HomeMy WebLinkAboutRS_Critical_Areas_Report_190419_v1.pdf
314 WEST 15TH STREET
VANCOUVER, WA 98660
360.695.3488 MAIN
866.727.0140 FAX
PBSUSA.COM
Critical Areas Report for the Dale Walker Property
3400 East Valley Road
Renton, WA 98057
April 2018
PBS Project No. 41482.000
RECEIVED
04/23/2019
amorganroth
PLANNING DIVISION
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
I
April 2108
PBS Project No. 41482.000
TABLE OF CONTENTS
1 INTRODUCTION ........................................................................................................................................... 1
2 SITE DESCRIPTION ....................................................................................................................................... 1
2.1 Location and Setting ................................................................................................................................................................ 1
2.2 Site History ................................................................................................................................................................................... 1
2.3 Hydrology ..................................................................................................................................................................................... 2
2.4 Soils ................................................................................................................................................................................................. 2
2.5 Vegetation Communities ........................................................................................................................................................ 2
2.5.1 Historic Vegetation Communities .......................................................................................................................... 2
2.5.2 Existing Vegetation ....................................................................................................................................................... 3
3 CRITICAL AREAS ........................................................................................................................................... 3
3.1 National and Local Wetland Inventories .......................................................................................................................... 3
3.2 Wetland Delineation Methods ............................................................................................................................................. 3
3.2.1 Rationale for Delineation Methods ........................................................................................................................ 3
3.2.2 Office Methods .............................................................................................................................................................. 3
3.2.3 Field Methods ................................................................................................................................................................. 3
3.2.4 Growing Season ............................................................................................................................................................. 4
3.2.5 Climate .............................................................................................................................................................................. 4
3.3 Delineation Results ................................................................................................................................................................... 5
3.3.1 Soils..................................................................................................................................................................................... 5
3.3.2 Hydrology......................................................................................................................................................................... 6
3.3.3 Vegetation........................................................................................................................................................................ 6
3.4 Wetland Rating and Buffers .................................................................................................................................................. 6
3.5 Regulatory Framework ............................................................................................................................................................ 7
4 IMPACT ASSESSMENT ................................................................................................................................. 7
5 RESTORATION PLAN ................................................................................................................................... 8
5.1 Goals and Objectives ................................................................................................................................................................ 8
5.2 Performance Standards ........................................................................................................................................................... 8
5.3 Restoration Activities ............................................................................................................................................................... 8
5.3.1 Fill Removal/ Grading/ Site Preparation .............................................................................................................. 8
5.3.2 Native Plantings ............................................................................................................................................................. 8
5.3.3 Follow-up Weed Control ............................................................................................................................................ 9
5.4 Maintenance and Monitoring of Restoration ............................................................................................................... 10
5.5 Contingency Measures .......................................................................................................................................................... 11
6 REFERENCES ...............................................................................................................................................12
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
II
April 2018
PBS Project No. 41454.000
SUPPORTING DATA
TABLES
Table 1. Precipitation Data
Table 2. Wetland Characteristics, Rating and Buffers
Table 3. Performance Standards
Table 4. Planting Plan
PHOTOGRAPHS
FIGURES
Figure 1. Site Vicinity
Figure 2. City of Renton Mapped Wetlands and Streams
Figure 3. National Wetland Inventory
Figure 4. Wetland Delineation Map
Figure 5. Restoration Planting Plan
Figure 6. Mitigation Monitoring Plan
APPENDICES
APPENDIX A: Wetland Delineation Datasheets
APPENDIX B: Wetland Rating Forms
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
1
April 2018
PBS Project No. 41482.000
1 INTRODUCTION
PBS Engineering and Environmental, Inc. (PBS) has prepared the following Critical Area Report for a property
recently purchased by Mr. Dale Walker and being proposed for development as a new car dealership. The site
was operated as an auto junk yard and auto repair shop for at least 50 years prior to being purchased by Mr.
Walker. Most recently the property was doing business as South End Auto Wrecking, Inc. Various forms of
contamination have been identified at the site and cleanup efforts will likely include removal of some of the
contaminated soils. Stemen Environmental is coordinating a cleanup of the site under Ecology’s voluntary
cleanup program. Mr. Walker has cleared the vehicles and trash off the site in preparation for development of
the lot. The City of Renton requested a wetland delineation prior to any excavation or grading of the site.
Before PBS could conduct the delineation, Mr. Walker had someone clear the vegetation at the east edge of
the property. The clearing extended across a City identified wetland at the east edge of the site onto the
Washington State Department of Transportation (WSDOT) right-of-way for State Route 167. This report
identifies the wetland boundary, assesses the impacts to the wetland from the clearing activity, and includes a
restoration plan for restoring wetland vegetation.
2 SITE DESCRIPTION
2.1 Location and Setting
The property is located at 3400 East Valley Road, inside the City limits of Renton, WA. It is in the NE quarter of
Section 30, Township 23 North, Range 05 East. The property consists of a single tax lot (King County tax parcel
3023059067) totaling approximately 5.65 acres (Figure 1). The approximate center of the site is at latitude
47.449707, longitude -122.216895. The property is in the Lower Green – Duwamish watershed in the
Duwamish-Green River Water Resource Inventory Area (WRIA 9).
The Walker property borders East Valley Road on the west side, State Route 167 to the east, and commercial
properties to the south and north. The property sits in a regional low-lying area that was once part of a large
wetland complex at the junction of the Cedar, Black, and Green Rivers. An historic map shows a small stream
running through the middle of the property from the southeast corner to the west side. The project site is
relatively flat with elevations ranging from 16 feet above sea level near the northeast corner and the
southwest corner to 24 feet near the middle of the site. Most of the surface drainage is towards the southwest
corner, with some drainage flowing to the east.
