23-103436-UP-CSWPPP-07-25-2023
CONSTRUCTION STORMWATER
POLLUTION PREVENTION PLAN
FOR
ASSA 2
RETAIL BUILDING
FEDERAL WAY, WASHINGTON
JUNE 2023
Prepared For:
Daniel Yu (Assa 2, Inc.)
1420 348th St.
Federal Way, 98003
Prepared By:
Jamey Barr, Design Engineer
Approved By:
Brett Allen, P.E., Project Engineer
PO Box 949
Gig Harbor, WA 98335
(253) 857-5454
Project # 23-015
I hereby state that this Construction Stormwater Pollution Prevention Plan for ASSA 2 Retail Building has been prepared by me or
under my supervision and meets the standard of care and expertise that is usual and customary in this community of professional
engineers. I understand that King County does not and will not assume liability for the sufficiency, suitability or performance of
drainage facilities prepared by Contour Engineering LLC. This analysis is based on data and records either supplied to, or obtained
by, Contour Engineering, LLC. These documents are referenced within the text of the analysis. The analysis has been prepared
utilizing procedures and practices within the standard accepted practices of the industry.
1
TABLE OF CONTENTS
PROJECT DESCRIPTION ............................................................................................................. 2
EXISTING CONDITIONS SUMMARY ........................................................................................... 2
CONSTRUCTION STORMWATER POLLUTION PREVENTION ELEMENTS .................................... 3
Element #1: Clearing Limits .......................................................................................................... 4
Element #2: Cover Measures ........................................................................................................ 4
Element #3: Perimeter Protection ................................................................................................. 5
Element #4: Traffic Area Stabilization ............................................................................................ 5
Element #5: Sediment Retention................................................................................................... 5
Element #6: Surface Water Collection ........................................................................................... 6
Element #7: Dewatering Control ................................................................................................... 6
Element #8: Dust Control ............................................................................................................. 6
Element #9: Flow Control ............................................................................................................. 7
Element #10: Control Pollutants .................................................................................................... 7
Element #11: Protect Existing and Proposed Flow Control BMPs ..................................................... 8
Element #12: Maintain BMPs ........................................................................................................ 8
Element #13: Manage the Project ................................................................................................. 8
CONSTRUCTION SEQUENCE .................................................................................................................. 10
CONSTRUCTION SCHEDULE .................................................................................................................. 10
FINANCIAL/OWNERSHIP RESPONSIBILITIES .............................................................................................. 11
RESPONSIBLE PARTY .......................................................................................................................... 11
Appendix A Plan Exhibits
Appendix B Applicable BMPs
2
PROJECT DESCRIPTION
Purpose and Scope
This Construction Pollution Prevention Plan (CSWPPP) accompanies the ASSA 2 Retail
Building submittal application. The site is located within a portion of the Northeast quarter
of the Southeast quarter of Section 20, Township 21 North, Range 4 East, W.M. The
proposed project includes the construction of a new commercial building on a site with
access from 348th South St. The site was previously prepared for the new building with
the adjacent building, including parking and utility connections.
The 2021 King County, Washington Surface Water Design Manual (KCSWDM),
Washington Surface Water Design Manual, the King County Stormwater Pollution
Prevention Manual, and the latest edition of the LID Technical Guidance Manual for
Puget Sound establish the design methodology and design criteria used for this project.
The following is a description of pertinent site information associated with the proposed
project:
Site Address – 1416 S. 348th St., Federal Way, WA. 98003
Tax Parcel Number – 2021049088
Parcel Area – 18,911 sq. ft. (0.43 acres)
Per Figure 1.1.2.A of the 2021 KCSWDM, this project meets the criteria for Full Drainage
Review. Therefore, all nine of the core requirements and all five of the special
requirements will be addressed as part of this project. See Appendix A for a copy of the
TIR worksheet, maps, and exhibits of the site location
EXISTING CONDITIONS
Topography
The site is graded flat with a paved parking lot in the existing condition due to it’s
previous development of the adjacent building and consideration for this future building
development.
Soils
The Natural Resources Conservation Service (NRCS) soil survey identified as Everett
Alderwood soil (EwC) with 0% slope.
Groundcover
The property is covered with an mostly paved parking or otherwise covered in hard
surface with minimal amounts of landscaping in the area of the building pad. The offsite
areas are likewise developed or provide small, landscaped areas.
3
Critical and Sensitive Areas
SLOPES
No steep slopes exist on or adjacent to the site.
STREAMS
No identified streams exist on or adjacent to the site.
WETLANDS
No identified wetlands exist on or adjacent to the site.
AQUIFER RECHARGE
The property is not located in an aquifer recharge area.
FLOODPLAIN
The proposed development is not located within 300-ft of any identified floodplains.
SLOPES
No steep slopes exist on or adjacent to the site.
STREAMS
No identified streams exist on or adjacent to the site.
WETLANDS
No identified wetlands exist on or adjacent to the site.
AQUIFER RECHARGE
The property is not located in an aquifer recharge area.
FLOODPLAIN
The proposed development is not located within 300-ft of any identified floodplains.
Other Existing Site Information
Not applicable.
Storm Drainage and Utilities
Stormwater drainage infrastructure was identified onsite during site survey. The water
quality mitigation has been provided for previously constructed pollution generating
surfaces.
CONSTRUCTION STORMWATER POLLUTION PREVENTION ELEMENTS
The Elements have been addressed and the appropriate BMPs have been incorporated
into the Civil Plans, See Appendix A. Appendix B contains the BMPs used in the sites
TESC Plan along with some others that may be needed if site conditions change as
construction progresses. The list of BMPs was taken from the 2021 King County Surface
4
Water Design Manual and Volume II Chapter 4 of the 2019 Department of Ecology
Stormwater Management Manual for Western Washington and are as follows:
o BMP D.2.1: ESC Measures
o BMP D.2.1.1: Clearing Limits
o BMP D.2.1.1.1: Plastic or Metal Fence
o BMP D.2.1.2.2: Mulching
o BMP D.2.1.2.3: Nets and Blankets
o BMP D.2.1.2.4: Plastic Covering
o BMP D.2.1.2.5: Straw Wattles
o BMP D.2.1.2.6: Temporary and Permanent Seeding
o BMP D.2.1.3.1: Silt Fence
o BMP D.2.1.4.1: Stabilized Construction Entrance
o BMP D.2.1.8: Dust Control
o BMP D.2.3.6: Road and Utility Compliance
If necessary, contractor shall employ any additional BMPs per Appendix D of the
KCSWDM or Appendix E of the DOE Manual to provide proper erosion, sediment, and
pollutant control onsite.
Element #1: Clearing Limits
Prior to beginning land disturbing activities, including clearing and grading, clearly
delineate all clearing limits, sensitive areas and their buffers, and trees (if any) that are
to be preserved within the construction area. The clearing limits are typically marked
with the Silt Fencing, construction fence or other appropriate BMP; however, a
continuous length of brightly colored survey tape should be sufficient for the areas
where silt fence is not required. The tape should be supported by vegetation or stakes
at a height of 3-6 ft. The ESC Plan shows the clearing limits for the project.
