15-10271725,E ry
Jim Ferrell, Mayor
July 1, 2015
Mr. Tony Douchette
City of Federal Way — PW/SWM
33325 8th Avenue South
Federal Way, WA 98003
FILE
Re: File #15-102717-00-AD; Pacifc Highway Dispersion Trench, South 356th
Dear Mr. Doucette:
The Community Development Department approves your request to install a stormwater dispersion trench
on a Surface Water Management (SWM) property located at 3580 Pacific Highway South. The trench is
associated with the SR 99 Phase V capital improvement project that will begin construction next year. As
provided in your memo, the trench will be located within a wetland buffer on the SWM property. The scope
of work includes two 50-foot long and 2.5-foot wide dispersion trenches that will be approximately 3-feet
deep and filled with gravel. The alignment will be adjusted during installation to avoid trees as much as
possible. Disturbed areas caused by construction will be seeded with a native seed mix.
DIRECTOR AUTHORIZATION
Recently passed Federal Way Ordinance #15-757 provides the Director of Community Development
authority to issue a partial exemption to environmentally critical areas regulations under interim code citation
Federal Way Revised Code (FWRC) 19.145.120(1) for essential public facilities, such as state transportation
facilities. The intrusion into the wetland buffer is the minimum necessary to mitigate stormwater impacts
from the Phase V capital project. Further, the SWM Division will mitigate construction impacts by avoiding
tree removal when possible and replanting the areas disturbed by the trench construction.
CLOSING
Please contact Senior Planner Matt Herrera at matt.herrera@.cityoffederal,,vay.com, or 253-825-2638 with any
questions regarding this authorization to proceed.
Sincerely,
Michael A. Morales
Director of Community Development
c: Matt Herrera, Senior Planner
Doc. I.D. 69915
33325 8th Avenue South, Federal Way, WA 98003-6325 o (253) 835-7000 • www.cityoffederalway.com
,fib 15-(oZ-7('-�
MEMORANDUM
Public Works
Jim Ferrell, Mayor
Date: June 2"d, 2015
To: Isaac Conlen, Planning Manager
From: Tony Doucette, P.E.
Subject: Pacific Highway Dispersion Trench South of S 3561h Street
Surface Water Management plans to install a dispersion trench on a SWM owned
conservation property south of S 356th Street and east of Pacific Highway as shown on
Exhibit 1. The dispersion trench will be installed in advance of improvements to Pacific
Highway with the Phase V HOV lanes to be constructed next year. The entire proposed
work is outside of the wetland buffer as mapped by City GIS data, however, the work is
within the wetland buffer delineated by a wetland report prepared with the S 356th at
Pacific Highway intersection improvements in 2005. The conservation property was
acquired with King County grant assistance and the proposed use has already been
approved by King County staff. This memorandum details the proposed installation plan,
requesting permission from the Director of Community Development per the City of
Federal Way Revised Code (FWRC) section 19.175.040-(3). The proposed facility and
areas of impact/restoration are discussed below.
Exhibit 1 shows the proposed trench location, the City's wetland GIS mapping and the
wetland mapping from the S 356th at Pacific Highway intersection improvements.
Exhibit 2 shows the trench and pipe alignments, profiles and details. Two 50-ft long
gravel trenches will be connected by +/-54 ft of 12-in diameter storm drain. Both
dispersion trenches will be 2.5 ft wide, approximately 3 ft deep and filled with gravel and
a notched board to evenly distribute flow. The alignment of the trenches as shown will
be adjusted during installation to avoid existing trees as much as possible, and the
disturbed limits for construction will be minimized. Small, tracked equipment will be
used to install the trench and disturbed areas outside of the trench widths will be seeded
with a native seed mix. The total disturbed area will be +/-1,500 sf, and installation will
involve +/- 50 yards of earthwork. The trenches will be installed by SWM maintenance
staff in July of this year and should require limited maintenance after installation.
+/- 15,000 sq ft of runoff that already drains to the conservation property via sheet flow
will be collected and treated by Filterra Units installed with the Phase V improvements
before entering the proposed dispersion trenches. Both trenches have more than 200 ft of
flow path prior to entering the wetland. Runoff will flow through the conservation
property and eventually to the culvert under S 359`" Street at the north fork of West
Hylebos Creek.
The proposed installation activity described in this memorandum is a one-time event.
Please do not hesitate to request additional information or clarification if needed.
Sincerely,
Tony Doucette, P.E.
