21-100017_Wetlands Report REV1_4-2-2021 _V2
WETLANDS AND DRAINAGE CORRIDORS
EVALUATION & DELINEATION REPORT
&
Conceptual Wetland Mitigation Plan
for
Reasonable Use Exception
P & M Development Parcels
PARCEL # 1421039069, 1421039087, & 1421039043
33305 43rd Avenue Southwest and adjacent east
CITY OF FEDERAL WAY, WASHINGTON
City File folders #20-104505, 21-100016, 21-100-17
Prepared for:
Ms. Michelle Henry, PE
P & M Development LLC
35001 NE 147TH AVE
Yacolt, WA 98675
p.m.development@outlook.com
360-281-8195
Prepared by
Beaver Creek Environmental Services, Inc.
P. O. Box 731695
Puyallup, WA 98373
253 732-6515
MHeckert@Q.Com
REV. 1 April 2, 2021
EXECUTIVE SUMMARY
The P & M Development Project Site is a 73,495 sq. ft., 1.7-acre project area comprised
of three parcels #s 1421039069, 1421039087, & 1421039043, located at 33305 43rd Ave.
SW and adjacent east, City of Federal Way, Washington. An assessment of this project
area following the procedures outlined in the Corps of Engineers (CoE) Wetland
Delineation Manual - 2010 Western Mountains, Valleys, and Coast (WMVC) Regional
Supplement, Revised Washington State Wetland Rating System (WSWRS), and City of
Federal Way Code 19 (Critical Areas) resulted in the identification of one wetland area
(Wetlands A) and two Aquatic Areas.
Onsite assessment included an evaluation of the function and value rating for each
wetland, a classification of each wetland and stream following the U.S. Fish and Wildlife
Service methods, a categorization of each wetland and stream following City of Federal
Way Code 19 - Critical Areas, and an identification of the standard City of Federal Way
buffer width.
WETLAND SIZE
(acre)
CITY OF
FEDERAL WAY
CATEGORY
WA WETLAND
RATING
SCORE
GENERAL
BUFFER WIDTH
Adjustment by
Function And
Land Use
Buffer
Total
A 18+ II 22 150 ft. 0 ft. 150 ft.
* Wetland size onsite – east, west & north boundary not defined, continues off site
The Seattle District U.S. Army Corps of Engineers, the Washington Department of
Ecology, and City of Federal Way (as well as a number of other resource agencies)
regulate activities in and around identified wetland and stream areas. Such regulations
focus on the avoidance of adverse impacts to wetlands and the mitigation of such impacts
that cannot be avoided. In addition, City of Federal Way has established criteria to
categorize wetlands for purposes of regulation and requires a buffer along wetland and
drainage corridor areas.
As presently defined for the site the proposed action is to site single-family house on each
parcel.
These parcels are zoned residential. Regulated wetlands and their buffers encompass
the entire site. To enable development, the wetland and stream buffers must be reduced
substantially. No regulated wetland will be impacted. Due to site conditions, the buffers
must be reduced to accommodate development. Reasonable Use Exception or variance
is required to enable development. Minimized portions of each parcel is dedicated to the
homesite. The remainder of each parcel is to be fenced and remain undeveloped.
