be treated using continuous treatment, continuous
Specifications discharge systems. These manufactured systems continuously monitor
influent and effluent pH to ensure that pH values are within an acceptable
range before being discharged. All systems must have fail safe automatic
shut off switches in the event that pH is not within the acceptable
discharge range. Only trained operators may operate manufactured
systems. System manufacturers often provide trained operators or training
on their devices.
The following procedure may be used when not using a continuous
discharge system:
1. Prior to treatment, the appropriate jurisdiction should be notified in
accordance with the regulations set by the jurisdiction.
2. Every effort should be made to isolate the potential high pH water in
order to treat it separately from other stormwater on -site.
3. Water should be stored in an acceptable storage facility, detention
pond, or containment cell prior to treatment.
4. Transfer water to be treated to the treatment structure. Ensure that
treatment structure size is sufficient to hold the amount of water that is
to be treated. Do not fill tank completely, allow at least 2 feet of
freeboard.
5. The operator samples the water for pH and notes the clarity of the
water. As a rule of thumb, less CO2 is necessary for clearer water. This
information should be recorded.
6. In the pH adjustment structure, add CO2 until the pH falls in the range
of 6.9-7.1. Remember that pH water quality standards apply so
adjusting pH to within 0.2 pH units of receiving water (background
pH) is recommended. It is unlikely that pH can be adjusted to within
0.2 pH units using dry ice. Compressed carbon dioxide gas should be
introduced to the water using a carbon dioxide diffuser located near
Volume II— Construclion Stormwater Pollution Prevention - August 2012
4-124
the bottom of the tank, this will allow carbon dioxide to bubble up
through the water and diffuse more evenly.
7. Slowly discharge the water making sure water does not get stirred up
in the process. Release about 80% of the water from the structure
leaving any sludge behind.
8. Discharge treated water through a pond or drainage system.
9. Excess sludge needs to be disposed of properly as concrete waste. If
several batches of water are undergoing pH treatment, sludge can be
left in treatment structure for the next batch treatment. Dispose of
sludge when it fills 50% of tank volume.
Sites that must implement flow control for the developed site must also
control stormwater release rates during construction. All treated
stormwater must go through a flow control facility before being released
to surface waters which require flow control.
Maintenance Safety and Materials Handlhii!:
Standards All equipment should be handled in accordance with OSHA rules and
regulations.
Follow manufacturer guidelines for materials handling.
Operator Records:
Each operator should provide:
• A diagram of the monitoring and treatment equipment.
• A description of the pumping rates and capacity the treatment
equipment is capable of treating.
Each operator should keep a written record of the following:
■ Client name and phone number.
• Date of treatment.
• Weather conditions.
• Project name and location.
• Volume of water treated.
• pH of untreated water.
• Amount of CO2 needed to adjust water to a pH range of 6.9-7.1.
pH of treated water.
Discharge point location and description.
A copy of this record should be given to the client/contractor who should
retain the record for three years.
Volume II — Construction Stormwater Pollution Prevention - August 2012
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BMP C253: pH Control for High pH Water
Purpose When pH levels in stormwater rise above 8.5 it is necessary to lower the
pH levels to the acceptable range of 6.5 to 8.5, this process is called pH
neutralization. Stormwater with pH levels exceeding water quality
standards may be treated by infiltration, dispersion in vegetation or
compost, pumping to a sanitary sewer, disposal at a permitted concrete
batch plant with pH neutralization capabilities, or carbon dioxide sparging.
BMP C252 gives guidelines for carbon dioxide sparging.
Reason for pH Neutralization:
A pH level range of 6.5 to 8.5 is typical for most natural watercourses, and
this pH range is required for the survival of aquatic organisms. Should the
pH rise or drop out of this range, fish and other aquatic organisms may
become stressed and may die.