Element #2: Cover Measures
Exposed and un-worked soils, such as soil stockpiles, shall be stabilized by application
of effective erosion control measures that protect the soil from the erosive forces of
raindrops, flowing water, and wind. Such measures include Plastic Covering and
Temporary and Permanent Seeding.
Selected soil stabilization measures shall be appropriate for the time of year, site
conditions, estimated duration of use, and the water quality impacts that stabilization
agents may have on downstream waters or ground water.
The “Wet Season” is from October 1 to April 30. Within this period, no soils shall remain
exposed and un-worked for more than 2 days. The “Dry Season” is from May 1 to
5
September 30. Within this period, no soils shall remain exposed and un-worked for
more than 7 days. This stabilization requirement applies to all soils on-site, whether at
final grade or not. Soils shall be stabilized at the end of each shift before a holiday or
weekend (if needed) based on the weather forecast.
Element #3: Perimeter Protection
Perimeter protection to filter sediment from sheetwash shall be located downslope of all
disturbed areas and shall be installed prior to upslope grading. Perimeter protection
includes the use of vegetated strips as well as, constructed measures, such as silt
fences, fiber rolls, sand/gravel barriers, brush or rock filters, triangular silt dikes and
other methods. During the wet season, 50 linear feet of silt fence (and the necessary
stakes) per acre of disturbed area must be stockpiled on site.
Silt Fence is specified in some areas due to topography and length of native vegetation
area to halt any sediment laden stormwater from leaving the site perimeter. The
majority of the disturbed area can be protected with a vegetated strip as depicted on
the TESC Plan Additional silt fence shall be added as needed. Straw Wattles can be
used in place of silt fence if installed per BMP and properly maintained.
Element #4: Traffic Area Stabilization
Unsurfaced entrances, roads, and parking areas used by construction traffic shall be
stabilized to minimize erosion and tracking of sediment off site. Stabilized construction
entrances shall be installed as the first step in clearing and grading. At the County's
discretion, road and parking area stabilization is not required during the dry season
(unless dust is a concern) or if the site is underlain by coarse-grained soils. Roads and
parking areas shall be stabilized immediately after initial grading.
Construction vehicle ingress and egress shall be limited to the Stabilized Construction
Entrances (BMP D2.1.4) shown on the TESC Plan (Figure C.3.1.A). The entrance shall
be stabilized with quarry spalls or crushed rock to minimize the tracking of sediment
onto public roads per the approved plan and ESC Measure D2.1.4. It shall be
maintained and repaired as needed.
Sediment shall be removed from roads and transported to a controlled sediment
disposal area. No street washing of sediments to the storm drain system will be
allowed. If deemed necessary, a Wheel Wash (BMP D.3.4.3) may be needed or an
approved mobile wheel wash system may be utilized.
Element #5: Sediment Retention
It is anticipated that the site can be treated solely with perimeter protection which
includes silt fencing and vegetated strips. If sedimentation becomes an issue, it is
recommended that the project install further perimeter protection BMPs and stabilize
disturbed areas prior to constructing a sediment pond or trap.
6
Element #6: Surface Water Collection
It is anticipated that the site can be treated solely with perimeter protection which
includes silt fencing and vegetated strips. It is anticipated that much of the runoff from
the site will be un-concentrated sheet flow.
Element #7: Dewatering Control
Any runoff generated by dewatering shall be treated through construction of a sediment
trap (D.2.1.5.1) when there is sufficient space or by releasing the water to a well
vegetated, gently sloping area. Since pumps are used for dewatering, it may be
possible to pump the sediment-laden water well away from the surface water so that
vegetation can be more effectively utilized for treatment. Discharge of sediment-laden
water from dewatering activities to surface and storm waters is prohibited. If
dewatering occurs from areas where the water has come in contact with new concrete,
such as tanks, vaults, or foundations, the pH of the water must be monitored and must
be neutralized prior to discharge. Clean non-turbid dewatering water, such as well point
ground water can be discharged to systems tributary to, or directly to surface waters
provided the flows are controlled so no erosion or flooding occurs. Clean water must
not be routed through a stormwater sediment pond. Highly turbid or contaminated
dewatering water must be handled separately from stormwater.
It is anticipated that dewatering will not be needed. If dewatering is needed the
following guidance is provided.
Discharge foundation, vault, and trench dewatering water that has similar
characteristics to site stormwater runoff into a controlled conveyance system prior to
discharge to a stabilized outfall location.
Clean, non-turbid dewatering water, such as well-point groundwater, can be discharged
to systems tributary to state surface waters, provided the dewatering flow does not
cause erosion or flooding of receiving waters. These clean waters should not be routed
through stormwater sediment ponds/tanks.
Element #8: Dust Control
Preventative measures to minimize the wind transport of soil shall be taken when a
traffic hazard may be created or when sediment transported by wind is likely to be
deposited in water resources or adjacent properties.
Water is the most common dust control (or palliative) used in the area. When using
water for dust control, the exposed soils shall be sprayed until wet, but runoff shall not
be generated by spraying. Calcium chloride, Magnesium chloride, Lignin derivatives,
Tree Resin Emulsions, and Synthetic Polymer Emulsions may also be used for dust
control. Exposed areas shall be re-sprayed as needed. Oil shall not be used for dust
control.
7
Element #9: Flow Control
It is anticipated that the site can be treated solely with perimeter protection which
includes silt fencing and vegetated strips. If a flow control facility is required, the
contractor or owner should contact the project engineer.
Element #10: Control Pollutants
Stormwater pollution prevention (SWPPS) measures are required to prevent, reduce, or
eliminate the discharge of pollutants to onsite or adjacent stormwater systems or
watercourses from construction-related activities such as materials delivery and storage,
onsite equipment fueling and maintenance, demolition of existing buildings and
disposition of demolition materials and other waste, and concrete handling, washout
and disposal.
Secondary containment is required for hazardous material storage, dispensing,
refueling, use and handling areas.
Spill kits containing adequate response materials must be maintained to ensure the
immediate containment and cleanup of any release of hazardous substances used at
the construction site.
Leaking construction vehicles and equipment shall be removed immediately or repaired
on-site immediately, provided the leakage is completely contained and cleaned up.
Releases shall immediately be contained, cleaned up and reported to (425) 649-7000.
Designate a person who will be on-site and responsible for spill prevention, handling of
hazardous materials and cleanup of spills.
Maintenance and repair of heavy equipment and vehicles involving oil changes,
hydraulic system drain down, solvent and de-greasing cleaning operations, fuel tank
drain down and removal, and other activities which may result in discharge or spillage
of pollutants to the ground or into surface water runoff must be conducted using spill
prevention measures, such as drip pans. Contaminated surfaces shall be cleaned
immediately following any discharge or spill incident. Emergency repairs may be
performed on-site using temporary plastic placed beneath and, if raining, over the
vehicle.
Application of agricultural chemicals including fertilizers and pesticides shall be
conducted in a manner and at application rates that will not result in loss of chemical to
surface water runoff. Manufacturers’ recommendations for application rates and
procedures shall be followed.
