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Home My WebLink AboutRS_Critical Areas Report_191031_v1.pdfMarch 22, 2018 ADF Properties, LLC 15007 Woodinville Redmond Road, Suite A Woodinville, Washington 98072 RE: Sunset Highlands Critical Areas Report – Parcel # 0323059093 SWC Job #18-108 This report describes our observations of any jurisdictional wetlands, streams and buffers on or within 200’ of Parcel # 0323059093, located off NE Sunset Way, in the City of Renton, Washington (the “site”). Above: King County iMap of site Specifically, the site is a 0.81 acre irregular shaped parcel located in the SW ¼ of Section 3, Township 23 North, Range 5 East of the Willamette meridian in King County Washington. Sewall Wetland Consulting, Inc. Po Box 880 Phone: 253-859-0515 Fall City, WA 98024 ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 2 METHODOLOGY Ed Sewall of Sewall Wetland Consulting, Inc. inspected the site on February 20, 2018. The site was previously delineated by Sewall Wetland Consulting on May 17, 2007. The site was reviewed using methodology described in the Washington State Wetlands Identification Manual (WADOE, March 1997). This is the methodology currently recognized by the City of Renton and the State of Washington for wetland determinations and delineations. The site was also inspected using the methodology described in the Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987), and the Western Mountains, Valleys and Coast region Supplement (Version 2.0) dated June 24, 2010, as required by the US Army Corps of Engineers. Soil colors were identified using the 1990 Edited and Revised Edition of the Munsell Soil Color Charts (Kollmorgen Instruments Corp. 1990). ] ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 3 Soil colors were identified using the 1990 Edited and Revised Edition of the Munsell Soil Color Charts (Kollmorgen Instruments Corp. 1990). OBSERVATIONS Existing Site Documentation. Prior to visiting the site, a review of several natural resource inventory maps was conducted. Resources reviewed included the National Wetland Inventory Map, WADNR Fpars, and the NRCS Soil Survey online mapping and Data. Soil Survey According to the King County Soil Survey, the soils onsite are completely comprised of the Ragnar Indianola soil association, sloping (RDC). Ragnar soils are not considered to be hydric (wetland) soils, according to the publication Hydric Soils of the United States (USDA NTCHS Pub No.1491, 1991). Above: USDA Soil Survey Map of the site National Wetlands Inventory (NWI) According to the NWI map for the site there are no wetlands on or near the site. ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 4 Above: National Wetlands Inventory Map of the site. WADNR Fpars Stream Mapping The Washington Department of Natural Resources Fpars stream type mapping website depicts no streams on or near the site. ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 5 Above: WADNR Fpars stream mapping City of Renton Water Resource Map The US Fish and Wildlife online wetland mapper and the Department of Natural Resources FPARS maps do not show any wetlands or streams located onsite. However, there is a non-fish bearing portion of Honey Dew Creek mapped offsite to the northeast. According to the City of Renton flood hazard and wetlands maps, there are no known flood hazards or wetlands within 100-feet of the site (Figures 4-3-050Q2 and 4-3-050Q5). The City of Renton Water Class Map in RMC 4-3-050Q4 shows Honey Dew Creek extending across NE Sunset Boulevard, at which point it becomes a Class 4 stream, and then entering the site. City of Renton Water Class Map ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 6 Sewall Wetland Consulting, Critical Areas Study Sunset Property November 7, 2007 Our company prepared a critical areas study and restoration plan for the stream buffer in November of 2007. At that time, a Type 4 stream was found along the south edge of the site. This is a ditched upper portion of Honey Dew Creek. At that time this stream had a 35’ buffer which was reduced to 25’ with enhancement and a split rail fence. The mitigation area was installed and initially monitored until transient use of the site destroyed and eliminated much of the plantings in the area. Above: Previously approved mitigation plan sections showing stream and 25’ buffer. Field observations Uplands The site is generally devoid of vegetation as the blackberry and giant knotweed thicket that was a transient encampment has been kept mowed down. The only existing vegetation is along the property boundaries and along the stream at the southern end of the property. Dominant vegetation within the vegetated uplands included red alder ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 7 (Alnus rubra), Japanese knotweed (Polyganum cuspidatum), and Himalayan blackberry (Rubus armeniacus). Soils within the uplands generally revealed a compact 16-inch gravelly sandy loam layer with a color of 10YR 3/3. Soils within the uplands were dry at the time of our May 17th site visit. Wetlands No areas meeting wetland criteria are found on the site. Streams A ditched stream, identified as Stream A, flows eastward across the southeast property corner of the site between two culverts. Stream A was flagged with white with blue dot boundary flagging labeled A1 though A8 on the north ordinary high water mark (OHWM) and AA1 through AA8 on the south OHWM. The onsite section of the stream is assumed to be part of the mapped Honey Dew Creek, as previously described. The City of Renton Aquifer protection map (RMC Figure 4-3-050Q1) shows that this stream flows subsurface within a pipe from the north side of NE Sunset Boulevard onto the site, surfaces across the site, and then exits via a second culvert which discharges at the west side of Duvall Avenue NE, approximately 1000-feet to the east of the site. The banks of the ditch and associated stream buffers contain forested and scrub-shrub vegetative communities. Dominant vegetation adjacent to the stream includes red alder (Alnus rubra), Himalayan blackberry (Rubus armeniacus), and giant knotweed (Polyganum