TABLE OF CONTENTS
INTRODUCTION............................................................................................................. 1
STUDY PURPOSE ......................................................................................................... 1
SITE DESCRIPTION ..................................................................................................... 1
BACKGROUND INFORMATION ................................................................................. 2
NATIONAL WETLAND INVENTORY ....................................................................... 2
CITY OF FEDERAL WAY WETLAND INVENTORY ................................................ 2
WDFW PRIORITY HABITS AND SPECIES DATA .................................................................................. 2
SOILS MAPPING ........................................................................................................... 2
ONSITE ANALYSIS ........................................................................................................ 2
CRITERIA FOR WETLAND AND STREAM IDENTIFICATION .............................. 2
STUDY METHODS ....................................................................................................... 3
FIELD OBSERVATION ................................................................................................ 3
WETLAND AND STREAM DETERMINATION ........................................................ 4
WETLAND FUNCTION AND VALUE ASSESSMENT .............................................. 5
SITE WETLAND VALUATION ................................................................................... 6
REGULATORY CONSIDERATION ............................................................................. 6
U.S. ARMY CORPS OF ENGINEERS - SECTION 404 ................................................... 7
STATE OF WASHINGTON DEPARTMENT OF ECOLOGY ..................................... 7
CITY OF FEDERAL WAY ............................................................................................ 8
SELECTED DEVELOPMENT ACTION ...................................................................... 9
IMPACT ASSESSMENT ............................................................................................... 10
CONCEPTUAL MITIGATION PLAN ........................................................................ 11
FIGURES ......................................................................................................................... 12
REFERENCE LIST ........................................................................................................ 13
ATTACHMENT 1 - WETLAND DELINEATION MAPS ......................................... 14
ATTACHMENT 2 .......................................................................................................... 15
WESTERN WASHINGTON - REVISED WASHINGTON STATE WETLAND
RATING SYSTEM(WSWRS) FORM .......................................................................... 15
ATTACHMENT 3 – FIELD DATA FORMS .............................................................. 16
HENRY FedWay WetRept & RUE – REV 1
STANDARD OF CARE
Prior to extensive site planning, this document should be reviewed and the wetland
boundaries verified by the appropriate resource and permitting agencies. Wetland
boundaries, wetland classifications, wetland ratings, and proposed buffers should be
reviewed and approved by City of Federal Way Planning and Land Services and
potentially other regulatory agencies. Beaver Creek Environmental Services, Inc. (BCES)
has provided professional services that are in accordance with the degree of care and
skill generally accepted in the nature of the work accomplished. No other warranties are
expressed or implied. BCES is not responsible for design costs incurred before this
document is approved by the appropriate resource and permitting agencies.
Mark Heckert
BCES
INTRODUCTION
This report details the activities and onsite evaluations undertaken to complete a wetland
and drainage corridor evaluation as an element of the planning and site development of
the P & M Development Site. The P & M Development Project Site is an approx. 1.7-
acre project area comprised of Parcels # 142103-9069, 9087, and 9043, located at 33305
43rd Ave. SW and adjacent east, City of Federal Way, Washington.
The evaluation and delineation of onsite and adjacent wetlands and drainage corridors is
a vital element in the planning and selection of a site development action. The goal of
this approach is to assure that planned site development does not result in adverse
environmental impacts to regulated wetlands, streams, and their associated protective
buffer areas.
Wetlands are generally defined as "those areas that are inundated or saturated by surface
water or ground water at a frequency and duration sufficient to support, and that under
normal circumstances do support, a prevalence of vegetation typically adapted for life in
saturated soil conditions."
(City of Federal Way Title 19).
STUDY PURPOSE
The purpose of this document is to present the results of an onsite assessment and
evaluation of wetland areas within the P & M Development Project Site following the
methods and procedures outlined in the Corps of Engineers (CoE) Wetland Delineation
Manual - 2010 Western Mountains, Valleys, and Coast (WMVC) Regional Supplement
and City of Federal Way Code 19 (Environmentally Critical Areas), and categorized using
the Revised Washington State Wetland Rating System (WSWRS). Drainage corridors
were also assessed in accordance with the criteria established by City of Federal Way
and the State of Washington Department of Natural Resources (WDNR) Forest Practice
Rules (WAC 222-16-030). This study was designed to accommodate site planning and
potential regulatory actions and is suitable for submittal to federal, state, and local
authorities for wetland and stream boundary verification and permitting actions.
SITE DESCRIPTION
This project site is irregular, 73,945 sq. ft. [1.7 acre] total (fig. 2). The site is vacant of
development. The site apparently formally contained a mobile home, and contained huge
quantities of trash. The site has apparently been a dump for many years. The current
owners have removed six containers of trash since owning the site, and the removal is
completed.
HENRY FedWay WetRept & RUE- REV 1
1
2
BACKGROUND INFORMATION
NATIONAL WETLAND INVENTORY
The National Wetland Inventory (NWI) mapping completed by the U.S. Fish and Wildlife
Service was reviewed as a part of this assessment (fig. 3). This mapping resource
identifies no wetlands on the project site. A linear R4SBC (Riverine Intermittent
Streambed Seasonally Flooded) is described flowing generally within the project site.