SWM Engineer
Attachments:
1. Exhibit 1: Location Map
2. Exhibit 2: Dispersion Trench Design Drawings
3. S 356`h St 1 SR 99 Intersection Wetland Report
CUY OF
Federal Way
South 356th Street / SR 99 Intersection Improvement Project
Draft Wetland and Stream Delineation Technical Memorandum
Date: December 12, 2005 (Updated January, 2006)
To: Al Emter, City of Federal Way
From: HDR Engineering Inc.
Subject: Draft Wetland and Stream Delineation Technical Memorandum for the South
356th Street/SR 99 Intersection Improvements Project
Purpose of the memorandum
This memorandum documents the wetlands and streams found in a portion of the South
356th Street/SR 99 Intersection Improvements Project area. The study area consists of
the area east of Pacific Highway South (also known as State Route 99) and south of the
existing South 356th Street (Attachment 1). All of the study area is within the Hylebos
Creek drainage basin.
A two step process was used to determine the presence of wetlands and streams in the
study area. In step one, HDR staff reviewed existing environmental documents. The
second step was a field evaluation. The initial field reconnaissance was followed by
delineation of wetlands and streams within the study area. These steps and the results
are discussed in detail below.
Document Review
HDR Staff reviewed the following existing environmental documents to determine the
presumed presence of wetlands in the South 356th Street/SR 99 Intersection
Improvements Project study area:
• National Wetland Inventory Wetland Mapper
(http://wetlandsfws.er.usas.ciov/wtlnds/launch.html)
• King County Wetland Inventory
(htt://www.metrokc. ovl is/ma octal/iMAP main.htm)
• Soil Survey of King County Area, Washington (Snyder et al., 1973)
• City of Federal Way zoning and critical areas maps
(htip://www,cityoffederalway.com/Page.aspx?view=341)
• Friends of the Hylebos Wetlands website (http://www.hylebos.org/index.htm)
Wetlands
No wetlands were mapped on the proposed South 356th Street alignment. A single large
wetland (Wetland 32-21-4-119) is mapped to the south of the alignment and extending
over to SR 99 at 359th (see attachment 1).
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 35e Street / SR 99 Intersection Improvement Project Page 1
Streams
One stream (the headwaters of the North Fork Hylebos Creek) is mapped in the study
area. North Fork Hylebos Creek crosses the study area flowing east along South 356th
Street and then south out of the study area.
Zoning
The study area is zoned BP, for business park development (Attachment 1). Zoning for
surrounding areas includes business development and residential districts.
Land Use
The portion of the study area near the intersection of South 356th Street and SR 99 is
currently used for commercial purposes and the eastern half is vacant. Areas to the
south are entirely vacant, and are currently vegetated with a mixture of forested and
shrub wetland and forested upland communities.
The surrounding land uses include a mixture of vacant land and commercial and
residential developments (Attachment 2). A commercial tire recycling operation and a
large stormwater facility (operated by the City if Federal Way) are located to the north.
The parcel on Pacific Highway South (west of the Federal Way Parcel) immediately
south of the proposed South 3561" Street alignment is occupied by a motel.
Field Reconnaissance
Vegetation, soil, and hydrologic conditions were observed in several locations along the
proposed South 356" Street alignment. No wetlands were identified in the proposed
South 3561" Street alignment; however two wetlands were identified to the south and
east.
Vegetation in proposed south 356t" Street alignment is dominated by a mixture of
bentgrasses (Agrostis sp.) and disturbance tolerant forbs (hairy cat's ear [Hypocharis
radicata], plantain [Plantago sp.],) and small red alder (Alnus rubra) and black
cottonwood (Populus balsamifera) saplings (Photographs 1, 2, and 3).
The areas to the north and south of the alignment are forested. The forest canopy
dominated by red alder and black cottonwood with a few scattered western red cedar
(Thuja plicata). The understory is predominantly Himalayan blackberry (Rubus
armeniacus) with salmonberry (Rubus spectabilis), snowberry (Symphoricarpos albus),
redtwig dogwood (Corpus sericea), and Indian plum (Oemleria cerasiformis) locally
dominant. Reed canarygrass (Phalaris arundinacea), sword fern (Polystichum munitum)
and bracken fern (Pteridium aquilinum) are the dominant herbaceous species.
Some areas of shallow surface ponding (approximately 1 inch) were observed near the
proposed alignment, but this likely result from recent rainfall on the compacted surface.
No saturated soils were observed in this area. Soils in the forested area were loose and
well drained, with no indications of saturation or ponding.