Conditions of Use Causes of High H:
High pH levels at construction sites are most commonly caused by the
contact of stormwater with poured or recycled concrete, cement, mortars,
and other Portland cement or lime containing construction materials. (See
BMP C 151: Concrete Handlin for more information on concrete handling
procedures). The principal caustic agent in cement is calcium hydroxide
(free lime).
Design and Disposal Methods:
Installation Infiltration
Specifications
• Infiltration is only allowed if soil type allows all water to infiltrate (no
surface runoff) without causing or contributing to a violation of
surface or ground water quality standards.
Infiltration techniques should be consistent with Volume V, Chapter 7
Dispersion
Use BMP T5.30 Full Dispersion
Sanitary Sewer Disposal
• Local sewer authority approval is required prior to disposal via the
sanitary sewer.
Concrete Batch Plant Disposal
• Only permitted facilities may accept high pH water.
• Facility should be contacted before treatment to ensure they can accept
the high pH water.
Stormwater Discharge
Any pH treatment options that generate treated water that must be
discharged off site are subject to flow control requirements. Sites that
must implement flow control for the developed site must also control
Volume II — Construction Stormwater Pollution Prevention -August 2012
4-126
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Construction Stormwater Site Inspection Form
Project Name
Permit #
Inspection Date
Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre
Print Name:
Approximate rainfall amount since the last inspection (in inches):
Approximate rainfall amount in the last 24 hours (in inches):
Current Weather Clear L] Cloudy F-J Mist ❑ Rain ❑ Wind ❑ Fog
A. Type of inspection: Weekly u Post Storm Event Ll Other n
B. Phase of Active Construction (check all that apply):
Time
Pre Construction/installation of erosion/sediment controls Clearing/Demo/Grading Infrastructure/storm/roads
Concrete pours Vertical Construction/buildings Utilities
Offsite improvements Site temporary stabilized Final stabilization
C. Questions:
1. Were all areas of construction and discharge points inspected?
Yes
No
2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen
Yes
No
3. Was a water quality sample taken during inspection? (refer to permit conditions S4 & S5)
Yes
No
4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less?*
Yes
No
5. If yes to #4 was it reported to Ecology?
Yes
No
6. Is pH sampling required? pH range required is 6.5 to 8.5.
Yes
No
If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken,
and when.
*If answering yes to # 4 record NTU/Transparency with continual sampling daily until turbidity is 25 NTU or less/ transparency is 33
cm or greater.
Sampling Results:
Date:
Parameter
Method (circle one)
Result
Other/Note
NTU
cm
I pH
Turbidity
tube, meter, laboratory
pH
Paper, kit, meter
Page 1
Construction Stormwater Site Inspection Form
D. Check the observed status of all items. Provide "Action Required "details and dates.
Element #
Inspection
BMPs
BMP needs
BMP
Action
Inspected
maintenance
failed
required
(describe in
jy—eTo
n/a
section F)
1
Before beginning land disturbing
Clearing
activities are all clearing limits,
Limits
natural resource areas (streams,
wetlands, buffers, trees) protected
with barriers or similar BMPs? (high
visibility recommended)
2
Construction access is stabilized
Construction
with quarry spalls or equivalent
Access
BMP to prevent sediment from
being tracked onto roads?
Sediment tracked onto the road
way was cleaned thoroughly at the
end of the day or more frequent as
necessary.
3
Are flow control measures installed
Control Flow
to control stormwater volumes and
Rates
velocity during construction and do
they protect downstream
properties and waterways from
erosion?
If permanent infiltration ponds are
used for flow control during
construction, are they protected
from siltation?
4
All perimeter sediment controls
Sediment
(e.g. silt fence, wattles, compost
Controls
socks, berms, etc.) installed, and
maintained in accordance with the
Stormwater Pollution Prevention
Plan (SWPPP).
Sediment control BMPs (sediment
ponds, traps, filters etc.) have been
constructed and functional as the
first step of grading.
Stormwater runoff from disturbed
areas is directed to sediment
removal BMP.
