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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