No redoxymorphic features were observed in the soils along the proposed South 356t"
Street alignment (See data plot Beck-1-11). This slope to the south of the proposed
alignment show ample evidence of filling. Construction debris (large rocks, wood
material, and a street lamp base) was present on the surface, and the stem of a western
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 3561h Street / SR 99 Intersection Improvement Project Page 2
red cedar tree was partially buried by dirt and debris, subsequently killing the tree. An
old erosion control fence is located at the top of the bank. Both the fill and the fence
likely date to the time of the tank removal and cleanup.
Wetlands
HDR Staff visited the study area on November 29th and 30th, and December 9th, 2005
to confirm the location of wetland boundaries and stream ordinary high water marks.
Two wetlands were identified. Detailed descriptions of the wetlands are provided below,
and a summary of the characteristics of the wetlands identified in the field
reconnaissance is provided in Table 1. A description of the delineation methods is
provided in Appendix A. Note that the boundaries delineated by HDR biologists have
not been reviewed by regulatory agencies, and should be considered preliminary.
Table 1. Wetland Size, Rating, and Classification for Wetlands in the South 356th Street/
Pacific Highway South Intersection Improvements study area
Wetland Estimated Wetland Rating Buffer Widtha
Area City of Federal (in feet)
(in acres) Way'
USFWS
b
Classification
Wetland 32-21-4-119 80 acres° 1 200
Forested, Scrub/shrub,
_
Emergent
Wetland 2 -2,440 square Not Regulated -
Forested
feetd
a Wetland ratings and buffer widths are based on Federal Way Community Code, Chapter 22. All ratings shown in this table are
preliminary and have not been reviewed by the City of Federal Way or other regulatory agencies.
b Cowardin et al. (1979). All wetlands are palustrine.
° Overall wetland size is estimated based on aerial photograph interpretation and City of Federal Way wetland inventory
information.
d Wetland size is based on instrument survey by EMS Consulting, 2005.
Wetland 32-21-4-119
Descri firm
Wetland 32-21-4-119 occupies a broad flat area on either side of North Fork Hylebos
Creek Attachment 1 and Figure 1). Habitats present in Wetland 32-21-4-119 include
forested, scrub/shrub and emergent communities.
vegetation
The northern edge of Wetland 32-21-4-119 consists for forested wetland. The canopy is
dominated by red alder although occasional western red cedar trees are also present
(Photographs 4 and 5). A few scattered western hemlock (Tsuga heterophylla) trees are
present on hummocks, and black cottonwood is dominant in the south and west.
Salmonberry is the dominant shrub, although scattered hardhack (Spiraea douglasit)
shrubs are also present. Herbaceous vegetation is largely absent in the northern end of
Wetland 32-21-4-119, although reed canarygrass, stinging nettle (Urtica dioica), and
creeping buttercup (Ranunculus repens) were observed further away from the wetland
boundary (Photograph 7).
Vegetation in the southern portions of Wetland 32-21-4-119 is predominantly red alder
and black cottonwood, although occasional western red cedar. The understory includes
Sitka, pacific, and Scouler's willows (Salix Sitchensis, S. lasiandra var. lucida, and S.
scouleriana), vine maple (Acer circinatum), salmonberry and hardhack (Spiraea
douglasit). The herbaceous vegetation includes reed canarygrass, stinging nettle, lily -of -
the -valley (Maianthenum dilatatum), creeping buttercup, and skunk cabbage (Lysichiton
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way - S. 356rh Street / SR 99 Intersection Improvement Project Page 3
americanum). Several emergent areas are present in Wetland 32-21-4-119. Emergent
areas in the north are dominated by cree� ing buttercup and reed canarygrass, and the
emergent area along SR 99 north of 356' Street is predominantly reed canarygrass.
The dominant species in Wetland 32-21-4-119 are facultative or wetter, and their
presence satisfies the hydrophytic vegetation criterion.
The adjacent uplands to the north are dominated by disturbed upland forest, which slope
upward and west onto the motel parcel, and upward and north (Photographs 4 and 5).
Vegetation on these slopes is predominantly red alder and black cottonwood, although
big leaf maple (Acer macrophyllum) and western hemlock are also present. The
understory is dominated by dense thickets of Himalayan blackberry, but vine maple and
salmonberry are also present in substantial quantities. The herbaceous stratum is
predominantly stinging nettle, and mosses are common on the surface of the ground to
the north.
Adjacent upland along South 359th Street and Pacific Highway South include disturbed
upland forest and mowed road edges. The canopy of this forest is predominantly red
alder and black cottonwood, although Douglas fir and big leaf maple are also present.