2.2 Site History
The property was used for agricultural land until the 1950’s or 1960’s Since then it has been used as an auto
junkyard and auto repair facility. Historic aerials from 1936 and 1940 show agricultural fields across the entire
area. No obvious wetlands are visible on these photos and any stream that may have been present has likely
been ditched. Highway 167 was built in the 1960’s and a 1964 aerial shows the south half and the west third
of the north half of the property cleared with fill placement likely. By 1968 the entire property is being used as
an auto junkyard except for a strip of vegetation along the east edge.
In 2008, WSDOT widened SR 167 extending the roadway approximately 30 feet to the west and constructing a
rock gabion retaining wall just east of the subject property. The retaining wall was designed to limit impacts to
a wetland that extended nearly a mile along the west edge of the roadway.
In October of 2017, the eastern portion of the property and the adjacent WSDOT right-of-way was cleared of
trees and shrubs. Some of the logs and brush were left in the wetland, some appear to have been collected in
slash piles outside the wetland, and some appear to have been chipped in place.
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
2
April 2018
PBS Project No. 41482.000
WSDOT sent notification of the incident to Washington Department of Ecology, the City of Renton, the US
Army Corps of Engineers, the Washington Department of Fish & Wildlife, and the Muckleshoot tribe. Mr.
Walker is currently working with WSDOT on resolution of the unauthorized clearing and restoration of the
wetland vegetation.
2.3 Hydrology
The property is in the Panther Creek watershed. Panther Creek flows into Springbrook Creek, which in turn
flows into the Black River and then the Green/Duwamish River. The site is part of the Duwamish – Green Water
Resource Inventory Area (WRIA 9). The hydrology of this area has been dramatically changed over the last
century with the lowering of Lake Washington which dried up much of the Black River, redirection of the
Cedar River flows from the Black and Green Rivers into Lake Washington, and filling of vast areas of wetland
and conversion of the floodplain and wetlands to commercial and industrial uses. Hydrology at the site
currently comes primarily from direct precipitation, high groundwater, and stormwater runoff. There is a
culvert connection under SR 167 near the south end of the property that allows water to pass through
between the Panther Creek wetlands to the east of the Highway and the wetland between the west side of the
highway and the subject property. Water level readings in wells installed by Stemen Environmental show
water levels 7 to 10 feet below the ground surface across much of the site during the dry season and near the
surface during the wet season, particularly in the southwest corner. Based on data from the wells,
groundwater flow appears to be towards the west and the Green River. Surface flows on the site are towards
the southwest corner and the east side of the property.
Historic aerials show a stormwater pond constructed in 2011 in the southwest corner of the subject property.
According to Mr. Stemen, water was pumped out of the pond east towards the southeast corner, where it was
filtered in an oyster shell pit before entering the wetland. This stormwater treatment facility is visible on
photos starting in 2012 and was approved by Ecology. The pumps have since been removed and water now
overflows the stormwater pond across much of the southwest corner of the site. The remains of the
stormwater pond and the oyster shell pit were found during the site visit. An east/west ditch across the
property is visible on aerials in the southern half of the property. Portions of this ditch were still present
during the site visit, though no direct connection to the wetland was observed. At the time of the site visit,
there was shallow ponded water in much of the southwest corner and water up to 2 feet deep in the wetland
on the WSDOT right-of-way.
2.4 Soils
Soils are mapped as urban land across the subject property due to high levels of disturbance (NRCS 2017). To
the west, across East Valley Road, soils are mapped as Tukwila Muck. To the east on the other side of SR 167,
soils are mapped as Seattle Muck. Both soils are deep, poorly drained organic soils that formed in herbaceous
and woody deposits in depressions and river valleys. Surface soil on the property is nearly all fill material.
Some remnants of the original muck soils are found in the wetland in the WSDOT right-of-way.
2.5 Vegetation Communities
2.5.1 Historic Vegetation Communities
The property would have probably originally supported a mix of upland forested and forested, scrub-shrub
and emergent wetland communities. Black cottonwood (Populus balsamifera), western red-cedar (Thuja
plicata), red alder (Alnus rubra). Pacific willow (Salix lucida ssp lasiandra) and Sitka spruce (Picea sitchensis)
would have been present in the forested wetland areas. Shrubs likely included willows (Salix sp), red-osier
dogwood (Cornus sericea), black twinberry (Lonicera involucrata), Douglas spirea (Spirea douglasii) and others.
Sedges (Carex sp), rushes (Juncus sp, Scirpus sp) and a variety of other herbaceous plants would have also
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
3
April 2018
PBS Project No. 41482.000
been present. The original forest and wetlands were likely logged, cleared and drained over a century ago to
make way for agricultural fields and then commercial and industrial development.
2.5.2 Existing Vegetation
For the last 50 years or more, there has been very little vegetation on the site except for some narrow fringes
of mostly weedy species along the edges. There was a forested wetland on the WSDOT right-of-way just east
of the property. Based on vegetation on the properties to the north and south and remaining vegetation in th,
this area, the vegetation in the right-of-way consisted of an overstory of black cottonwood and Pacific willow,
with red-osier dogwood, Douglas spirea and Himalayan blackberry in the shrub layer and reed canary grass
(Phalaris arundinacea), slough sedge (Carex obnupta), and horsetails (Equisetum sp) in the understory. Other
species may also be present, but were not identifiable at the time of the site visit in December.