All applicable BMPs shall be used to prevent or treat contamination of surface water
runoff by pH modifying sources. These sources include bulk cement, cement kiln dust,
fly ash, new concrete washing and curing waters, waste streams generated from
8
concrete grinding and sawing, exposed aggregate processes, and concrete pumping
and mixer washout waters. Some applicable BMPs from the DOE Manual include
Concrete Handling (BMP C151), Sawcutting and Surfacing Pollution Prevention (BMP
C152), and other Volume IV – Source Control BMPs.
It is important for any development to preserve the environmental elements within the
County, so the conservation of and protection of critical areas shall be adhered too.
There shall be no contamination of the groundwater as the project is in a well head
protection Zone II. All necessary steps must be taken to prevent contamination such as
following the requirements of this SWPPP document, due diligence and awareness by
the contractor and sub-contractors, and the utilization of all BMPs (construction and
source control) applicable to ensure protection of the County’s groundwater.
Any chemical treatment must be approved by the County.
Element #11: Protect Existing and Proposed Flow Control BMPs
Protection measures shall be applied/installed and maintained to prevent adverse
impacts to existing flow control BMPs and areas of proposed flow control BMPs for the
project. Adverse impacts can prompt the requirement to restore or replace affected
BMPs.
Element #12: Maintain BMPs
Protection measures shall be maintained to assure continued performance of their
intended function, to prevent adverse impacts to existing flow control BMPs and areas
of proposed flow control BMPs and protect other disturbed areas of the project.
Sediment control BMPs shall be inspected weekly or after a runoff-producing storm
event during the “Dry Season” and daily during the “Wet Season”. The inspection
frequency for stabilized, inactive sites shall be determined by the County based on the
level of soil stability and potential for adverse environmental impacts.
Temporary erosion and sediment control BMPs shall be removed on the approval of the
County inspector after final site stabilization is achieved or after the temporary BMPs
are no longer needed. Trapped sediment shall be removed or stabilized on site via
approved measures. Disturbed soil resulting from removal of BMPs or vegetation shall
be permanently stabilized.
Element #13: Manage the Project
Development projects shall be phased to prevent the transport of sediment from the
development site during construction, unless the project engineer can demonstrate that
construction phasing is infeasible. Re-vegetation of exposed areas and maintenance of
that vegetation shall be an integral part of the clearing activities for any phase.
9
Clearing and grading activities for developments shall be permitted only if conducted
pursuant to an approved site development plan (e.g., subdivision approval) that
establishes permitted areas of clearing, grading, cutting, and filling. When establishing
these permitted clearing and grading areas, consideration should be given to minimizing
removal of existing trees and minimizing disturbance and compaction of native soils
except as needed for building purposes. These permitted clearing and grading areas
and any other areas required to preserve critical or sensitive areas, buffers, native
growth protection easements, or tree retention areas as may be required by the
County, shall be delineated on the site plans and the development site.
Seasonal Work Limitations are from October 1 to April 30 where clearing, grading, and
other soil disturbing activities shall only be permitted if shown to the satisfaction of the
County that the transport of sediment from the construction site will be prevented.
Based on the information provided and local weather conditions, the County may
expand or restrict the seasonal limitation on site disturbance. The County may take
enforcement action (such as a notice of violation, administrative order, penalty, or stop-
work order) if violations are noticed, required BMPs are not be maintained or the
approved plans are not be followed. The following activities are exempt from the
seasonal clearing and grading limitations:
1. Routine maintenance and necessary repair of erosion and sediment control
BMPs;
2. Routine maintenance of public facilities or existing utility structures that do not
expose the soil or result in the removal of the vegetative cover to soil; and
3. Activities where there is one hundred percent infiltration of surface water runoff
within the site in approved and installed erosion and sediment control facilities.
All BMPs shall be inspected, maintained, and repaired as needed to assure continued
performance of their intended function. Additional BMPs and erosion control measures
shall be installed as deemed necessary to protect adjacent properties and County right-
of-ways.
Whenever inspection and/or monitoring reveals that the BMPs identified in the
Construction SWPPP are inadequate, due to the actual discharge of or potential to
discharge a significant amount of any pollutant, the SWPPP shall be modified, as
appropriate, in a timely manner.
Spillage and/or discharge of pollutants shall be reported within 24-hours.
Maintenance and repair of heavy equipment and vehicles involving oil changes,
hydraulic system drain down, solvent and de-greasing cleaning operations, fuel tank
drain down and removal, and other activities which may result in discharge or spillage
of pollutants to the ground or into surface water runoff must be conducted using spill
prevention measures, such as drip pans. Contaminated surfaces shall be cleaned
immediately following any discharge or spill incident. Emergency repairs may be
10
performed on-site using temporary plastic placed beneath and, if raining, over the
vehicle.
The Construction SWPPP shall be retained on-site or within reasonable access to the
site. The Construction SWPPP shall be modified whenever there is a significant change
in the design, construction, operation, or maintenance of any BMP. The County
Inspector shall be notified of any changes to the Construction SWPPP. The inspector
may require a plan modification to go through the County review process.
1. CONSTRUCTION SEQUENCE
1. Hold a pre-construction meeting with the City and obtain required permits.
2. Field locate and verify all existing services and utilities within the project area.
See verification note on plan sheets. Field verify horizontal and vertical
locations of utilities and utility connections and provide information to project
engineer.
3. Establish clearing and grading limits.
4. Construct perimeter silt fences and other erosion control measures as needed.
5. Schedule clearing limits and erosion control inspections with the City.
6. Pothole all existing utilities within construction area.
7. Demolish and remove any existing structures, roads, and utilities.
8. Construct improvements per plan.
9. Stabilize all exposed soils.
10. Arrange final inspection with the City.
11. On-site siltation fence to remain until the site is stabilized to the approval of the
City Inspector.
12. Remove TESC measures when allowed by City Inspector.
2. CONSTRUCTION SCHEDULE
Construction is anticipated to begin when all necessary permits have been issued.
Construction will be done in a single phase.
11
3. FINANCIAL/OWNERSHIP RESPONSIBILITIES
Daniel Yu (Assa 2, Inc.)
1420 348th St.