The understory includes dense thickets of Himalayan blackberry, and more dispersed
Indian plum, red elderberry (Sambucus racemosa), hardhack, and Scouler's willow.
Occasional ornamental shrubs (apples [Malus domestica] and holly [llix aquifolium])
were also present. The herbaceous strata includes reed canarygrass, largeleaf avens
(Geum macrophyllum), cleavers bedstraw (Gallium aparine) and creeping buttercup.
Sword fern, bracken fern, and western St John's wort (Hypericum formosa) are locally
abundant.
Hydrolag
Elevated groundwater appears be the primary water source for the northern portion of
Wetland 32-21-4-119. Overflows from North Fork Hylebos Creek are channeled directly
under the proposed South 256th Street alignment to Wetland 32-21-4-119 in a concrete
culvert (Photographs 8-10), and likely also play an important role in the hydrology of the
system. Runoff from adjacent uplands may also contribute water to the wetland. Areas
of shallow inundation and soils saturated to the surface were observed in Wetland 32-
21-4-119 (Photographs 6 and 13). The presence of saturated soils in the upper 12
inches of the soil profile is indicative of wetland hydrology.
Adjacent upland areas are well drained. Soils were excavated to a depth of at least 17
inches, and no saturation was observed (Photographs 14 and 15).
Soils
Soils in the northern portion of Wetland 32-21-4-119 were composed of black (10YR 2/1)
silt loam extending to a depth of more than 16 inches (Photograph 13). In the southern
portion of the wetland, a narrower layer of this silt loam overlies a layer of gleyed,
greenish gray (5GY 6/1) clay to olive gray (5Y 5/2) clay loam with fine prominent
redoxymorphic features. The presence of this low chroma soil colors and redoxymorphic
features meets the wetland soil criterion.
Soils in the adjacent uplands were generally loam overlying fine sands to gravelly sandy
loam. Glass, PVC pipe and other construction debris were common on the (likely) filled
slopes to the north (Photographs 12 and 14). Soils to the west of Wetland 32-21-4-119
appear to be natural, and have some hydric characteristics before meeting the fill slopes
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 356�h Street / SR 99 Intersection Improvement Project Page 4
to the motel site. The owners of the motel site indicate that this area was substantially
wetter in the past.
Conclusion
All three wetland criteria (wetland vegetation, hydrology, and soils) were present in
Wetland 32-21-4-119. The presence of positive indicators for these three criteria meets
the wetland definition.
Wetland Rating
The City of Federal Way classifies Wetland 32-21-4-119 as a Category I wetland under
the Federal Way Community Code (FWCC 22) due to the size and number of wetland
communities. Category I wetlands require a standard buffer width of 200 feet. Our field
observations confirm the approximate location of the wetland as shown on Zoning Map
No. 98.
Wetland 2
Description
Wetland 2 is a small (approximately 2,440 square feet) forested wetland located
between Wetland 1 and Pacific Highway South (see Figure 1). It occupies a shallow
depression in the upland terrace east Wetland 1. Wetland 2 is not shown on the Federal
Way Wetland Inventory.
ye_ Qetatlon
Vegetation in Wetland 2 is dominated by red alder and black cottonwood, with an
understory of hardhack and salmonberry. The herbaceous stratum is dominated by
creeping buttercup and largeleaf avens, though some small pockets of slough sedge
(Carex obnupta) are present. The overall plant community is dominated by species
ranked as facultative or wetter, which satisfies the wetland vegetation criterion.
The surrounding uplands are dominated by similar species, but also include dense
thickets of Himalayan blackberry, along with reed canarygrass and cleavers bedstraw
(see Appendix A, data sheets 1 U and 21-1). Much of the area east of the pullout on
Pacific Highway South has been paved with asphalt in the past. The asphalt has
become covered with a thin layer of organic debris and herbaceous vegetation.
Hydrology
Wetland 2 appears to receive its water as runoff from the adjacent uplands. Saturated
soils were observed in the upper 12 inches of the soil profile during the delineation, but
the B and C horizons were not saturated. This may be the result of the relatively
impermeable strata trapping water at the surface. The presence of saturated soils in the
upper 12 inches of the soil profile meets the wetland hydrology criterion.
Soils
Soils in Wetland 2 consist of a very dark gray (10YR 3/1) silt loam overlying a dark
grayish brown (2.5Y 4/2) gravelly silt loam with many, large dark yellowish brown (10YR
4/6) redoxymorphic features. The presence of low chroma soil colors with
redoxymorphic features meets the wetland soil criterion.