3 CRITICAL AREAS
3.1 National and Local Wetland Inventories
The National Wetland Inventory (NWI) maps a 1.6 acre palustrine, forested, seasonally flooded wetland just
east of the property along the west side of SR 167 extending north from the subject property. A 25-acre
palustrine, emergent and scrub-shrub, semi-permanently flooded wetland is mapped on the east side of SR
167 that extends north to SR 405. Several other emergent and scrub-shrub wetlands are shown south of this
larger wetland. A palustrine forested wetland associated with Panther Creek is also mapped along the east
side of SR 167. All of these wetlands are part of a wetland complex associated with Panther Creek and Rolling
Hills Creek that has been fragmented by SR 167 and other development. The City of Renton wetland maps
show a 52-acre wetland on the east side of SR 167 and a 3-acre wetland on the west side of SR 167. While the
NWI map shows wetland extending only halfway along the east side of the property, the City of Renton
wetland maps show the wetland extending along the entire east edge of the property and continuing over
600 feet south of the property boundary. Figure 2 shows the City mapped wetlands and Figure 3 shows the
NWI mapped wetlands.
3.2 Wetland Delineation Methods
3.2.1 Rationale for Delineation Methods
Based upon guidance provided in the Corps of Engineers 1987 Wetland Delineation Manual (1987 Manual) and
the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys
and Coast Supplement (Version 2.0) (WMVC Regional Supplement), it is the best professional judgment of the
PBS delineation team that the current wetlands in the study area still exist under reasonably “normal
circumstances” as defined in the 1987 Manual and supplement despite the recent clearing. Wetland soils and
hydrology are still present. Remnants of the cleared vegetation along with reference vegetation to the north
and south allowed for inference of wetland vegetation at the site pre-clearing. Therefore, we delineated
waters and wetlands on the project using methods recommended in the manual for normal circumstances.
3.2.2 Office Methods
Office preparation for the delineation consisted of reviewing a variety of online sources including aerial
photographs, City of Renton GIS layers, King County iMAP, soils maps and descriptions, weather history, site
history, etc.
3.2.3 Field Methods
Katharine Lee, a Professional Wetland Scientist, and Kevin Hood conducted a field visit on December 13, 2017.
The wetland was delineated using the three-parameter approach as required in the WMVC Regional
Supplement, with extrapolation of vegetation based on remaining vegetation, stumps and intact vegetation to
the north and south. A Magellan handheld GPS unit with post-processing and sub-meter accuracy was used
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
4
April 2018
PBS Project No. 41482.000
to map the location of wetland flags and data plots. The wetland sits in a defined depression with a retaining
wall on the east side along SR 167 and a fill prism on the west side.
3.2.3.1 Hydrology
The presence of wetland hydrology was determined by evaluating a variety of direct and indirect
indicators. In addition to direct hydrologic measurements, hydrologic indicators can be used to infer
satisfaction of the wetland hydrology criterion. Field indicators of wetland hydrology listed in the Regional
Supplement include, but are not limited to, visual observation of inundation or saturation, sediment
deposition, hydric soil characteristics, watermarks, drift lines, oxidation around living roots and rhizomes,
and water-stained leaves. To satisfy the hydrology criterion for wetlands, soils need to be inundated or
saturated to the surface for at least 14 consecutive days during the growing season. The site visits occurred
at the end of, or just outside the growing season for this area. Primary hydrologic indicators in the form of
saturated soils, high groundwater and inundation were present at the time of the site visit.
3.2.3.2 Soils
The presence of hydric soils was determined consistent with the WMVC Regional Supplement and current
regulatory guidance. The supplement includes hydric soil indicators specific to this region. Soils were
evaluated based on these indicators. The extent and depth of historic fill generally defines the current
wetland boundary with the wetland extending into the edge of the fill. Fill material was a mix of silty, sandy,
gravelly material with varying types of debris.
3.2.3.3 Vegetation
No vegetation was present on the upland areas at the time of the site visit and while upland areas
appeared to have recently been graded during the removal of vehicles, it does not appear any vegetation
had been previously present based on historic aerials. The vegetation in the wetland had recently been
cleared, removing all the trees and most of the shrubs. Stumps were still present along with a few shrubs
and some herbaceous vegetation. Because of this, vegetation was not a reliable indicator of the
wetland/upland boundary except offsite at the north and south edges.
Species identifications and taxonomic nomenclature followed the USDA Plants Database. Each species'
indicator status was assigned using the Western Mountains, Valleys, and Coast 2016 Regional Wetland
Plant List (USAC 2017). A species indicator status refers to the relative frequency with which the species
occurs in jurisdictional wetlands (Appendix E). An area satisfies the hydrophytic vegetation criteria when,
under normal circumstances, more than 50 percent of the dominant species from each stratum are
obligate wetland (OBL), facultative wetland (FACW), or facultative (FAC) species.
3.2.4 Growing Season
The growing season is generally defined as the portion of the year when soil temperatures at approximately
20 inches below the soil surface are above biological zero or 5 degrees Celsius (US Department of Agriculture
Soil Conservation Service 1985). When soil temperature data are not available, the Wetland Delineation
Manual allows using the closest and best available weather station data to estimate the length of the growing
season based on a 50% probability of a temperature of 28°F or higher (Environmental Laboratory 1987,
USACE 2010). Using this approximation, the growing season in this region would be approximately 305 days
long at least 50% of the time. Generally, this translates to the period of mid-February to mid-December. To
meet the hydrology criteria at this site, soils would need to be saturated to the surface for at least 14
consecutive days during that interval. The site visits occurred at the very end of the growing season.