Federal Way, 98003
4. RESPONSIBLE PARTY
A 24-hour responsible party shall be on-site or on-call at all times. This person shall be:
Name: _________________________________
Phone: ____________________________
APPENDIX A
Plan Exhibits
VICINITY MAP
NOT TO SCALE
SITE
DEMOLISH AND REMOVEEXISTING 6' CYCLONE FENCEPRESERVE AND PROTECTEXISTING ASPHALT PARKINGAREA AND EXTRUDED CURBPRESERVE AND PROTECTEXISTING ASPHALT PARKINGAREA AND EXTRUDED CURBDEMOLISH AND REMOVEASPHALT AND EXTRUDED CURBDEMOLISH AND REMOVEASPHALT, CURB GUTTERAND SIDEWALKTESC PLANCALL 811 AT LEAST 48HOURS BEFORE YOU DIGVERIFICATION NOTEALL EXISTING UTILITIES IN THE CONSTRUCTION AREA SHALL BEIDENTIFIED AND VERIFIED FOR DEPTH AND LOCATION PRIOR TO ANYCONSTRUCTION ACTIVITIES SO TO IDENTIFY ANY POTENTIAL CONFLICTSWITH PROPOSED CONSTRUCTION. CONTACT PROJECT ENGINEERIMMEDIATELY IF ANY CONFLICTS ARE IDENTIFIED.PRIOR TO ANY CONSTRUCTION ACTIVITIES, VERIFY EXISTINGTOPOGRAPHY IS CONSISTENT WITH WHAT IS SHOWN ON PLANS AND IFTHERE ARE ANY POTENTIAL CONFLICTS WITH PROPOSED CONSTRUCTIONACTIVITIES. CONTACT PROJECT ENGINEER IMMEDIATELY IF ANYCONFLICTS ARE IDENTIFIED.1 INCH = 20 FEET (22"x34")GRAPHIC SCALE402001 INCH = 40 FEET (11"x17")CONSTRUCTION SEQUENCE1.HOLD A PRE-CONSTRUCTION MEETING WITH THE CITY AND OBTAINREQUIRED PERMITS.2.FIELD LOCATE AND VERIFY ALL EXISTING SERVICES AND UTILITIESWITHIN THE PROJECT AREA. SEE VERIFICATION NOTE ON PLANSHEETS. FIELD VERIFY HORIZONTAL AND VERTICAL LOCATIONS OFUTILITIES AND UTILITY CONNECTIONS AND PROVIDE INFORMATION TOPROJECT ENGINEER.3.ESTABLISH CLEARING AND GRADING LIMITS.4.CONSTRUCT PERIMETER SILT FENCES AND OTHER EROSION CONTROLMEASURES AS NEEDED.5.SCHEDULE CLEARING LIMITS AND EROSION CONTROL INSPECTIONSWITH THE CITY.6.POTHOLE ALL EXISTING UTILITIES WITHIN CONSTRUCTION AREA.7.DEMOLISH AND REMOVE EXISTING STRUCTURES, ROADS, ANDUTILITIES.8.CONSTRUCT IMPROVEMENTS PER PLANS.9.STABILIZE ALL EXPOSED SOILS.10.ARRANGE FINAL INSPECTION WITH THE CITY.11.ON-SITE SILTATION FENCE TO REMAIN UNTIL THE SITE IS STABILIZEDTO THE APPROVAL OF THE CITY INSPECTOR.12.REMOVE TESC MEASURES WHEN ALLOWED BY THE CITY INSPECTOR.INLET PROTECTION NOTEINLET PROTECTION SHALL BE INSTALLED IN ALLEXISTING INLETS DOWNSTREAM AND WITHIN500-FT OF SITE DISTURBED AREAS, AND IN ALL NEWINLETS BOTH ON-SITE AND OFF-SITETESC LEGENDINLET PROTECTIONSEE DETAIL 2, SHEET C4CLEARING LIMITS (0.18 AC)PRESERVE AND PROTECTAS NOTEDCONSTRUCTION ENTRANCESEE DETAIL 1, SHEET C4DEMOLISH AND REMOVE ASNOTED. MAY REQUIRESEPARATE PERMITFILTER FABRIC FENCESEE DETAIL 3, SHEET C4PRESERVE AND PROTECT ASNOTED1.THE FOLLOWING SEED MIXTURE SHALL BE AS BELOW AND SHALL BEAPPLIED AT THE RATE RECOMMENDED BY THE SUPPLIER2.SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIREIRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO FOSTER ANDPROTECT THE ROOT STRUCTURE.3.FOR SEED BEDS PLANTED BETWEEN OCTOBER 31 AND APRIL 30, ARMORINGOF THE SEED BED WILL BE NECESSARY. (E.G., GEOTEXTILES, JUTE MAT,CLEAR PLASTIC COVERING).4.BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL MEASURESSUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES, SWALES, LEVELSPREADERS AND SEDIMENT BASINS.5.THE SEEDBED SHALL BE FIRM WITH A FAIRLY FINE SURFACE, FOLLOWINGSURFACE ROUGHENING. PERFORM ALL OPERATIONS ACROSS OR AT RIGHTANGLES TO THE SLOPE.6.FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIER'SRECOMMENDATIONS. AMOUNTS USED SHOULD BE MINIMIZED, ESPECIALLYADJACENT TO WATER BODIES AND WETLANDS.7.THE CONTRACTOR WILL CHECK ALL SEEDED OR SODDED AREAS REGULARLYTO ENSURE THAT THE VEGETATIVE IS BEING ADEQUATELY ESTABLISHED.AREAS WILL BE REPAIRED, RESEEDED, AND FERTILIZED AS REQUIRED.SEEDING NOTESChewings or annual blue grass (Festucarubra var. commutata or Poa anna)Perennial rye (Lolium perenne)Redtop or colonial bentgrass (Agrostisalba or Agrostis tenuis)White dutch clover (Trifolium repens)TABLE 3.2. TEMPORARY EROSION CONTROL SEED MIX% Purity% Germination4050559892989890908590% WeightSOIL AMENDMENT NOTEALL DISTURBED SOILS SHALL BE AMENDED PERSOIL AMENDMENT NOTE ON SHEET C4.DEMOLITION NOTEBUILDING DEMOLITION COMPLETED UNDERSEPARATE PERMIT.APPROVEDPERMIT NO. XX-XXXXXX-XXDATENOTE:THIS APPROVAL IS VOID 1 (ONE) YEAR AFTERAPPROVAL DATE. THE CITY WILL NOT BE RESPONSIBLEFOR ERRORS AND/OR OMISSIONS ON THESE PLANS.FIELD CONDITIONS MAY DICTATE CHANGES TO THESEPLANS AS DETERMINED BY THE CITY ENGINEER.DESCRIPTIONREVISION DATE BY
CONTACT:
SHEET TITLE:
CLIENT:REV.WMRTSDESIGNER:ENGINEER:DRAWN:DATE:REVISED:PROJECT:DWG NAME:SHEETOFPhone: 253-857-5454 ~ Fax: 253-509-0044 ~ info@contourpllc.com
Mailing Address: P.O. Box 949, Gig Harbor, WA 98335
Physical Address: 4706 97th Street NW, Suite 100, Gig Harbor, WA 98332
CIVIL ENGINEERS ~ SURVEYORS ~ LAND PLANNERS
DANIEL YU (ASSA 2, INC.)
1420 348TH ST.