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 35e Street / SR 99 Intersection Improvement Project Page 5
Conclusion
All three parameters (wetland vegetation, hydrology, and soils) were present in Wetland
2. This supports the conclusion that the area meets the definition of a wetland.
Wetland Rating
Wetland 2 is less than 2,500 square feet in size and has only one wetland habitat type.
Wetlands less than 2,500 square feet are not regulated by the City of Federal Way, and
do not have buffer requirements. It should be noted that the City may determine that
Wetland 2 is functionally connected to Wetland 1. If this is the case, Wetland 2 would be
regulated under Federal Way's community code, and would receive a rating and the
applicable buffer.
While activities in Wetland 2 would not be regulated by the City of Federal Way, the area
does meet the three parameter wetland definition, and is still subject to regulation by
state and federal agencies. The US Army Corps of Engineers regulates fill all wetlands
that are not isolated, and the Washington State Department of Ecology regulates
activities in all wetlands, regardless of whether they are isolated or not. Final
determination of whether a wetland is isolated or adjacent rests with the US Army Corps
of Engineers.
Streams
Three streams (North Fork Hylebos Creek and two unnamed tributaries) were identified
in the study area during the field investigation. A detailed description of the streams is
provided below, and a summary of stream characteristics is provided in Table 2.
Table 2. Rating and stream types for streams in the South 356th Street/ Pacific Highway
South Intersection Improvements study area
Stream Stream Ratinga Buffer width Washington State Department of
(in feet) Natural Resources Stream Type
North Fork Fish Bearing 100 F
Hylebos Creek
Tributary 1 Tributary to Fish 100 Np (Perennial stream, assumed to be
Bearing Stream non -fish bearing)
Tributary 2 Tributary to Fish 100 Np (Perennial stream, assumed to be
Bearing Stream non -fish bearing)
a Stream ratings and buffer widths are based on Federal Way Community Code, Chapter 22. All ratings shown in this table are
preliminary and have not been reviewed by the City of Federal Way or other regulatory agencies.
b Washington State Department of Natural Resources stream types are based on the Forest Practices Rule for (WAC 222-16-
031).
All stream rating and typing is preliminary and has not been reviewed by the City of Federal Way or other regulatory agencies.
Stream Description: North Fork Hylebos Creek
The North Fork Hylebos Creek is a perennial stream. While the City of Federal Way
maps for the area show a portion of the channel on the north side of South 356th Street,
no channel was observed in this area (Photographs 16 and 17). The former channel
may have been pied into a culvert and control structure (Photograph 18) on the north
side of South 356` Street. The stream crosses South 359th Street to the east of SR 99
and flows eastwards near the toe of slope for South 356th Street. Approximately 250
feet to the east, North Fork Hylebos Creek turns to flow south where it crosses the study
area. The stream continues to flow southwards, crossing under South 359th Street
approximately 1,000 feet west of SR 99.
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 356�h Street / SR 99 Intersection Improvement Project Page 6
North Fork Hylebos Creek crosses under South 3561h Street in a concrete culvert
(Photograph 19). The stream width at the Ordinary High water Mark (OHWM) varied
from 6 to 10 feet. A small, riprap lined channel (separated from the main channel by
more riprap) extends south approximately 50 feet to an 18 inch concrete culvert, which
carries the overflow southward to Wetland 32-21-4-119 (Photographs 8 to 10). Forest
vegetation (red alder, black cottonwood, Himalayan blackberry, snowberry, and
salmonberry) provides approximately 100 percent cover for the overflow channel.
The main stem of Norm Fork Hylebos Creek travels east along the south side of South
3561h Street. The channel in this reach varies from 6 to 10 feet wide at the Ordinary High
Water Mark (OHWM), and the banks are approximately 4 feet high and steeply sloped.
Riprap has been placed along the banks to stabilize the stream. A small ridge of dirt is
located immediately south of the stream, likely this material was excavated to create the
current stream channel. The substrate in this reach is largely fines, although some
riprap is also present in the channel. The stream is characterized by relatively fast
moving water with few riffles. Forest vegetation (as described above) provides
approximately 100 percent stream cover (Photographs 29 and 30). This riparian
vegetation is approximately 100 feet wide to the south and 20 feet wide to the north,
where the stream buffer meets South 3561h Street (Photograph 31).
Approximately 250 feet east of the culvert, North Fork Hylebos Creek turns to the south.