3.2.5 Climate
King County has a predominantly temperate marine climate typical of much of the Puget Sound area. The
property is in the Puget Sound lowlands climatic region. Summers are warm and relatively dry, and winters
tend to be mild, but rather wet. Mean high temperatures for the Seattle Tacoma Airport (4.2miles west) range
from 46°F in December and January to 76°F in July and August. Mean low temperatures range from 36°F in
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
5
April 2018
PBS Project No. 41482.000
December and January to 56°F in July and August (US Climate Normals 1912-2016). The wetland delineation
occurred on December 13, 2017. Precipitation in the spring of 2017 was well above the normal range but this
was followed by a very dry summer. The rainfall for the 6-month interval prior to the delineation was within
the normal range. Precipitation levels are considered normal when the probability of that rainfall amount for a
given month is greater than or equal to 30% either side of the mean, as displayed in the table below (Table 1).
While precipitation in October and November was slightly above normal, precipitation for the interval of June
through September was well below normal. There was 1.2 inches of rain for the 2 weeks in December prior to
the delineation, which is somewhat low for that period.
Table 1. Monthly precipitation in inches and “normal” ranges and averages for the Seattle Tacoma Airport, WA
Month Seattle, WA
2017
Seattle Tacoma Airport, WA 1970-
2016
Above or
Below
Normal 30% chance will have Average Less than More than
June 1.52 0.91 1.79 1.48 -
July T 0.34 0.85 0.70 Below
August 0.02 0.35 1.24 1.06 Below
September 0.59 0.71 2.00 1.70 Below
October 4.80 2.16 4.36 3.60 Above
November 8.63 4.10 7.02 5.90 Above
Total 14.04 8.57 17.26 14.44 Normal
3.3 Delineation Results
One wetland (Wetland A) was mapped at the eastern edge of the property in a linear depression mostly within
the WSDOT right-of-way. There is approximately 0.06 acres of wetland that extends onto the Walker property.
This wetland had been mapped by WSDOT in 2004 and verified by PBS in 2007. More recent delineation and
verification occurred in 2014/2015 as part of the WDOT direct connector project. The PBS mapped boundary
was similar to the WSDOT previously mapped boundaries. One data plot was taken in the wetland (Plot 1)
and one in the adjacent upland (Plot 2). Upland areas had no vegetation, fill material lacking hydric soil
indicators, and no wetland hydrology. The upland/wetland boundary was identified primarily on the basis of
wetland hydrology, hydric soil indicators and topography. The data sheets can be found in Appendix A.
PBS also examined other areas of the property to make sure no other wetlands were present. A small
stormwater pond is present in the southwest corner that was operational until very recently. Wetland
vegetation in the form of willows and reed canary grass is present along the edge of this constructed pond.
Soils are highly disturbed. It is PBS’s best professional judgement that this pond is not a jurisdictional wetland,
having been constructed in fill about six years ago. Shallow ponding was also observed north of the
stormwater pond in an area with highly compacted gravel soils and pavement and no vegetation. This area
did not meet the definition of a wetland.
3.3.1 Soils
Soils in Plot 1 consisted primarily of fill material. Two inches of recent wood chippings were present at the
surface. From 2 to 6 inches, the soil was sandy fill material with a matrix color of 10YR 3/2. Between 6 and 12
inches there was similar sandy, gravelly fill that had a matrix color of 2.5Y 4/1 with 2 percent redoximorphic
concentrations of 7.5YR 4/4. Below 12 inches, the matrix color remained the same with 5 percent
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
6
April 2018
PBS Project No. 41482.000
redoximorphic concentrations of 7.5YR 4/4 and 2 percent concentrations of 10YR 4/6. Some cobbles were
present at depth. The soil met the criteria for Hydric Soil Indicator F3: Depleted Matrix as defined in the Corps
of Engineers Regional Supplement. Organic soils were not found in the top 18 inches at the plot but appeared
to be present further into the wetland. The corresponding upland soil at Plot 2 was sandy gravelly fill material
that also had a matrix value of 10YR 3/2 to a depth of 10 inches with matrix colors of 10YR 4/2 and 10YR 4/1
below but no redoximorphic concentrations in the top 16 inches.
Well logs from the two wells closest to the wetland did not have information on the surface soils but found
moist silts and sandy soils at a depth of 5 feet. No organic soils were documented in the logs, which if
historically present, were probably above 5 feet in depth. Unfortunately, the logs were not useful in trying to
determine the depth of fill on the property.
3.3.2 Hydrology
Wetland hydrology was present in the form of inundation up to 2 feet in depth, water in the soil test pits near
the surface, and saturation. No detectable flow was observed. At the time of the site visit, no flow was
observed coming into the wetland from the culvert under SR 167. Some minor surface flow was detected from
the property into the wetland in the northeast corner. Hydrologic inputs appear to be primarily from high
groundwater and direct precipitation.
3.3.3 Vegetation
Stumps of black cottonwood and Pacific willow were observed in the wetland along with remnants of Douglas
spirea, red-osier dogwood and what appears to be Sitka willow (Salix sitchensis). Himalayan blackberry was
also present. Reed canary grass had about 20 percent coverage in the wetland. Wetland vegetation on the
property to the north consisted of an overstory of black cottonwood, and a shrub layer of red-osier dogwood,
willows, Douglas spirea and Himalayan blackberry. Reed canary grass dominated the understory with some
common sedge (Carex obnupta) and horsetails. Adjacent upland vegetation also had a canopy of black
cottonwood with an understory of Himalayan blackberry, reed canary grass and tansy ragwort (Senecio
jacobaea) with an occasional sword fern (Polystichum munitum). The wetland on the property to the south was
dominated by willows and reed canary grass with the wetland sandwiched between the retaining wall to the
east and a steep fill slope to the west. As mentioned previously no vegetation was present on the subject
property west of the wetland.