FEDERAL WAY, 98003
DANIEL YU PHONE:(206) 909-3788 ASSA 2 RETAIL BUILDINGA PORTION OF THE NE 1/4 OF THE SE 1/4 OF SECTION 20, TOWNSHIP 21 N, RANGE 4 E, W.M.,FEDERAL WAY, WASHINGTONJ. BARRB. ALLENJ. BARR2021 N04 E06.29.202323-01523-015-SITE DEV706.29.20233C3
TESC DETAILS SILT FENCE NOTES1.THE CONTRACTOR SHALL INSTALL AND MAINTAIN TEMPORARY SILT FENCES AT THE LOCATIONS SHOWN IN THEPLANS.2.CONSTRUCT SILT FENCES IN AREAS OF CLEARING, GRADING, OR DRAINAGE PRIOR TO STARTING THOSEACTIVITIES.3.THE SILT FENCE SHALL HAVE A 2 FEET MIN. AND 2.5 FEET MAX. HEIGHT ABOVE THE ORIGINAL GROUND SURFACE.4.THE FILTER FABRIC SHALL BE SEWN TOGETHER AT THE POINT OF MANUFACTURE TO FORM FILTER FABRICLENGTHS AS REQUIRED. LOCATE ALL SEWN SEAMS AT SUPPORT POSTS. ALTERNATIVELY, TWO SECTIONS OF SILTFENCE CAN BE OVERLAPPED, PROVIDED THE CONTRACTOR CAN DEMONSTRATE, TO THE SATISFACTION OF THEENGINEER, THAT THE OVERLAP IS LONG ENOUGH AND THAT THE ADJACENT FENCE SECTIONS ARE CLOSE ENOUGHTOGETHER 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 INACCORDANCE WITH THE MANUFACTURER'S RECOMMENDATIONS. ATTACH THE FILTER FABRIC TO THE POSTS IN AMANNER THAT REDUCES THE POTENTIAL FOR TEARING.6.SUPPORT THE FILTER FABRIC WITH WIRE OR PLASTIC MESH, DEPENDENT ON THE PROPERTIES OF THEGEOTEXTILE SELECTED FOR USE. IF WIRE OR PLASTIC MESH IS USED, FASTEN THE MESH SECURELY TO THEUP-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 APREFABRICATED POLYMERIC MESH. THE STRENGTH OF THE WIRE OR POLYMERIC MESH SHALL BE EQUIVALENT TOOR GREATER THAN 180 POUNDS GRAB TENSILE STRENGTH. THE POLYMERIC MESH MUST BE AS RESISTANT TOTHE SAME LEVEL OF ULTRAVIOLET RADIATION AS THE FILTER FABRIC IT SUPPORTS.8.BURY THE BOTTOM OF THE FILTER FABRIC 8 INCHES MIN. BELOW THE GROUND9.SURFACE. BACKFILL AND TAMP SOIL IN PLACE OVER THE BURIED PORTION OF THE FILTER FABRIC, SO THAT NOFLOW CAN PASS BENEATH THE FENCE AND SCOURING CANNOT OCCUR. THE WIRE OR POLYMERIC MESH SHALLEXTEND INTO THE GROUND 3 INCHES MIN.10.DRIVE OR PLACE THE FENCE POSTS INTO THE GROUND 18 INCHES MINIMUM. A 12-INCH MINIMUM DEPTH ISALLOWED 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:1V OR STEEPERAND THE SLOPE IS PERPENDICULAR TO THE FENCE. IF REQUIRED POST DEPTHS CANNOT BE OBTAINED, THEPOSTS SHALL BE ADEQUATELY SECURED BY BRACING OR GUYING TO PREVENT OVERTURNING OF THE FENCE DUETO SEDIMENT LOADING.11.USE WOOD, STEEL, OR EQUIVALENT POSTS. THE SPACING OF THE SUPPORT POSTS SHALL BE A MAXIMUM OF 6FEET. POSTS SHALL CONSIST OF EITHER:− 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.− NO. 6 STEEL REINFORCEMENT BAR OR LARGER.− ASTM A 120 STEEL PIPE WITH A MINIMUM DIAMETER OF 1 INCH.− U, T, L, OR C SHAPE STEEL POSTS WITH A MINIMUM WEIGHT OF 1.35 POUNDS/FEET.− OTHER STEEL POSTS HAVING EQUIVALENT STRENGTH AND BENDING RESISTANCE TO THE POST SIZES LISTED ABOVE.12.LOCATE SILT FENCES ON CONTOUR AS MUCH AS POSSIBLE, EXCEPT AT THE ENDS OF THE FENCE, WHERE THEFENCE SHALL BE TURNED UPHILL SUCH THAT THE SILT FENCE CAPTURES THE RUNOFF WATER AND PREVENTSWATER FROM FLOWING AROUND THE END OF THE FENCE.13.IF THE FENCE MUST CROSS CONTOURS, WITH THE EXCEPTION OF THE ENDS OF THE FENCE, PLACE GRAVELCHECK DAMS PERPENDICULAR TO THE BACK OF THE FENCE TO MINIMIZE CONCENTRATED FLOW AND EROSION.THE SLOPE OF THE FENCE LINE WHERE CONTOURS MUST BE CROSSED SHALL NOT BE STEEPER THAN 3H:1V.− 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.− 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.SILT FENCE INSTALLATION USING THE SLICING METHOD SPECIFICATION DETAILS FOLLOW:1.THE BASE OF BOTH END POSTS MUST BE AT LEAST 2 TO 4 INCHES ABOVE THE TOP OF THE FILTER FABRIC ONTHE MIDDLE POSTS FOR DITCH CHECK DAMS TO DRAIN PROPERLY. USE A HAND LEVEL OR STRING LEVEL, IFNECESSARY, TO MARK BASE POINTS BEFORE INSTALLATION.2.INSTALL POSTS 3 TO 4 FEET APART IN CRITICAL RETENTION AREAS AND 6 TO 7 FEET APART IN STANDARDAPPLICATIONS. INSTALL POSTS 24 INCHES DEEP ON THE DOWNSTREAM SIDE OF THE SILT FENCE, AND AS CLOSEAS POSSIBLE TO THE FILTER FABRIC, ENABLING POSTS TO SUPPORT THE FILTER FABRIC FROM UPSTREAM WATERPRESSURE.3.INSTALL POSTS WITH THE NIPPLES FACING AWAY FROM THE FILTER FABRIC.4.ATTACH THE FILTER FABRIC TO EACH POST WITH THREE TIES, ALL SPACED WITHIN THE TOP 8 INCHES OF THEFILTER FABRIC. ATTACH EACH TIE DIAGONALLY 45 DEGREES THROUGH THE FILTER FABRIC, WITH EACHPUNCTURE AT LEAST 1 INCH VERTICALLY APART. EACH TIE SHOULD BE POSITIONED TO HANG ON A POST NIPPLEWHEN TIGHTENING