5
Have exposed un-worked soils
Stabilize
been stabilized with effective BMP
Soils
to prevent erosion and sediment
deposition?
Page 2
Construction Stormwater Site Inspection Form
Element #
Inspection
BMPs
BMP needs
BMP
Action
Inspected
maintenance
failed
required
yes
no
n/a
(describe in
section F)
5
Are stockpiles stabilized from erosion,
Stabilize Soils
protected with sediment trapping
Cont.
measures and located away from drain
inlet, waterways, and drainage
channels?
Have soils been stabilized at the end of
the shift, before a holiday or weekend
if needed based on the weather
forecast?
Has stormwater and ground water
6
been diverted away from slopes and
Protect
disturbed areas with interceptor dikes,
Slopes
pipes and or swales?
Is off -site storm water managed
separately from stormwater generated
on the site?
Is excavated material placed on uphill
side of trenches consistent with safety
and space considerations?
Have check dams been placed at
regular intervals within constructed
channels that are cut down a slope?
7
Storm drain inlets made operable
Drain Inlets
during construction are protected.
Are existing storm drains within the
influence of the project protected?
8
Have all on -site conveyance channels
Stabilize
been designed, constructed and
Channel and
stabilized to prevent erosion from
Outlets
expected peak flows?
Is stabilization, including armoring
material, adequate to prevent erosion
of outlets, adjacent stream banks,
slopes and downstream conveyance
systems?
9
Are waste materials and demolition
Control
debris handled and disposed of to
Pollutants
prevent contamination of stormwater?
Has cover been provided for all
chemicals, liquid products, petroleum
products, and other material?
Has secondary containment been
provided capable of containing 110%
of the volume?
Were contaminated surfaces cleaned
immediately after a spill incident?
Were BMPs used to prevent
contamination of stormwater by a pH
modifying sources?
Page 3
Construction Stormwater Site Inspection Form
Element #
Inspection
BMPs
BMP needs
BMP
Action
Inspected
maintenance
failed
required
(describe in
yes
no
n/a
section F)
9
Wheel wash wastewater is handled
Cont.
and disposed of properly.
10
Concrete washout in designated areas.
Control
No washout or excess concrete on the
Dewatering
ground.
Dewatering has been done to an
approved source and in compliance
with the SWPPP.
Were there any clean non turbid
dewatering discharges?
11
Are all temporary and permanent
Maintain
erosion and sediment control BMPs
BMP
maintained to perform as intended?
12
Has the project been phased to the
Manage the
maximum degree practicable?
Project
Has regular inspection, monitoring and
maintenance been performed as
required by the permit?
Has the SWPPP been updated,
implemented and records maintained?
13
Is all Bioretention and Rain Garden
Protect LID
Facilities protected from
sedimentation with appropriate BMPs?
Is the Bioretention and Rain Garden
protected against over compaction of
construction equipment and foot
traffic to retain its infiltration
capabilities?
Permeable pavements are clean and
free of sediment and sediment laden -
water runoff. Muddy construction
equipment has not been on the base
material or pavement.
Have soiled permeable pavements
been cleaned of sediments and pass
infiltration test as required by
stormwater manual methodology?
Heavy equipment has been kept off
existing soils under LID facilities to
retain infiltration rate.
E. Check all areas that have been inspected. ✓
All in place BMPs All disturbed soils ❑ All concrete wash out area All material storage areas
All discharge locations All equipment storage areas ❑ All construction entrances/exits El
Page 4
Construction Stormwater Site Inspection Form
F. Elements checked "Action Required" (section D) describe corrective action to be taken. List the element number;
be specific on location and work needed. Document, initial, and date when the corrective action has been completed
and inspected.
Element Description and Location Action Required Completion Initials
# Date
Attach additional page if needed
Sian the following certification:
"I certify that this report is true, accurate, and complete, to the best of my knowledge and belief"
Inspected by: (print)
Title/Qualification of Inspector:
(Signature)
Date:
Page 5
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