.
3.4 Wetland Rating and Buffers
The wetland was rated using the 2014 version of the Washington State Wetland Rating System for Western
Washington (Hruby, 2014) as a Category III wetland. Despite the fact that the wetland was once part of the
larger Panther Creek wetland to the east, it is now effectively separated and was considered a separate
wetland for the purposes of rating. The culvert under SR 167 at the property is 180 feet long and at an
elevation that it would only engage during very high water levels. Table 2 lists the characteristics of the
wetland. Figure 5 shows the wetland boundary, data plot locations and buffers. City of Renton buffers for
Category III wetlands with a habitat score of 5 to 7 are 100 feet. The wetland rates relatively high for water
quality because of the urban setting and poor water quality in the vicinity, moderate for hydrology functions,
and moderately low for habitat functions.
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
7
April 2018
PBS Project No. 41482.000
Table 2. Waters/wetlands characteristics
Characteristic Wetland A
Cowardin Classification Palustrine Forested / Scrub-Shrub
Size –(Acres) ~ 3 acres
HGM Classes Depression
WA State Wetland Rating Scores
Water Quality 8
Hydrology 6
Habitat 5
Total Score 19
Wetland Category Based on Score III
Special Characteristics Category N/A
City of Renton Buffers 100 ft
Additional Building Setback 15 ft
3.5 Regulatory Framework
Wetland A is assumed to be under Federal, State and City of Renton jurisdiction. Impacts to the wetland
would trigger both a City of Renton permit and a federal Army Corps of Engineers permit and review by other
agencies. Impacts to buffers are regulated only at the local level. The City of Renton allows buffers to be
reduced by 25 percent if the development follows certain mitigation measures which include:
• The reduced buffer will function at a higher level than the standard buffer, and
• The buffer has less than fifteen percent slopes and no direct or indirect, short-term or long-term,
adverse impacts to regulated wetlands, and
• The proposal shall rely on a site-specific evaluation and documentation of buffer adequacy based
upon the document “Wetlands in Washington State” (Ecology Publication No. 04-06-008, April 2005)
or similar approaches, and
• The proposed buffer standard is based on consideration of the best available science.
4 IMPACT ASSESSMENT
All trees and most shrubs were cleared from Wetland A between the north and south property corners east to
the SR 167 retaining wall on the WSDOT right-of-way. Clearing occurred over approximately 19,000 square
feet (0.44 acres). All but approximately 2,500 square feet of wetland clearing occurred on the WSDOT right-of-
way. Some of the logs were left in the wetland and other material was either piled in uplands or chipped on
site. Aside from some wood chips, it did not appear that any grading or filling had occurred in the wetland,
though this was difficult to determine accurately since we had not seen the site prior to disturbance and water
levels in the wetland at the time of the site visit were high enough to obscure ground disturbance. It is likely
that operation of equipment in or adjacent to the wetland caused some ground disturbance, though
fortunately the clearing occurred at the end of an extended dry period when most of the wetland was dry. At
least a dozen trees greater than 6 inches diameter were removed. Some of the stumps appeared to have been
ground down to the soil surface. Because soil disturbance appears to have been limited, herbaceous
vegetation is already starting to recover and many of the trees and shrubs are expected to re-sprout from root
crowns.
Several wetland functions have been impacted by the clearing. Despite the urban and industrialized context of
the site, the wetland performs some important wetland functions. The ability of the wetland to provide water
quality functions has been diminished by the loss of vegetation. The loss of vegetation structure has also
greatly reduced habitat functions. The narrow strip of forest and shrubs provided a corridor for wildlife in a
heavily developed landscape. The cover provided by vegetation is now gone, effectively breaking the corridor.
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
8
April 2018
PBS Project No. 41482.000
5 RESTORATION PLAN
5.1 Goals and Objectives
Mr. Walker is working with WSDOT on restoration of the wetland in the WSDOT right-of-way. The restoration
will be completed per WSDOT specifications either by WSDOT or by Mr. Walker under WSDOT supervision.
The goal of the restoration plan for the buffer will be to create a functioning buffer that protects and
enhances the wetland functions through planting and control of invasives. Nearly the entire buffer was being
used for junk vehicle storage with little to no native vegetation present. We are proposing a reduction in the
standard buffer from 100 feet to 75 feet through enhancement of the remaining buffer to include planting of
native trees, shrubs and understory vegetation. Some of the surface fill soils will be removed as part of the site
clean-up effort. Placement of compost will help improve surface soil conditions and protect water quality in
the wetland.
5.2 Performance Standards
5.2
Table 3 shows the performance standards that will be used to measure restoration success in the buffer.
Table 3. Performance Standards Thresholds
Parameter Year 1 Year 3 Year 5
Survival of planted trees 90% 80% 70%
Survival of planted shrubs/ferns 90% 80% 70%
Plant diversity - # of native species >6 >6 >6
Percent cover invasives1 < 10%
1. Invasives include Japanese knotweed, Himalayan blackberry, and any other species listed on the King County
noxious weed list. Reed canary grass is ubiquitous in this area and control is likely not feasible.