The OHWM in this reach varies from 3 to 8 feet in width, and the steep banks are
approximately 4 to 5 feet high. Riprap walls line portions of the eastern bank. The
substrate includes more gravel; small pools (approximately 5 feet long and 1 foot deep)
alternate with shallow riffles. Small cascades (12 to 18 inched high) occur approximately
every 40 feet. Riparian vegetation is similar to the previous reach, and extends
approximately 20 feet east of the stream and 100 feet to the west. These stream
conditions prevail southward to the limits of the study area (Photographs 32 through 34).
Stream Description: Tributaries to North Fork Hylebos Creek
Tributary 1 drains the southwest portion of Wetland 32-21-4-119. It is a small stream,
approximately 18-24 inches wide at the OHWM (Photograph 35). Tributary 1 begins at a
dense thicket of salmonberry and hardhack, and flows approximately 50 feet to the south
before crossing under South 359th Street in a culvert. The substrate is predominantly
silts and sands, but the flow of water appears relatively rapid and consistent. No pools
were observed.
Tributary 2 flows west to east along the north side of South 359th Street. It is
approximately 50 feet long, and 18-24 inches wide at the OHWM. Tributary 2 begins
near the emergent portion of Wetland 32-21-4-119 near the intersection of South 359th
Street and Pacific Highway South, and flows eastwards to join Tributary 1 approximately
10 feet north of the culvert under South 359" Street. The substrate of Tributary 2
consists of silts and sands. The water in Tributary 2 is slow moving, and the numerous
pools contain iron rich algae.
Stream Ratings
The North Fork of Hylebos Creek is a fish bearing stream. Fish bearing streams in the
City of Federal Way are classified as major streams, and require a standard setback of
100 feet.
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 3561h Street / SR 99 Intersection Improvement Project Page 7
Tributary 1 and Tributary 2 are tributaries to North Fork Hylebos Creek. All tributaries to
fish bearing streams in Federal Way are classified as major streams, and require a
setback of 100 feet.
Summary
No wetlands were identified on the proposed South 356th Street alignment. A large
wetland (Wetland 32-21-4-119) was identified on to the south of the proposed alignment,
and a second smaller wetland was located to the southeast of the alignment. Wetland
32-21-4-119 is rated Category I by the City of Federal Way, and the required 200 foot
buffer would likely extend into the proposed alignment. A Jurisdictional Determination
should be requested from the US Army Corps of Engineers to confirm the boundary of
Wetland 32-21-4-119 and Wetland 2 in the project vicinity.
North Fork Hylebos Creek flows east and south across the study area. North Fork
Hylebos Creek is classified as a major stream by the City of Federal Way, and requires a
100 foot buffer. This stream buffer extends extend south and west of the stream onto
the proposed alignment. Two smaller tributaries are present along South 359th Street.
Buffers and setbacks for these streams are either within existing wetlands or paved
areas of South 359th Street.
Construction of the proposed improvements for the South 3561h Street/SR 99
Intersection Improvements Project will affect North Fork Hylebos Creek, its buffer, and
the buffer of Wetland 32-21-4-119.
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 35e Street / SR 99 Intersection Improvement Project Page 8
REFERENCES
Cooke, S.S. 1997. A Field Guide to the Common Wetland Plants of Western Washington and
Northwest Oregon. Seattle Audubon Society, Seattle, Washington.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and
deepwater habitats of the United States. Government Printing Office, Washington, D.C.
Ecology (Washington State Department of Ecology). 1997. Washington State wetland
identification and delineation manual, Publication #96-94. Olympia, Washington.
Environmental Laboratory. 1987. Corps of Engineers Wetland Delineation Manual. Technical
Report Y-87-1, Environmental Laboratory, Department of the Army, Waterways
Experiment Station, Vicksburg, Mississippi.
Federal Way, City of. Federal Way Community Code. (Available online at
http://search.mrsc.org/nxtl ateway.dl]/Cdwyinc?f=templates&fn=fdwypage.htm$vid=mun
icodes:FederalWay (City of Federal Way, Wa.
Federal Way, City of. 2002. Pacific Avenue Road Improvements for the New High School in
Federal Way, Sensitive Areas Study. Prepared by Adolfson Associates, Inc. for the City
of Federal Way. Federal Way, Washington.
Friends of the Hylebos Wetlands website(http:l/www.hylebos.org/index.htm7. Accessed
December, 2005.
Greytag Macbeth Corporation. 1994. Munsell soil color charts.
HDR Engineering, Inc. 2005. Wetland Reconnaissance Technical Memorandum. Prepared for
the City of Federal Way, Federal Way, Washington.
Hitchcock, C.L. and A. Cronquist. 1973. Flora of the Pacific Northwest. University of
Washington Press, Seattle, Washington.