TO PREVENT SAGGING.5.WRAP APPROXIMATELY 6 INCHES OF FABRIC AROUND THE END POSTS AND SECURE WITH THREE TIES.6.NO MORE THAN 24 INCHES OF A 36-INCH FILTER FABRIC IS ALLOWED ABOVE GROUND LEVEL, 12 INCHES MUST BEBURIED.7.COMPACT THE SOIL IMMEDIATELY NEXT TO THE FILTER FABRIC WITH THE FRONT WHEEL OF THE TRACTOR, SKIDSTEER, OR ROLLER EXERTING AT LEAST 60 POUNDS PER SQUARE INCH. COMPACT THE UPSTREAM SIDE FIRSTAND THEN EACH SIDE TWICE FOR A TOTAL OF FOUR TRIPS. CHECK AND CORRECT THE SILT FENCE INSTALLATIONFOR ANY DEVIATION BEFORE COMPACTION. USE A FLAT-BLADED SHOVEL TO TUCK FABRIC DEEPER INTO THEGROUND IF NECESSARY.PLASTIC COVERING NOTESPLASTIC SLOPE COVER MUST BE INSTALLED AS FOLLOWS:1.RUN PLASTIC UP AND DOWN SLOPE, NOT ACROSS SLOPE.·PLASTIC MAY BE INSTALLED PERPENDICULAR TO A SLOPE IF THE SLOPE LENGTH ISLESS THAN 10 FEET.·MINIMUM OF 8-INCH OVERLAP AT SEAMS.·ON LONG OR WIDE SLOPES, OR SLOPES SUBJECT TO WIND, TAPE ALL SEAMS.·PLACE PLASTIC INTO A SMALL (12-INCH WIDE BY 6-INCH DEEP) SLOT TRENCH ATTHE TOP OF THE SLOPE AND BACKFILL WITH SOIL TO KEEP WATER FROMFLOWING UNDERNEATH.·PLACE SAND FILLED BURLAP OR GEOTEXTILE BAGS EVERY 3 TO 6 FEET ALONGSEAMS AND TIE THEM TOGETHER WITH TWINE TO HOLD THEM IN PLACE.·INSPECT PLASTIC FOR RIPS, TEARS, AND OPEN SEAMS REGULARLY AND REPAIRIMMEDIATELY. THIS PREVENTS HIGH VELOCITY RUNOFF FROM CONTACTING BARESOIL WHICH CAUSES EXTREME EROSION.·SANDBAGS MAY BE LOWERED INTO PLACE TIED TO ROPES. HOWEVER, ALLSANDBAGS MUST BE STAKED IN PLACE.2.PLASTIC SHEETING SHALL HAVE A MINIMUM THICKNESS OF 6 MIL.3.IF EROSION AT THE TOE OF A SLOPE IS LIKELY, A GRAVEL BERM, RIPRAP, OR OTHERSUITABLE PROTECTION SHALL BE INSTALLED AT THE TOE OF THE SLOPE IN ORDERTO REDUCE THE VELOCITY OF RUNOFF.GRADING AND TESC NOTES1.ALL REQUIRED SEDIMENTATION AND EROSION CONTROL FACILITIES MUST BE CONSTRUCTED AND IN OPERATIONPRIOR TO ANY LAND CLEARING AND/OR OTHER CONSTRUCTION TO ENSURE THAT SEDIMENT LADEN WATER DOESNOT ENTER ANY EXISTING DRAINAGE SYSTEM. THE CONTRACTOR SHALL SCHEDULE AN INSPECTION OF THE EROSIONCONTROL FACILITIES PRIOR TO ANY LAND CLEARING AND/OR OTHER CONSTRUCTION. ALL EROSION AND SEDIMENTFACILITIES SHALL BE MAINTAINED IN A SATISFACTORY CONDITION AS DETERMINED BY THE CITY, UNTIL SUCH TIMETHAT CLEARING AND/OR CONSTRUCTION IS COMPLETED AND THE POTENTIAL FOR ON-SITE EROSION HAS PASSED.THE IMPLEMENTATION, MAINTENANCE, REPLACEMENT, AND ADDITIONS TO THE EROSION AND SEDIMENTATIONCONTROL SYSTEMS SHALL BE THE RESPONSIBILITY OF THE PERMITTEE.2.THE EROSION AND SEDIMENTATION CONTROL SYSTEM FACILITIES DEPICTED ON THESE PLANS ARE INTENDED TO BEMINIMUM REQUIREMENTS TO MEET ANTICIPATED SITE CONDITIONS. AS CONSTRUCTION PROGRESSES ANDUNEXPECTED OR SEASONAL CONDITIONS DICTATE, FACILITIES WILL BE NECESSARY TO ENSURE COMPLETESILTATION CONTROL ON THE SITE. DURING THE COURSE OF CONSTRUCTION, IT SHALL BE THE OBLIGATION ANDRESPONSIBILITY OF THE PERMITTEE TO ADDRESS ANY NEW CONDITIONS THAT MAY BE CREATED BY HIS ACTIVITIESAND TO PROVIDE ADDITIONAL FACILITIES, OVER AND ABOVE THE MINIMUM REQUIREMENTS, AS MAY BE NEEDED TOPROTECT ADJACENT PROPERTIES, SENSITIVE AREAS, NATURAL WATER COURSES, AND/OR STORM DRAINAGESYSTEMS.3.NO TEMPORARY OR PERMANENT STOCKPILING OF MATERIALS OR EQUIPMENT SHALL OCCUR WITHIN CRITICAL AREASOR ASSOCIATED BUFFERS, OR THE CRITICAL ROOT ZONE FOR VEGETATION PROPOSED FOR RETENTION.CONSTRUCTION ENTRANCE NOTES1.MATERIAL SHALL BE 4" TO 8" QUARRY SPALLS ( 4 TO 6 INCH FOR RESIDENTIAL SINGLE FAMILY LOTS) AND MAYBE TOP-DRESSED WITH 1 TO 3 INCH ROCK.2.THE ROCK PAD SHALL BE AT LEAST 12" THICK AND 100' LONG (REDUCED TO 20 FEET FOR SITES LESS THAN 1ACRE OF DISTURBED SOIL) WIDTH SHALL BE FULL WIDTH OF INGRESS AND EGRESS AREA. SMALLER PADS MAYBE APPROVED FOR SINGLE-FAMILY RESIDENTIAL AND COMMERCIAL SITES .3.ADDITIONAL ROCK SHALL BE ADDED PERIODICALLY TO MAINTAIN FUNCTION OF THE PAD.4.IF THE PAD DOES NOT ADEQUATELY REMOVE MUD FROM THE VEHICLE WHEELS, THE WHEELS SHALL BE HOSEDOFF BEFORE THE VEHICLE ENTERS A PAVED STREET.THE WASHING SHALL BE DONE ON AN AREA COVEREDWITH CRUSHED ROCK AND WASH WATER SHALL DRAIN TO A SEDIMENT RETENTION FACILITY OR THROUGH ASILT FENCE PER WSDOT SPECIFICATION 9-33 CONSTRUCTION GEOTEXTILES.5.CRUSHED CONCRETE, CEMENT OR CALCIUM CHLORIDE FOR CONSTRUCTION ENTRANCE STABILIZATION IS NOTALLOWED.6.A SEPARATION GEOTEXTILE SHALL BE PLACED UNDER THE SPALLS TO PREVENT FINE SEDIMENT FROM PUMPINGUP INTO THE ROCK PAD. THE GEOTEXTILE SHALL