5.3 Restoration Activities
5.3.1 Fill Removal/ Grading/ Site Preparation
Per WSDOT Standard Specifications 8-02.3(2), a Roadside Work Plan, Weed and Pest Control Plan and Plant
Establishment Plan will be submitted to WSDOT prior to work. Plant establishment plan will include
requirements outlined in 8-02.3(13). Within the 75-foot buffer some contaminated fill material will likely be
removed as part of the site clean-up effort. Clean soil backfill may be placed as necessary depending on the
depth of the removal. The final buffer area will be graded to provide some microtopographic relief. Large
wood may be placed near the wetland edge for habitat improvement. Three inches of compost and three
inches of bark or wood chip mulch will be placed within the wetland boundary in areas of heavy Reed Canary
Grass infestation. No compost or bark mulch will be placed where native herbaceous plants are present. Two
inches of compost will be spread throughout the wetland buffer area to improve soil conditions. If soils are or
become compacted from construction activity, soil decompaction to a depth of 18 inches will be required
such that a soil penetrometer can be inserted to a 12-inch depth with no more than 200 PSI of pressure using
a ½-inch tip. Soil decompaction work shall be scheduled between May 1 and September 30. Weed control
shall be performed in accordance with WSDOT Standard Specifications 8-02.3(3) and 8-02.3(3)A.
5.3.2 Native Plantings
The restoration area has been divided into three planting zones. Zone A is the WSDOT wetland area that is will
be restored per WSDOT requirements. Zone B is the wetland edge that is rarely inundated, and Zone C is the
buffer zone. Zone B will be seeded with a wetland seed mix. Zone C will be seeded with an upland erosion
Formatted: Heading 2
Formatted: No bullets or numbering
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
9
April 2018
PBS Project No. 41482.000
control mix. Tabble 4 is the planting plan and Figure 5 shows the planting zones. Planting will occur in the
fallspring of 2018. Planting of Zone A may need to be delayed until water levels have come down far enough
to allow access by the planting crews. Planting in WSDOT ROW shall occur during planting window per 8-
02.3(8), October 1 – March 1.
5.3.3 Follow-up Weed Control
Himalayan blackberry will be removed throughout the wetland and buffer area where present. Other species
that will be removed if they appear in the restoration area include scotch broom, tansy ragwort, thistles, and
any other species on the King County noxious weed list. Reed canary grass is currently present it the wetland
and may spread into the buffer. Best eEfforts will be made to control the grass, but success of the restoration
will not be dependent on control of this species.
Table 4. Planting Plan for the Walker Property. All of Zone A and a third of Zone B is on WSDOT right-of-way.
The planting plan for the WSDOT areas are currently under review and subject to change.
Common Name Scientific Name Strata Number Size Spacing
Zone A –Seasonally Inundated Wetland (12,200 sq ft, 0.28 acres) Entirely on WSDOT ROW
Pacific willow Salix lucida ssp lasiandra T 20 2 gal or stake 6 to 8 feet apart Sitka willow Salix sitchensis ST 40 2 gal. or stake
Black twinberry Lonicera involucrata S 40 1 gal. pot or
bareroot 12”
min. height
randomize and avoid
disturbing native
volunteers
Red-osier dogwood Cornus sericea S 40
Douglas spirea Spirea douglasii S 40
Subtotal 180
Zone B –Wetland Edge (8,400sq ft, 0.19 acres) 3,000 sf on WSDOT ROW
Western red-cedar Thuja plicata T 8 2 or 5 gal. 6 to 8 feet apart
avoiding stumps and
live shrubs
Red alder Alnus rubra T 18 2 gal. or stake
Sitka willow Salix sitchensis ST 18 2 gal. or stake
Crabapple Malus fusca ST 16 2 gal >12’ spacing
Cluster rose Rosa pisocarpa S 30
1 gal Randomize in groups
of 3 or 4 Red-osier dogwood Cornus sericea S 30
Douglas spirea Spirea douglasii S 30
Subtotal 150
Zone B– Wetland seed mix (8,400 sq ft, 0.19 acres)
3000 sf on WSDOT ROW
Sunmark “Marsh” seed mix or equivalent
Common rush Juncus effusus H 10%
Small-fruited bullrush Scirpus microcarpus H 25%
Slough sedge Carex obnupta H 15%
Awlfruit sedge Carex stipata H 20%
Common spikerush Eleocharis palustris H 10%
Fowl managrass Glyceria striata H 20%
5 lb
Zone C – Buffer (32,000 sq ft, 0.73 acres)
Western red cedar Thuja plicata T 10 2 or 5 gal
Approx. 12 ft spacing
As shown on plans
Douglas-fir Pseudotsuga menziesii T 15 2 or 5 gal
Red alder Alnus rubra T 10 1 or 2 gal
Bitter cherry Prunus emarginata T 10 2 gal
Beaked hazelnut Corylus cornuta ST 15 2 gal.
Vine maple Acer circinatum ST 20 2 gal.
Nootka rose Rosa nutkana S 40 1 gal.
Snowberry Symphoricarpos albus S 40 1 gal.