cupsodatum). Stream A has an average channel with of approximately 2 -feet and an average depth of approximately 12-inches. At the time of site visit, the channel contained flowing water approximately 8-inches deep. The stream bed was unconsolidated and comprised of a mixture of sand and gravel. Due to the long distances in which this stream is located within subsurface pipes, the segmented portion of stream and stream buffer located onsite provide very little hydrologic or ecologic function. The site ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 8 is totally surrounded by urban development, and no evidence of wildlife presence was observed onsite during our field visit. Stream A would be considered a Type Ns stream, due to lack of fish use and season flow. Typically, Type Ns streams have a 50’ buffer as well as a 15’ building setback for structures. Proposed Project The proposed project is the construction of a multifamily apartment complex. Due to the diagonal configuration of the site forcing struct ures on an angle across the site, as well as the fact the buffer was a previously fenced 25’ area and now includes a degraded area, a reduced buffer is proposed. Under RMC 44-3-050-I.1, Type Ns streams can have their buffer reduced to 40’ if it meets the following criteria; a. Criteria for Reduction of Degraded Stream Buffer Width with Enhancement: A reduced buffer will be approved in a degraded stream buffer only if: i. It will provide an overall improvement in water quality; and Response: Removal of existing trash and use by transients will greatly improve water quality. Planting with native trees and shrubs will help filter any runoff and improve stream function. ii. It will provide an overall enhancement to fish, wildlife, or their habitat; and Response: The reduced and enhanced buffer will improve water quality and shading of the stream, which will improve overall functions of the stream. Removal of transients and trash will greatly improve water quality and create a safe habitat area that doesn’t exist today. ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 9 iii. It will provide a net improvement in drainage and/or stormwater detention capabilities; and Response: The proposed reduced buffer and site stormwater facilities will improve stormwater functions of the site. iv. It will not be materially detrimental to any other property or the City as a whole; and Response: The proposed reduced buffer will not be detrimental to any property and will be an improvement over current heavily degraded conditions. v. It will provide all exposed areas with stabilized native vegetation, as appropriate; and Response: The proposed enhancement of the reduced buffer will stabilize the buffer with native vegetation. vi. The request is not made in conjunction with buffer reduction, an vii. It will provide, as part of the buffer reduction request, buffer enhancement plan prepared by a qualified professional and fund a review o f the plan by the City’s consultant. The plan shall assess habitat, water quality, stormwater detention, groundwater recharge, shoreline protection, and erosion protection functions of the buffer; assess the effects of the proposed modification on those fu nctions; and address the six (6) criteria listed above. Response: A stream buffer enhancement plan will be provided to the City as required after this reduction request is approved. The impacted buffer area for the structure will be averaged as shown on the plan. ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 10 If you have any questions in regards to this report or need additional information, please feel free to contact me at (253) 859-0515 or at esewall@sewallwc.com . Sincerely, Sewall Wetland Consulting, Inc. Ed Sewall Senior Wetlands Ecologist PWS #212 ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 11 REFERENCES Cowardin, L., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, FWS/OBS-79-31, Washington, D. C. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1. U. S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi. Muller-Dombois, D. and H. Ellenberg. 1974. Aims and Methods of Vegetation Ecology. John Wiley & Sons, Inc. New York, New York. Munsell Color. 1988. Munsell Soil Color Charts. Kollmorgen Instruments Corp., Baltimore, Maryland. National Technical Committee for Hydric Soils. 1991. Hydric Soils of the United States. USDA Misc. Publ. No. 1491. Reed, P., Jr. 1988. National List of Plant Species that Occur in Wetlands: Northwest (Region 9). 1988. U. S. Fish and Wildlife Service, Inland Freshwater Ecology Section, St. Petersburg, Florida. Reed, P.B. Jr. 1993. 1993 Supplement to the list of plant species that occur in wetlands: Northwest (Region 9). USFWS supplement to Biol. Rpt. 88(26.9) May 1988. City of Renton Code USDA NRCS & National Technical Committee for Hydric Soils, September 1995. Field Indicators of Hydric Soils in the United States - Version 2.1 ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 12 Above and below: stream as it passes through the site. ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 13 Above and below: Looking north across the site. ADF/#18-108 Sewall Wetland Consulting, Inc. March 22, 2018 Page 14 Above and below: Stream as it passes off -site to the west 14"FIR 16"FIR 24"FIR 12"FIR 20"FIR 16"FIR 30"FIR 16"FIR 303.5 L F ROCK E R Y ROCK E R Y ROCKERY - - - - -5' HOG WIRE FENCE6' CY C L O N E F E N C E LS PV LS LS LS - SIDE W A L K 48" P o pl a r 24" CEDAR 30" Fir 18" MAPLE 30" FIR - > SB SIGNAL BOX SB TV N63°5 7' 2 7 " E 1423. 1 4' ( M ) 1423. 2 1' ( S T) 595.0 7' ( C ) 595.1 0' ( S T)S26°02 '33 "E 45 .00 ' NE SU N S E T B L V D N0° 00' 25"E174.68'N89° 37' 58"W 164.55'S0° 15' 59"W256.71'N63° 5 7' 2 7 " E 184.4 5' 400 397 398 399 401 400 396 397 398 399 400 396397398 3 9 9 STORM CHAMBER DETENTION SYSTEMSTORM CHAMBER DETENTION SYSTEM PERVIOUS PAVERS (TYP.) PERVIOUS PAVERS (TYP.) PERVIOUS ACCESS PATH 40' BUFFER BUFFER AVERAGING IMPACTED AREA 331 SF BUFFER AVERAGING REPLACEMENT AREA 331 SF 32' 31' Civil Engineers Structural Engineers Landscape Architects Community Planners Land Surveyors Neighbors SUNSET HIGHLANDS 2140679.10