King County Wetland Inventory(http:llwww.metrokc.gov/gis/mapportal/iMAP_main.htm
Accessed December, 2005.
NRCS (Natural Resource Conservation Service). 2003. Field Indicators of Hydric Soils in the
United States. U. S. Department of Agriculture in cooperation with the National
Technical Committee for Hydric Soils.
Pojar, J. and A. MacKinnon. 1994. Plants of the Pacific Northwest Coast. Lone Pine Publishing,
Redmond, Washington.
Reed, P.B., Jr. 1997. Revision of the national list of plant species that occur in wetlands. U.S.
Department of Interior, Fish and Wildlife Service. Washington, D.C.
Snyder, D.E., P.S. Gale, and R.F. Russell. 1973. Soil Survey of King County Area, Washington.
USDA Soil Conservation Service, In Cooperation with Washington Agricultural
Experimental Station. United States Government Printing Office, Washington D.C.
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 35e Streetl SR 99 Intersection Improvement Project Page 9
USDA, NRCS (U.S. Department of Agriculture, Natural Resources Conservation Service). 2004.
The PLANTS Database, Version 3.5 (http:llplants.usda.gov). National Plant Data Center,
Baton Rouge, LA 70874-4490 USA.
USFWS (U,S. Fish and Wildlife Service). 2004. National Wetland Inventory, Renton,
Washington Quadrangle. http:I/wetlandsfws.er.usgs.gov/wtlnds/launch.html. U.S.
Department of Fish and Wildlife Service. Portland, Oregon.
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 356`h Street / SR 99 Intersection Improvement Project Page 10
APPENDIX A
WETLAND DELINEATION METHODS
Wetlands were identified and delineated using the three parameter method described in
Washington State Wetland Identification and Delineation Manual (Ecology, 1997). HDR
Engineering, Inc. staff collected data for each of the three parameters (hydrophytic
vegetation, hydric soils, and wetland hydrology) in areas that represent typical site
conditions. Staff collected additional data in associated uplands as needed to confirm
wetland boundaries. These data were recorded on standard wetland delineation data
sheets (attached).
VEGETATION
The dominant plants and their wetland indicator status were evaluated to determine if
the vegetation was hydrophytic. Hydrophytic vegetation is defined as vegetation
adapted to wetland conditions. To meet the hydrophytic vegetation criterion, more than
50 percent of the dominant plants must be Facultative, Facultative Wetland, or Obligate,
based on the wetland indicator category assigned to each plant species by US Fish and
Wildlife Service (USFWS) (Reed, 1997). Table 1 lists the definitions of the indicator
categories.
Table 1. Definitions of Wetland Plant Indicator Categories used to
Determine the Presence of Hydrophytic Vegetation
Wetland Indicator Category
Symbol
Definition
Obligate Wetland Plants
OBL
Plants that almost always (> 99% of the
time) occur in wetlands, but which may
rarely (< 1% of the time) occur in non -
wetlands.
Facultative Wetland Plants
FACW
Plants that often (67 to 99% of the time)
occur in wetlands, but sometimes (1 to
33% of the time) occur in non -wetlands -
Facultative Plants
FAC
Plants with a similar likelihood (34 to 66%
of the time) of occurring in both wetlands
and non -wetlands.
Facultative Upland Plants
FACU
Plants that sometimes (1 to 33% of the
time) occur in wetlands, but occur more
often (67 to 99% of the time) in non -
wetlands.
Upland Plants
UPL
Plants that rarely (< 1 % of the time) occur
in wetlands, and almost always (> 99% of
the time) occur in non -wetlands.
Source: Reed (1997)
HDR biologists used R Field Guide to the Common Wetland Plants of Western
Washington and Northwest Oregon (Cooke, 1997) and Plants of the Pacific Northwest
(Pojar and MacKinnon, 1994) as field references to assist with plant identification.
Scientific and common plant names follow currently accepted nomenclature. Most
names are consistent with Flora of the Pacific Northwest (Hitchcock and Cronquist,
1973) and the PLANTS Database (USDA, 2004).
Draft Welland and Stream Delineation Technical Memo December 2005
City of Federal Way -- S. 356d" Street I SR 99 Intersection Improvement Project Page 11
HYDROLOGY
Project staff examined the area for evidence of hydrology. Wetland hydrology criteria
were considered to be satisfied if it appeared that the soil was seasonally inundated or
saturated to the surface for a consecutive number of days greater than or equal to 12.5
percent of the growing season. The growing season begins when the soil reaches a
temperature of 41 degrees Fahrenheit in the zone of root penetration. The growing
season in low elevations in western Washington is typically considered to be from March
1 to October 31 (244 days) (Washington State Department of Ecology 1997).