CITY OF FEDERAL WAY WETLAND INVENTORY
The City of Federal Way Wetland Inventory Mapping was reviewed as a part of this
assessment (fig. 4). This mapping resource identifies a large wetland complex through
the west and north of the project site, designated 14-21-3-4. This wetland has been
characterized by the City as a Category II(2) Wetland. Wetland continues significantly
offsite to the north.
WDFW Priority Habits and species data
WDFW Priority Habitats and Species (PHS) data was reviewed as a part of this
assessment (attached). This mapping resource identified no priority habitats or species
in the project site.
SOILS MAPPING
Soil Resource Report by NRCS was reviewed as a part of this assessment (fig. 5). This
mapping identified the following soils throughout the project site: AgC - Alderwood
gravelly sandy loam, 8 to 15 percent slopes These soils are listed as “hydric”.
ONSITE ANALYSIS
CRITERIA FOR WETLAND AND STREAM IDENTIFICATION
Wetlands are transitional areas between aquatic and upland habitats. In general terms,
wetlands are lands where the extent and duration of saturation with water is the primary
factor determining the nature of soil development and the types of plant and animal
communities living in the soil and on its surface (FGDC, 2013). Wetlands are generally
defined within land use regulations as "areas that are inundated or saturated by surface or
groundwater at a frequency and duration sufficient to support, and that under normal
circumstances do support, a prevalence of vegetation typically adapted for life in saturated
soil conditions" (CoE Manual).
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Wetlands exhibit three (3) essential characteristics, all of which must be present for an area
to meet the established criteria within the Wash. Manual and the CoE Manual. These
essential characteristics are:
1. Hydrophytic Vegetation: A predominance of plants that are typically adapted
for life in saturated soils.
2. Hydric Soil: A soil that is saturated, flooded, or ponded long enough during the
growing season to develop anaerobic conditions in the upper horizons.
3. Wetland Hydrology: Permanent or periodic inundation, or soil saturation to the
surface, at least seasonally.
STUDY METHODS
BCES Consulting completed a specific onsite evaluation of the project area on May 15,
2020. The objective of this evaluation was to define and delineate potential wetland and
drainage corridor areas which may be present within and adjacent to the project area as
defined by the three-parameter criteria test noted within the Wash. Manual and CoE
Manual, and the water-typing criteria noted within the WDNR Forest Practice Rules (WAC
222-16-031).
Boundaries between wetland and non-wetland areas were established by examining the
transitional gradient between wetland and non-wetland characteristics criteria throughout
the site. Delineation was performed using the routine methodology for areas less than
five acres as detailed in the CoE Manual.
FIELD OBSERVATION
As defined by existing site conditions and aerial photos, the project site has experienced
extensive use and development. The site is three residential parcels, which are vacant
now. Prior to cleanup, the site was a dumping ground in addition to the housing debris on
the site. A stream transects the site through the western parcel flowing north. The parcels
appear to have been filled in the area around the entrance road in original development
of the parcel, along the periphery of the wetland. It appears the stream was rerouted to
the west to accommodate the original house placement.
Soils
The majority of the project site was comprised of Alderwood gravelly sandy loam, a non-
wetland soil.
The soils proximal to the access road and continuing north approximately 100 ft. appear
to be installed fill. North of that area of the site soils are dark gray to black silt loam and
peat, with concretions and organic streaking. This area appears to remain saturated to
the surface well into the growing season. The surface soil layer within the Wetlands A
depression was generally silt loam. Soils in Wetland A meet the hydric soil criteria.
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Hydrology
Hydrology within the project area appeared to be the result of hydro support by the
stream, and seasonal storm water runoff from onsite and adjacent properties; long and
short-term seasonal ponding and soil characteristics. The drainages coalesce in the
southwest corner and continues north to a large wetland complex. Stormwater surface
runoff through the overall project area was directed by topography to the north into the
wetland area.
Vegetation
The primary plant community in the mixed forested portion of the property along the north
boundary of the house sites is dominated by trees: Fraxinus latifolia (Oregon ash), Alnus
rubra (Red alder), and a few Salix lasiandra (Pacific willow). This plant community was
identified as hydrophytic in character (i.e. typical of wetlands) in the areas identified as
wetlands in the west portion of the site.
The plant community outside the wetland area was identified as non-hydrophytic in
character (i.e. not typical of wetlands).