MEET THE FOLLOWING STANDARDS:- GRAB TENSILE STRENGTH (ASTM D4751): 200 PSI MINIMUM- GRAB TENSILE ELONGATION (ASTM D4632): 30 PERCENT MAXIMUM- MULLEN BURST STRENGTH (ASTM D3786-80A): 400 PSI MINIMUM- AOS (ASTM D4751): 20 TO 45 (U.S. STANDARD SIEVE SIZE).1.ON-SITE EROSION CONTROL MEASURES SHALL BE THE RESPONSIBILITY OF THE DEVELOPER. ANYPROBLEMS OCCURRING BEFORE FINAL ACCEPTANCE OF THE STORM SYSTEM BY THE MUNICIPALITYSHALL BE CORRECTED BY THE APPLICANT AND/OR THE CONTRACTOR.2.IN CASE EROSION OR SEDIMENTATION OCCURS TO ADJACENT PROPERTY, ALL CONSTRUCTION WORKWITHIN THE DEVELOPMENT THAT WILL AGGRAVATE THE SITUATION MUST CEASE AND THEAPPLICANT/CONTRACTOR SHALL IMMEDIATELY COMMENCE RESTORATION OR MITIGATION MEASURES.RESTORATION ACTIVITY SHALL CONTINUE UNTIL SUCH TIME AS THE PROBLEM IS RECTIFIED.3.ALL EROSION AND SEDIMENTATION CONTROL DEVICES SHOWN ON THIS DRAWING SHALL BEINSTALLED PRIOR TO OR AS THE FIRST STAGE OF SITE PREPARATION.4.SHOULD THE TEMPORARY EROSION AND SEDIMENTATION CONTROL MEASURES AS SHOWN ON THISDRAWING NOT PROVE ADEQUATE TO CONTROL EROSION AND SEDIMENTATION, THEAPPLICANT/CONTRACTOR SHALL INSTALL ADDITIONAL FACILITIES AS NECESSARY TO PROTECTADJACENT PROPERTIES, SENSITIVE AREAS, NATURAL WATER COURSES, AND/OR STORM DRAINAGESYSTEMS.5.IN ANY AREA WHICH HAS BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND DISTURBINGACTIVITIES AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A PERIOD EXCEEDING THE LISTEDCRITERIA, ALL DISTURBED AREAS MUST BE IMMEDIATELY STABILIZED WITH MULCHING, GRASSPLANTING, OR OTHER APPROVED EROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR INQUESTION. GRASS SEEDING ALONE WILL BE ACCEPTABLE ONLY DURING THE MONTHS OF APRILTHROUGH SEPTEMBER, INCLUSIVE. SEEDING MAY PROCEED, HOWEVER, WHENEVER IT IS IN THEINTEREST OF THE APPLICANT/CONTRACTOR, BUT MUST BE AUGMENTED WITH MULCHING, NETTING, OROTHER TREATMENT. CRITERIA FOR EXPOSURE OF DISTURBED SURFACES FROM CHAPTER 8 OF THEPIERCE COUNTY STORMWATER MANAGEMENT MANUAL SHALL BE LISTED HERE BY THE ENGINEER.6.THE PROJECT ENGINEER OR PROJECT SURVEYOR WILL BE RESPONSIBLE FOR FIELD LOCATING THECLEARING LIMITS AND ESTABLISHING THOSE BOUNDARIES WITH BRIGHT COLORED FLAGGING. THECONTRACTOR SHALL CLEAR TO THE LIMITS AS ESTABLISHED ON THIS PLAN AND AS FLAGGED IN THEFIELD.7.THE CITY SHALL BE RESPONSIBLE FOR THE INSPECTION AND ACCEPTANCE OF ALL CLEARING ANDGRADING WORK AND EROSION AND SEDIMENTATION CONTROL FACILITIES. THE APPLICANT AND/ORCONTRACTOR SHALL NOTIFY THE CITY FORTY-EIGHT HOURS IN ADVANCE OF EACH REQUIRED EROSIONAND SEDIMENT CONTROL INSPECTION.INSPECTION NO. 1 - INSTALLATION OF EROSION CONTROL FACILITIES/PRIOR TO CLEARING.INSPECTION NO. 2 - COMPLETION OF CLEARING.INSPECTION NO. 3 - UPON COMPLETION OF EXCAVATION, FILLING, AND EARTHWORK.INSPECTION NO. 4 - COMPLETION OF PROJECT.INSPECTION NO. 5 - AS NEEDED TO DETERMINE COMPLIANCE WITH APPROVED PLANS AND/ORSPECIFICATIONS. (DOES NOT REQUIRE ADVANCE NOTICE.)8.ALL WORK ASSOCIATED WITH STABILIZING THE DISTURBED AREAS SHALL BE IN ACCORDANCE WITHTHE KING COUNTY STORMWATER MANAGEMENT MANUAL.9.ALL NECESSARY FACILITIES SHALL BE MAINTAINED ON SITE TO PREVENT DEBRIS, DUST, AND MUDFROMACCUMULATING ON THE PUBLIC RIGHT-OF-WAY.10.CONTRACTOR SHALL LEAVE THE INFILTRATION SYSTEM OFFLINE (DOES NOT RECEIVE STORMWATER)UNTIL THE SITE IS SUBSTANTIALLY STABILIZED OR AT THE APPROVAL OF THE ENGINEER. UNDER NOCIRCUMSTANCES IS CONCRETE WASH OUT WATER OR HEAVY SEDIMENTS TO BE ALLOWED IN STORMSYSTEM.STANDARD EROSION CONTROL NOTESNOT TO SCALECONSTRUCTION ENTRANCE1NOT TO SCALESILT FENCE DETAIL3NOTE: IF TO BE USED AS HIGH VISIBILIY FENCE,IT SHALL BE 4 FT. MIN. HIGH FROM SURFACEGRADE AND MUST BE HIGHLY VISIBLE.NOT TO SCALEINLET PROTECTION DETAIL2OVERFLOW BYPASS5" MAX.TRIMGRATE FRAMEFILTEREDWATERSEDIMENT AND DEBRIS(PROVIDE 5 CF OF STORAGE)DRAINAGE GRATEBELOW INLET GRATE DEVICEOVERFLOW BYPASS (TYP.)DRAINAGE GRATE~ RECTANGULAR GRATE SHOWNRETRIEVAL SYSTEM (TYP.)BELOW INLET GRATE DEVICEINLET PROTECTION NOTES1.FILTERS SHALL BE INSPECTED AFTER EACH STORM EVENT AND CLEANED ORREPLACED WHEN 1/3 FULL.2.ALL CATCH BASINS WITHIN 500' DOWNSLOPE OF PROJECT SITE SHALL INSTALLINLET PROTECTION, AS WELL AS ANY OTHER CATCH BASINS THAT COULDPOSSIBLE RECEIVE RUNOFF FROM THE CONSTRUCTION SITE SHALL HAVE INLETPROTECTION INSTALLED AND MAINTAINEDAMENDED SOILS NOTE·SOIL AMENDMENTS ARE REQUIRED FOR ALL DISTURBED AREAS IN ACCORDANCE WITH BMP L613:POST-CONSTRUCTION SOIL QUALITY AND DEPTH OF THE 2012 SURFACE WATER MANAGEMENTMANUAL·AMENDED SOILS SHALL BE A MINIMUM OF 8" (NON-COMPACTED) WITH SUBSOILS SCARIFIED ATLEAST 4" WITH INCORPORATION OF THE UPPER MATERIAL TO AVOID STRATIFIED LAYERS, WHEREFEASIBLE.