Primary indicators of hydrology include surface inundation and saturated soils.
Secondary indicators of hydrology include drainage patterns, watermarks on vegetation,
water -stained leaves, and oxidized root channels.
SOILS
Generally, an area must contain hydric soils to be a wetland. Hydric soil forms when
soils are saturated, flooded, or ponded long enough during the growing season to
develop anaerobic conditions in the upper part (12 inches). Biological activities in
saturated soil result in reduced oxygen concentrations and organisms turn to anaerobic
processes for metabolism. Over time, anaerobic biological processes result in certain
soil color patterns, which are used as indicators of hydric soil. Typically, low-chroma
colors are formed in the soil matrix, and bright -colored redoximorphic features form
within the matrix. Other important hydric soil indicators include organic matter
accumulations in the surface horizon, reduced sulfur odors, and organic matter staining
in the subsurface (NRCS, 2003).
BOUNDARY IDENTIFICATION
The delineated wetland boundaries were flagged with sequentially numbered, bright pink
flagging. Boundaries were numbered in the order in which they were encountered in the
field, and numbering does not necessarily reflect geographic location. Data plot
locations were flagged with blue and white striped flagging and labeled with the wetland
and plot number. Field data sheets for wetlands are provided in Appendix A.
The ordinary high water marks (OHWMs) of streams were flagged with blue flags on the
Parcel 1, and blue and white striped flags on the Federal Way Parcel. Flags were
generally paired (e.g. 1, 1 a) and consecutively numbered. All delineated wetlands and
streams will be instrument -surveyed and maps will be prepared by the surveyors.
Draft Welland and Stream Delineation Technical Memo December 2005
City of Federal Way - S. 35611 Street / SR 99Intersection Improvement Project Page 12
ATTACHMENT A
FIGURES & SITE PHOTOGRAPHS
Draft Welland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 35e Street / SR 99 Intersection Improvement Project Page 13
Z98 Image Map Page
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Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way - S. 356h Street / SR 99 Intersection Improvement Project Page 14
N98 Image Map Page
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Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 3561h Street / SR 99 Intersection Improvement Project Page 15
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 35eh Street / SR 99 Intersection Improvement Project Page 16
ATTACHMENT B
WETLAND DATA FORMS
Draft Wetland and Stream Delineation Technical Memo December 2005
City of Federal Way — S. 356�h Street / SR 99 Intersection Improvement Project Page 17
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4§�
CITY OF
Federal
APPLICATION NO(S)
Way
Parcel Number(s) f 9,f Lo 11004
MASTER LAND USE APPLICATION
DEPARTMEN-r OF COMMUNITY DEVELOPMENT SERVICES
33325 S'" Avenue South
Federal Way, WA 98003-6325
253-835-2607;Fax 253-835-2609
www.Citvoffedcral way.com
Date 04 03 /r
f
Project Description .1A1XrAt4g itak1
Type of Permit Required
Annexation
Binding Site Plan
Boundary Line Adjustment
Comp Plan/Rezone
Land Surface Modification
Lot Line Elimination
Preapplication Conference
Process I (Director's Approval)
Process H (Site Plan Review)
Process III (Project Approval)
Process IV (Hearing Examiner's Decision)
Process V (Quasi-Jddicial Rezone)
Process VI
SEPA w/Project
SEPA Only
Shoreline. Variance/Conditional Use
Short Subdivision
Subdivision
_Variance: Commercial/Residential
-- 0
Required Information
(X, Zoning Designation
0#6V ,:ilk Comprehensive Plan Designation
Value of Existing Improvements
Value of Proposed Improvements
International Building Code (IBC):
Occupancy Type
'J Construction Type
Applicant
Name: /may - pWcclr6
Address: 3337-S 3rNA(cs
City/State: 10044,4447, L- 28003
Zip:
Phone: #9 85T-- :2 10
Fax.
Email: 7aNY:•-P&QTrC& 4 j' WAZV14A W4'K &I"
Signature: A6 75k—
Agent (if different than Applicant)
Name:
Address:
City/State:
Zip:
Phone:
Fax:
Email:
Signature:
Owner
Name:
Address:
City/State:
Zip:
Phone:
Fax:
Email:
Signature:
Bulletin #003 — January 1, 2011 Page 1 of 1 k:\Iandouts\Master Land Use Application