WETLAND AND STREAM DETERMINATION
Wetland determination was based on sample plots which contained hydrophytic
vegetation, hydric soils, and wetland hydrology in accordance with the CoE Manual and
the Wash. Manual. Based on these methods one wetland was identified within the project
area. Two areas were identified onsite to exhibit characteristics typical of a stream. One
area was identified onsite to exhibit characteristics typical of a pond.
WETLAND SIZE
(acre)
CITY OF
FEDERAL WAY
CATEGORY
WA WETLAND
RATING
SCORE
GENERAL
BUFFER WIDTH
Adjustment by
Function and
Land Use
Buffer
Total
A 18+ II 22 150 ft. 0 ft. 150 ft.
* Wetland size onsite – east, west & north boundary not defined, continues off site
Wetland A: This wetland is located throughout the site, with the south boundary cutting
across the site east to west and continues substantially offsite to the north, east, and west.
This wetland encompasses the northern portions of each parcel. Hydrology for this
wetland was provided by primarily by overbank flooding from the stream and seasonal
precipitation.
5
The buffer for Wetland A has been cleared and landscaped to the wetland edge as part
of previous development.
Since this wetland scored 22 Points by WSWRS, this wetland appeared to meet the
criteria for designation as a City of Federal Way Category II (2) Wetland. General buffer
for a City of Federal Way Category II Wetland is 165 ft. The Wetland Buffer of this wetland
encompasses the entire site.
Stream A: Stream A is identified as a stream which originates south of the project site
and flows onsite from the south. This stream provides habitat for both anadromous and
resident fish species downstream of the site. No evidence of potential for fish habitat was
found for the portion of the stream on or near the site. This stream is designated as a
Type F water. Type F streams require a 100 ft. buffer from the stream edge [Ordinary
High-Water Mark]. Within the project site, the stream buffer is subsumed by the wetland
buffer. This feature is identified as Joes Creek with the City Permanent Identifier
#155182521
Stream B: Stream B is a stream which originates a short distance southwest of the
project site. This stream meets the criteria for designation as a Type N water. Type N
streams require a 65 ft. buffer from the stream edge [Ordinary High-Water Mark]. Within
the project site, the stream buffer is subsumed by the wetland buffer. This feature is
identified as Joes Creek with the City Permanent Identifier #155182521
Offsite Wetlands: Wetland A continues substantially offsite to the east, north, and west.
WETLAND FUNCTION AND VALUE ASSESSMENT
Wetlands are known to perform significant roles in the ecosystem, some of which are of
immediate value to society. These roles vary greatly with the size, type, hydrology,
vegetation, and location of wetland areas. Although the ecological functions performed
by these wetlands are complex, interrelated, and difficult to assess and quantify, methods
have been developed for the U.S. Army Corps of Engineers (FGDC, 2013). The functions
provided by wetlands include hydrologic support, shoreline protection, stormwater and
floodwater storage, water quality, groundwater recharge, and provision of wildlife habitat.
CATEGORIZATION BASED ON FUNCTIONS
The functions that a wetland performs are characterized by answering a series of
questions that note the presence, or absence, of certain indicators. Indicators are easily
observed characteristics that are correlated with quantitative or qualitative observations
of a function (Hruby et al. 2000).
Depressional or Flats Wetlands
Potential to Improve Water Quality
Potential to Reduce Flooding and Stream Erosion
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Riverine and Freshwater, Tidal Fringe Wetlands
Potential to Improve Water Quality
Potential to Reduce Flooding and Stream Erosion
Opportunity to Reduce Flooding and Stream Erosion
Lake-fringe Wetlands
Potential to Improve Water Quality
Opportunity to Improve Water Quality
Potential to Reduce Shoreline Erosion
Opportunity to Protect Resources from Shoreline Erosion
Slope Wetlands
Potential to Improve Water Quality
Opportunity to Improve Water Quality
Potential to Reduce Flooding and Stream Erosion
Opportunity to Reduce Flooding and Erosion
Functions Related to Habitat for All Classes of Wetlands
Potential to Provide Habitat
Opportunity to Provide Habitat
Score and Category Based on Functions
Wetlands that are Category I based on functions need to score 23 points or more. Total
scores between 20-22 are Category II; 16-19 are Category III, and less than 19 are
Category IV.