Formatted: Font:
Formatted: Normal
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
10
April 2018
PBS Project No. 41482.000
Common Name Scientific Name Strata Number Size Spacing
Low Oregon grape Berberis nervosa S 40 1 gal. Randomize in groups
of 3 or 4 – at least 3’
spacing, 6’ from trees
Swordfern Polystichum munitum F 50 1 gal >3’ spacing
Subtotal 250
Zone C– Upland seed mix (32,000 sq ft, 0.78acres)
Blue wild rye Elymus glaucus H 30%
Native red fescue Festuca rubra H 30%
Tufted hairgrass Deschampsia cespitosa H 20%
Meadow barley Hordeum brachyantherum H 20%
30lbs
TOTAL AREA = 1.2 acres TOTAL PLANTS 580
Strata: H=herbaceous, F=fern, S=shrub, ST=small tree, T=tree
5.4 Maintenance and Monitoring of Restoration
Per City of Renton Code, the restoration plantings must be monitoring annually for 3 to 5 years or until
performance standards have been met. We are proposing a baseline monitoring, yearly monitoring in years
1,2 and 3 and then a final monitoring in Year 5 if needed. Monitoring may need to be continued beyond 5
years if performance standards are not being met. Once planting is complete, a Baseline Monitoring Report
will be submitted to the City that includes an as-built drawing and a more detailed Monitoring Plan. The as-
built report will document any grading and site preparation activities, as well as the new plantings. Specific
monitoring protocol will be provided in the Baseline Monitoring Report. Once approved by the City, this plan
will form the basis for evaluating the success of the critical area restoration. During the first two years, all
planted stock will be replaced either in kind or with another approved native species if diseased, dead or
dying. Weeding and removal of invasives will need to occur at least twice a year during the monitoring period.
Native volunteers will not be removed.
Monitoring will occur near the end of the growing season to document vigor and survival of planted stock.
Reports will be due to the City before the end of each calendar year in Years 1, 2, 3, and 5. The monitoring
report will include the following basic information:
• A tally of planted trees and shrubs in each plot to identify mortality or poor vigor.
• Estimates of native species cover by species
• Vigor and mortality of planted stock
• Percent cover of invasive weed species
• Assessment of other non-natives to determine if control is needed
• Photographs at established photo points
• Recommended contingency measures to replace mortality or control weeds.
• Observations on the overall status of the restoration area and any unauthorized activities.
A total of 6 10-foot radius circular plots will be established throughout the buffer restoration to evaluate
percent cover. The plot centers will be marked with a piece of rebar and flagging. Figure 6 shows approximate
locations of photo points and plots. The locations may be modified during baseline monitoring. Monitoring of
the WSDOT property will be done for a 3-year period according to WSDOT specifications. Once Completion of
Initial Planting has been granted per 8-02.3(12), site reviews every 2-3 months will be required at a minimum
with Contractor and WSDOT Engineer and Inspector.
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
11
April 2018
PBS Project No. 41482.000
5.5 Contingency Measures
o Contingency measures will be triggered if the performance standard thresholds are not being
met as documented during the yearly monitoring. All planted stock mortality in the first year
will be replaced either in-kind or with a replacement species approved by the wetland
biologist. Some species substitutions may be needed if the original species is not performing
well. Any replacement plantings will occur either in the fall or spring. Additional weed control
will be triggered if invasive species become established that threaten the success of the
restoration. Weed control shall be performed in accordance with WSDOT Standard
Specifications 8-02.3(3) and 8-02.3(3)A. Best efforts will be made to cControl encroachment of
Rof reed Ccanary grass from the wetland north and south of the planting area. will be limited
due to difficulty of control.
Formatted: Normal, Bulleted + Level: 2 + Aligned at: 0.75"
+ Indent at: 1"
Formatted: Font:
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
12
April 2018
PBS Project No. 41482.000
6 REFERENCES
Anchor Environmental, LLC. 2007. I-405, Tukwila to Renton Improvement Project Wetland Biology Report.
Prepared for WA Dept of Transportation, Urban Corridors Office.
Blaine Tech Services. 2017. Well Monitoring Data. 3400 E. Valley Rd., Renton, WA.
Code Publishing Co. 2017. City of Renton Municipal Code. Accessed online at:
http://www.codepublishing.com/WA/Renton/#!/Renton04/Renton0403/Renton0403050.html#4-3-050
Cowardin, L.M., Carter, V., Golet, F.C., and La Roe, E.T. 1979. Classification of Wetlands and Deepwater Habitats
of the United States. FWS/OBS79/31. US Fish and Wildlife Service, Office of Biological Services,
Washington, D.C.
DOWL Surveying. 2017. Monitoring Well Survey. 3400 East Valley Road, Renton. WA.
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y-87-1.
U.S. Department of the Army, Corps of Engineers, Waterways Experiment Station, Vicksburg, Mississippi.
Google Earth. 2017. Online aerial photographs.
Hruby, T. 2014. Washington State Wetland Rating System for Western Washington: 2014 Update. Washington
State Department of Ecology Publication # 14-06-029. Olympia, Washington.
Kane Environmental, Inc. 2017. Figure 1. Groundwater Elevation Contours, from report titled: Phase II
Environmental Site Assessment, 3400 East Valley Road, Renton, WA.
Kane Environmental, Inc. 08/2017. Soil Boring Logs. 3400 E. Valley Road.
King County IMAP. 2017. Accessed online at: http://www.kingcounty.gov/operations/GIS/Maps/iMAP.aspx
Lichvar, R.W., D.L. Banks, W.N. Kirchner, and N.C. Melvin. 2016. The National Wetland Plant List: 2016 wetland
ratings. Phytoneuron 2016-30: 1-17. Published 28 April 2016. ISSN 2153 733X
Munsell Color. 2000. Munsell soil color charts. Gretagmacbeth, New Windsor, New York.
NRCS Web Soil Survey. 2017. Accessed on-line at:
http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx
Pojar J. and A. MacKinnon. 2004. Plants of the Pacific Northwest Coast - Revised. Lonepine Publishing
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 Corps of Engineer Research and Development Center.