·QUALITY OF COMPOST AND OTHER MATERIALS USED TO MEET THE ORGANIC CONTENTREQUIREMENTS ARE AS FOLLOWS:A.THE ORGANIC CONTENT FOR “PRE-APPROVED” AMENDMENT RATES CAN BE MET ONLY USINGCOMPOST THAT MEETS THE DEFINITION OF “COMPOSTED MATERIALS” IN WAC 173-350-220.THE WAC IS AVAILABLE ONLINE AT:HTTP://WWW.ECY.WA.GOV/PROGRAMS/SWFA/FACILITIES/350.HTML THE COMPOST MUST ALSOHAVE AN ORGANIC MATTER CONTENT OF 35% TO 65%, AND A CARBON TO NITROGEN RATIOBELOW 25:1. THE CARBON TO NITROGEN RATIO MAY BE AS HIGH AS 35:1 FOR PLANTINGSCOMPOSED ENTIRELY OF PLANTS NATIVE TO THE PUGET SOUND LOWLANDS REGION.B.CALCULATED AMENDMENT RATES MAY BE MET THROUGH USE OF COMPOSTED MATERIALS ASDEFINED ABOVE; OR OTHER ORGANIC MATERIALS AMENDED TO MEET THE CARBON TONITROGEN RATIO REQUIREMENTS, AND MEETING THE CONTAMINANT STANDARDS OF GRADEA COMPOST.·USE ONE OF THE FOLLOWING OPTIONS TO MEET THE POST CONSTRUCTION SOIL QUALITY ANDDEPTH REQUIREMENTS. USE THE MOST RECENT VERSION OF "GUIDELINES FOR RESOURCES FORIMPLEMENTING SOIL QUALITY AND DEPTH BMP T5.13" TO MEET THE REQUIREMENTS OF THIS BMP.THIS GUIDANCE CAN BE FOUND ONLINE AT: WWW.SOILSFORSALMON.ORGA.LEAVE NATIVE VEGETATION AND SOIL UNDISTURBED, AND PROTECT FROM COMPACTIONDURING CONSTRUCTIONB.AMEND EXISTING SITE TOPSOIL OR SUBSOIL EITHER AT DEFAULT "PRE-APPROVED" RATES, ORAT CUSTOM CALCULATED RATES BASED ON SPECIFIERS TESTS OF THE SOIL AND AMENDMENTC.STOCKPILE EXISTING TOPSOIL DURING GRADING, AND REPLACE IT PRIOR TO PLANTING.STOCKPILED TOPSOIL MUST ALSO BE AMENDED IF NEEDED TO MEET THE ORGANIC MATTEROR DEPTH REQUIREMENTS, EITHER AT A DEFAULT "PRE-APPROVED" RATE OR AT A CUSTOMCALCULATED RATE.D.IMPORT TOPSOIL MIX OF SUFFICIENT ORGANIC CONTENT AND DEPTH TO MEET THEREQUIREMENTS. MORE THAN ONE METHOD MAY BE USED ON DIFFERENT PORTIONS OF THESAME SITE. SOIL THAT ALREADY MEETS THE DEPTH AND ORGANIC MATTER QUALITYSTANDARDS, AND IS NOT COMPACTED, DOES NOT NEED TO BE AMENDED.·AMENDED SOILS SHALL BE MAINTAINED AS FOLLOWS:A.SOIL QUALITY AND DEPTH SHOULD BE ESTABLISHED TOWARD THE END OF CONSTRUCTIONAND ONCE ESTABLISHED, SHOULD BE PROTECTED FROM COMPACTION, SUCH AS FROM LARGEMACHINERY USE, AND FROM EROSION.B.SOIL SHOULD BE PLANTED AND MULCHED AFTER INSTALLATION.C.PLANT DEBRIS OR ITS EQUIVALENT SHOULD BE LEFT ON THE SOIL SURFACE TO REPLENISHORGANIC MATTER.D.IT SHOULD BE POSSIBLE TO REDUCE USE OF IRRIGATION, FERTILIZERS, HERBICIDES ANDPESTICIDES. THESE ACTIVITIES SHOULD BE ADJUSTED WHERE POSSIBLE, RATHER THANCONTINUING TO IMPLEMENT FORMERLY ESTABLISHED PRACTICES.SEE PROJECT CONSTRUCTION SWPPP FOR ADDITIONAL INFORMATION OR SECTION 2.2.1.4 OF CHAPTER2 OF VOLUME 6 OF THE 2016 CITY OF TACOMA SURFACE WATER MANAGEMENT MANUALCALL 811 AT LEAST 48HOURS BEFORE YOU DIGVERIFICATION NOTEALL EXISTING UTILITIES IN THE CONSTRUCTION AREA SHALL BEIDENTIFIED AND VERIFIED FOR DEPTH AND LOCATION PRIOR TO ANYCONSTRUCTION ACTIVITIES SO TO IDENTIFY ANY POTENTIAL CONFLICTSWITH PROPOSED CONSTRUCTION. CONTACT PROJECT ENGINEERIMMEDIATELY IF ANY CONFLICTS ARE IDENTIFIED.PRIOR TO ANY CONSTRUCTION ACTIVITIES, VERIFY EXISTINGTOPOGRAPHY IS CONSISTENT WITH WHAT IS SHOWN ON PLANS AND IFTHERE ARE ANY POTENTIAL CONFLICTS WITH PROPOSED CONSTRUCTIONACTIVITIES. CONTACT PROJECT ENGINEER IMMEDIATELY IF ANYCONFLICTS ARE IDENTIFIED.APPROVEDPERMIT NO. XX-XXXXXX-XXDATENOTE:THIS APPROVAL IS VOID 1 (ONE) YEAR AFTERAPPROVAL DATE. THE CITY WILL NOT BE RESPONSIBLEFOR ERRORS AND/OR OMISSIONS ON THESE PLANS.FIELD CONDITIONS MAY DICTATE CHANGES TO THESEPLANS AS DETERMINED BY THE CITY ENGINEER.DESCRIPTIONREVISION DATE BY
CONTACT:
SHEET TITLE:
CLIENT:REV.WMRTSDESIGNER:ENGINEER:DRAWN:DATE:REVISED:PROJECT:DWG NAME:SHEETOFPhone: 253-857-5454 ~ Fax: 253-509-0044 ~ info@contourpllc.com
Mailing Address: P.O. Box 949, Gig Harbor, WA 98335
Physical Address: 4706 97th Street NW, Suite 100, Gig Harbor, WA 98332
CIVIL ENGINEERS ~ SURVEYORS ~ LAND PLANNERS
DANIEL YU (ASSA 2, INC.)
1420 348TH ST.
FEDERAL WAY, 98003
DANIEL YU PHONE:(206) 909-3788 ASSA 2 RETAIL BUILDINGA PORTION OF THE NE 1/4 OF THE SE 1/4 OF SECTION 20, TOWNSHIP 21 N, RANGE 4 E, W.M.,FEDERAL WAY, WASHINGTONJ. BARRB. ALLENJ. BARR2021 N04 E06.29.202323-01523-015-SITE DEV706.29.20234C4
APPENDIX B
Applicable BMPs