SITE WETLAND VALUATION
The wetland areas identified within the overall project area were evaluated following the
functional value assessment process noted above.
As identified in this assessment Wetland A would be considered to have the overall
functional rating of Category 2.
Water Quality Functions – 8 points
Hydrologic Functions – 8 points
Habitat Functions – 6 points
TOTAL score for functions – 22 points
REGULATORY CONSIDERATION
The proposed alteration of lands defined by various federal, state, and local authority
rules and regulations as "wetlands" raises environmental concerns that are generally
addressed in the development review process. These concerns center on the
development's potential adverse impacts to the structure, function, value, and size of
7
these "wetland" areas. Such adverse impacts may include a reduction in wildlife habitats,
reduced surface water quality, reduced water retention, a reduced ground water recharge
rate, reduced plant species diversity, and the reduction in the function and value of other
associated wetland and non-wetland characteristics.
U.S. ARMY CORPS OF ENGINEERS - Section 404
Section 404 of the Clean Water Act (33 U.S.C. 1344) prohibits the discharge of dredged
or fill material into "Waters of the United States" without a permit from the Corps of
Engineers (Corps). The Corps has jurisdiction over freshwater systems waterward from
the ordinary high water line of a water body or waterward from the upland boundary of
the adjacent wetland. The definition of fill materials includes the replacement of aquatic
areas with dry land, grading which changes the surface contour of a wetland, and
mechanized land clearing in wetlands. For the purposes of Section 404 permitting the
Corps makes the final determination as to whether an area meets the wetland definition
and would be subject to regulation under the Corps program.
Currently the Corps has two specific types of permits which apply to wetland fill proposals.
These two types are a series of specific Nationwide Permits and the Individual Permit.
The Nationwide Permit process identifies specific categories of work that can be
undertaken following a set of specific conditions applicable to each Nationwide Permit
number.
The Corps requires an Individual Permit where a proposed activity within an identified
jurisdictional wetland area can not be authorized under one of the Nationwide Permits.
Within the Individual Permit process the Corps undertakes a much more in-depth review
of the proposed project and the proposed impacts. The Corps must evaluate whether the
benefits derived from the project outweigh the foreseeable environmental impacts of the
project's completion.
All projects that proceed forward using either one of the Nationwide Permits or the
Individual Permit process must also comply with the provisions of the Endangered
Species Act.
As defined by a recent U.S. Supreme Court decisions the Corps of Engineers does not
typically regulated “isolated” wetlands pursuant to Section 404 of the Clean Water Act.
Under this decision “isolated” wetlands do not exhibit a continuous surface water
connection to other, downstream aquatic system.
STATE OF WASHINGTON DEPARTMENT OF ECOLOGY
Proposed action undertaken through either of the Corps of Engineers processes
(Nationwide or Individual) are also subject to the provisions of the Washington State
Department of Ecology Section 401 Water Quality Certification Process. Projects that
may be exempt from Corps of Engineers Section 404 jurisdiction may still require review
8
by the Washington State Department of Ecology to ensure consistency with State water
quality protection provisions.
CITY OF FEDERAL WAY
19.145.420 Wetland rating and buffers.
(1) Rating. Wetlands shall be rated according to the Washington Department of Ecology wetland
rating system, as set forth in the Washington State Wetland Rating System for Western
Washington – 2014 Update (Ecology Publication No. 14-06-029, or as revised and approved by
Ecology), which contains the definitions and methods for determining whether the criteria below
are met:
(a) Category I wetlands represent a unique or rare wetland type; are more sensitive to disturbance
than most wetlands; are relatively undisturbed and contain ecological attributes that are
impossible to replace within a human lifetime; or provide a high level of function. The following
types of wetlands are Category I:
(i) Wetlands of high conservation value that are identified by scientists of the Washington
Natural Heritage Program/Department of Natural Resources;
(ii) Bogs;
(iii) Wetlands with mature and old growth forests larger than one acre; and
(iv) Wetlands that perform functions at high levels (wetlands that score 23 points or more based
on functions).
(b) Category II wetlands are difficult, though not impossible, to replace, and provide high levels
of some functions. Category II wetlands are those wetlands that score between 20 and 22 points
based on functions.
(c) Category III wetlands are wetlands with a moderate level of functions that score between 16
and 19 points based on functions.