US Department of Agriculture, Natural Resource Conservation Service. 2017. Regional climatic data, WETS.
Accessed online at: http://agacis.rcc-acis.org/?fips=53033
USDA Natural Resources Conservation Service. 2017. Plants National Database. Accessed online at:
http://plants.usda.gov/java/
US Fish & Wildlife Service. 2017 National Wetlands Inventory. Accessed online at:
https://www.fws.gov/wetlands/Data/Mapper.html
WA State Department of Ecology. 2014. Reissuance of Coverage under the Industrial Stormwater General
Permit. WAR000021
Dale Walker Property Critical Areas Report
3400 E. Valley Rd
Renton, Washington
13
April 2018
PBS Project No. 41482.000
WA State Department of Ecology. 2017. WA State Water Quality Atlas. Accessed online at:
WA Department of Fish and Wildlife (WDFW). 2017.Priority Habitats and Species on the Web. Accessed online
at: http://apps.wdfw.wa.gov/phsontheweb/
WA State Department of Transportation (WSDOT). 2015. I-405 / SR 167 Interchange Direct Connector Project.
Request for Proposal Appendix P5: Critical Area Variance. Accessed online at:
ftp://ftp.wsdot.wa.gov/contracts/8811-SR167InterchangeDirectConnector/ConformedRFP
/AppendicesConformed/P/P05_CriticalAreaVariance/CriticalAreaPermit_LUA15-000522.pdf
WSDOT. 2015. Corps of Engineers Permit NWS-2014-29 JARPA Drawings: Sheet 2 of 20.
WSDOT. 2017. Email from Linda Cooley dated 10/18/17 regarding unauthorized clearing of WSDOT right-of-
way.
WTU Herbarium Image Collection. 2017. Burke Museum of Natural History and Culture. Accessed online at:
http://biology.burke.washington.edu/herbarium/imagecollection.php
PHOTOGRAPHS
Photo 1. Google Earth aerial of property taken in early 2017 prior to removal of vehicles and clearing.
Photo 2. Google Earth street view looking southwest from the west edge of SR 167 showing trees in
wetland prior to clearing.
N
Stormwater pond
Oyster shell pit
Ditch
Wetland
Photo 3. WSDOT photo looking north taken on
October 18, 2017 shortly after clearing. Note very
little ponding in wetland.
Photo 4. View to southeast showing water levels
in cleared area in December.
Photo 5. Buffer area just north of property. Photo 6. View of wetland on the property just
north of the subject property.
Photo 7. Wetland just south of property. Photo 8. View to north of wetland showing
current condition of wetland with WSDOT
retaining wall to the right.
Photo 9. Closeup of wetland with WSDOT
retaining wall in background.
Photo 10. Stumps and logs in wetland.
Photo 11. View to west of cleared yard and
slash/trash piles.
Photo 12. Wetland soil pit.
Photo 13. South end of wetland on property with
steep gradient at edge of fill
Photo 14. View to north of stormwater pond with
willows growing along edge. Water is no longer
being pumped and water is ponded outside of
edges of pond.
Photo 15. View to north of water ponded near
the west edge in area of compact gravel and
pavement
Photo 16. Remnants of ditch that ran west to east
across the center of the site.
FIGURES
PROJECT VICINITY MAP
Dale Walker Property
Renton, WA
FIGURE
1 PROJECT #
41482
DATE
APRIL 2018
Project Site
N
CITY OF RENTON WATERS / WETLANDS
Dale Walker Property
Renton, WA
FIGURE
2 PROJECT #
41482
DATE
APRIL 2018
Project Site
N
NATIONAL WETLAND INVENTORY
Dale Walker Property
Renton, WA
FIGURE
3 PROJECT #
41482
DATE
APRIL 2018
Project Site
N
WETLAND DELINEATION MAP
Dale Walker Property
Renton, WA
FIGURE
4 PROJECT #
41482
DATE
APRIL 2018
20
20
Proposed
75’ reduced
buffer
KEY:
Property boundary
City of Renton mapped wetlands
10’ elevation contours
PBS mapped wetland on property
Proposed 75’ reduced buffer line
Wetland Data Plot 1
Upland Data Plot 2
180’ culvert
SR
167
Project Site
N
Wetland A
RESTORATION PLANTING PLAN
Dale Walker Property
Renton, WA
FIGURE
5 PROJECT #
41482
DATE
APRIL 2018
SR 167
KEY:
Wetland Boundary
Property boundary
Zone A – Seasonally Inundated
Zone B – Wetland edge
Zone C – 75’ Buffer Plantings
Habitat Logs 0 25 50
Approximate Scale
A
B
C
Proposed
75’ Buffer
N
SR 167
Planting on WSDOT right-of-
way will be undertaken per
WSDOT specifications either
by WSDOT or under WSDOT
supervision
KEY:
Property boundary
Zone A – Seasonally Inundated
Zone B – Wetland edge
Zone C – 75’ Buffer Plantings
Habitat Logs
Monitoring Plots
Photo Points
RESTORATION MONITORING PLAN
Dale Walker Property
Renton, WA
FIGURE
6 PROJECT #
41482
DATE
APRIL 2018
SR 167
1
1
1
2
3
4
6
1
Proposed
75’ Buffer
A
B
C
N
0 25 50
Approximate Scale
7
1 5
8
This figure shows
monitoring on the Walker
property only. WSDOT will
coordinate monitoring on
their property.
APPENDIX A
Wetland Delineation Datasheets
APPENDIX B
Wetland Rating Forms