(d) Category IV wetlands are wetlands with the lowest level of functions (scoring less than 16
points based on functions) and are often heavily disturbed.
(2) Wetland buffers shall be measured perpendicular from the wetland boundary as delineated
and marked in the field. Buffer widths are established as follows in Table 1:
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Table 1
Wetland Category Buffer Width
(wetland scores 3-
5 habitat points)
Buffer Width
(wetland scores
6-7 habitat
points)
Buffer Width
(wetland scores
8-9 habitat
points)
Category I: Bogs and wetlands of high
conservation value
250 feet 250 feet 300 feet
Category I: Forested and based on
function score
100 feet 150 feet 300 feet
Category II 100 feet 150 feet 300 feet
Category III 80 feet 150 feet 300 feet
Category IV 50 feet 50 feet 50 feet
(3) No wetland buffer is required for those isolated wetlands 1,000 square feet or less in total
area.
(4) All compensatory mitigation sites shall have buffers consistent with the buffer requirements
of this section. Buffers shall be based on the expected or target category of the proposed wetland
mitigation site.
(5) Lighting shall be directed away from wetland buffers unless otherwise determined by the
director.
(6) All lots approved in a recorded subdivision or binding site plan that contain wetlands and
their associated buffer in a native growth protection easement or tract may be improved pursuant
to easement or tract boundaries established in the plat regardless of subsequent regulatory buffer
increases or natural migration.
(7) All wetland and wetland buffer boundaries shown on an approved use process decision
and/or building permit shall be honored regardless of subsequent regulatory buffer increases or
natural migration.
SELECTED DEVELOPMENT ACTION
As presently defined for the site the proposed action is to develop each of the three
parcels to single-family homesites in concurrence with City of Federal Way regulations.
The area is zoned residential. Each of the three parcels is totally encompassed by
wetlands, streams, and their buffers. To develop these sites impacts to the wetland and
stream buffers is required. A required sewer connection will pass through the wetland
and will be mitigated.
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Impact Assessment
The proposed onsite action selected focuses on the impact of site development activities
on the Critical Areas (wetland and buffer) on the site (See attachment 2).
Stream Crossing
The project requires a sanitary sewer extension across the creek to connect to the existing
public sewer adjacent to lot -9043 (west) as shown on the engineering plans. The project
proposes installing an 1-1/4” low pressure sewer pipeline under the creek and up the hill
to the existing sewer manhole. There will be no in water work. The pipeline will be
directionally bored to minimize impacts to the creek and surrounding vegetation. The bore
pit will be located approximately 250 feet away from the location of the creek crossing.
The new pipeline will cross the creek at a minimum depth of 4-ft below the bottom scour
of the creek bed. The entire extension of new sewer is approximately 450 feet long and
will be continuously bored. Boring is a non-evasive trenchless construction method that
will not adversely impact the creek or existing habitat.
The proposed stream crossing for utility connection meets all applicable criteria per
FWRC 19.145.320 and in particular 2 (g) for utility crossings and 2 (h) for a single crossing
to serve multiple lots.
Stormwater Runoff
Full dispersion methods will be used in treating and controlling stormwater runoff from the
site development as shown on the engineering plans. The project design funnels runoff
to dispersion trenches with natural vegetated flow paths to fully disperse impervious
surfaces in meeting the requirements of the King County Surface Water Design Manual
for both flow control and water quality within the buffer of critical areas. Meeting the
prescriptive design requirements set forth by King County provides for the buffer to
function at an equivalent level to the standard buffer. The Stormwater Report submitted
with the proposed project provides a detailed site analysis including a level 1 offsite
analysis.
In addition to this, an enhanced buffer area is proposed with the following mitigation plan.
Impact Area Analysis –
Area BUFFER Area Impacted
(square feet)
Mitigation
East Parcel 3,150 4,548
Central Parcel 2,800 3,211
West Parcel 3,250 2,025
TOTAL 9,200 9,784
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Conceptual Mitigation Plan
The development scheme for these parcels relies on the mitigation sequence of
Avoidance, Minimization, Mitigation.
Single-family houses are the zoning for the site and are the least-impactful development
of the site which the zoning allows. The house sites are situated as close to the internal
access road, and each other as allowed by code. The clearing sizes are the minimum
possible for the development of the parcels. The houses are as far away from the wetland
and stream as the parcels allow. The houses sizes are in accord with those in the
neighborhood.
The wetland is heavily vegetated throughout, with the exception of the south end where
it abuts the proposed development area. This area, of 9,784 Sq. Ft. is proposed for a
mitigation planting. It appears to be the edge of the long-ago placed fill, and is dominated
by Reed canarygrass.
Vegetating this area will provide an inhibition of surface erosion into the wetland and
stream, and will provide an auditory and visual barrier between the development and the
wetland. This will protect the functions and values
Planting proposed:
9,784 sq. ft. x 0.012 = 118 trees, ½ to be conifers
9,784 sq. ft. x 0.028 = 275 shrubs
All disturbed areas reseeded with buffer emergent mix.
The mitigation area, and the wetland, will be fenced to inhibit access and no other action
planned for the area north of the silt & permanent fence.
A detailed mitigation Plan will follow City concurrence with the concept mitigation plan
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FIGURES
13
REFERENCE LIST
Adamus, P.R., E.J. Clairain Jr., R.D. Smith, and R.E. Young. CoE. Wetland Evaluation
Technique (WET); Volume II: Methodology, Operational Draft Technical Report Y-87,
U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands
and Deepwater Habitats of the United States. Office of Biological Services, U.S. Fish
and Wildlife Service, U.S. Department of the Interior, FWS/OBS-79/31.
Environmental Laboratory. CoE. "Corps of Engineers Wetlands Delineation Manual,"
Technical Report Y-87-1, US Army Engineer Waterways Experiment Station, Vicksburg,
Miss.
Federal Geographic Data Committee. 2013. Classification of wetlands and deepwater
habitats of the United States. FGDC-STD-004-2013. Second Edition. Wetlands
Subcommittee, Federal Geographic Data Committee and U.S. Fish and Wildlife Service,
Washington, DC.
Hitchcock, C.L., A. Cronquist. 1977. Flora of the Pacific Northwest. University of
Washington Press. Seattle, Washington.
Reppert, R.T., W. Sigleo, E. Stakhiv, L. Messman, and C. Meyers. 1979. Wetland
Values - Concepts and Methods for Wetland Evaluation. Research Report 79-R1, U.S.
Army Corps of Engineers, Institute for Water Resources, Fort Belvoir, Virginia.
U.S. Department of Agriculture, Soils Conservation Service. Soils Survey of King
County Area Washington, February 1979.
U.S. Army Corps of Engineers. 2010. Regional Supplement to the Corps of Engineers Wetland
Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0), ed. J. S.
Wakeley, R. W. Lichvar, and C. V. Noble. ERDC/EL TR-10-3. Vicksburg, MS: U.S. Army
Engineer Research and Development Center
Washington State Department of Ecology. 1997. Washington State Wetlands
Identification and Delineation Manual. Publication Number 96-94.
Washington State Department of Fisheries, Catalog of Washington Streams and
Salmon Utilization, Volume 1., 1975
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ATTACHMENT 1 - WETLAND DELINEATION MAPS
HENRY FED WAY Parcel #1421039069, 1421039087, & 1421039043 - RATING FIGURES
Figure 1. Cowardin Plant Class
Figure 2. Hydroperiod
PFO
PEM
SATURATED ONLY
SEASONALLY FLOODED OR INNUNDATED
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ATTACHMENT 2
Western Washington - Revised Washington State Wetland Rating System(WSWRS)
form
Figure 3. 150-Ft. Buffer & Outlet
Figure 4. Watershed
OUTLET
Source: Esri, Maxar,
GeoEye, Earthstar
DUMAS BAY WATERSHED
Hylebos Creek
Dumas Bay
Lower Puget Sound - DM/Fed Way
Lower Green River - West
Mill Creek
Browns Dash Point
Browns Dash Point
Browns Dash Point
Lower White River
Source: Esri, Maxar,
GeoEye, Earthstar
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ATTACHMENT 3 – Field Data Forms
Figure 5. 1 Km Poly with Accessible & Undisturbed
Figure 6. TMDLs for watershed
DUMAS BAY WATERSHED
UNDISTURBED
UNDISTURBED
UNDISTURBED
UNDISTURBED
ACCESSABLE
Source: Esri, Maxar,
GeoEye, Earthstar