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HomeMy WebLinkAboutAppx F 10-04766-018 BRPS Habitat Data Rpt 150623 HABITAT DATA REPORT BLACK RIVER PUMP STATION SEDIMENT REMOVAL PROJECT Department of Natural Resources and Parks Water and Land Resources Division HABITAT DATA REPORT Black River Pump Station Sediment Removal Project Prepared for Department of Natural Resources and Parks Water and Land Resources Division King Street Center – DNRP 201 South Jackson Street, Room 700 Seattle, Washington 98104-3855 by Herrera Environmental Consultants, Inc. 2200 Sixth Avenue, Suite 1100 Seattle, Washington 98121 Telephone: 206-441-9080 March 12, 2015 i kg 10-04766-018 brps habitat data rpt 150623.docx DISCLAIMER Herrera Environmental Consultants, Inc. has prepared this report for use by King County. The results and conclusions in this report represent the professional opinion of Herrera Environmental Consultants, Inc. They are based in part upon: (1) site evaluation, and (2) examination of public domain information concerning the study area. Various agencies of the State of Washington and local jurisdictions may require a review of final site development plans that could potentially affect zoning, buffer requirements, water quality, and/or habitat functions of lands in question. Therefore, the findings and conclusions in this report should be reviewed by appropriate regulatory agencies before any detailed site planning and/or construction activities. iii kg 10-04766-018 brps habitat data rpt 150623.docx CONTENTS Executive Summary ......................................................................................... v Introduction ................................................................................................. 1 Study Objectives ...................................................................................... 1 Project Description ................................................................................... 2 Sediment Characteristics ..................................................................... 2 Staging Area .................................................................................... 5 Sediment Excavation, Dewatering, and Treatment ....................................... 5 Methods ...................................................................................................... 7 Review of Available Information .................................................................... 7 Field Studies ........................................................................................... 7 Results ....................................................................................................... 9 Analysis of Available Information ................................................................... 9 Previously Mapped Wetlands ................................................................. 9 Previously Mapped Streams ................................................................... 9 Documented Habitat and Vegetation ...................................................... 10 Fish and Wildlife Use ......................................................................... 13 Results of Field Studies ...................................................................... 15 Wetlands ....................................................................................... 15 Streams ......................................................................................... 16 Upland Forest/Buffer ......................................................................... 16 Habitat Connectivity and Fragmentation .................................................. 17 Critical Species Associated with On-Site Habitat Types ................................. 17 Habitat Functions and Values ............................................................... 18 Regulatory Implications .................................................................................. 19 Avoidance and Minimization Measures ................................................................. 21 Project Impacts and Mitigation .......................................................................... 23 Wetland Buffers and Vegetation Clearing ........................................................ 23 Noise ................................................................................................... 23 References ................................................................................................. 25 APPENDICES Appendix A Project Area Photos iv kg 10-04766-018 brps habitat data rpt 150623.docx TABLES Table 1. Special Status Species and Habitats in the Project Vicinity. ........................... 10 Table 2. Delineated Wetlands and Streams in the Study Area. ................................... 16 FIGURES Figure 1. Study Area and Vicinity Map. ................................................................. 3 Figure 2. Critical Habitats and Species in the Study Area. ......................................... 11 v kg 10-04766-018 brps habitat data rpt 150623.docx E XECUTIVE S UMMARY The Black River Pump Station is a concrete dam spanning the Black River to control flooding in the lower Green River valley. Sediment that has accumulated behind the structure since its construction in the 1970s has become an operational concern and needs to be removed. King County, which operates the pump station, plans to dredge approximately 2,900 cubic yards of sediment from an area extending about 100 feet upstream from the station. Construction will begin in May of 2016 and will last about 4 months. Final sediment removal and site restoration may continue in the summer of 2017. The project will occur in the city of Renton. This report was prepared in accordance with Renton Municipal Code (RMC), which requires a habitat conservation assessment (Habitat Data Report) for all projects located within or having the potential to impact critical habitat (RMC 4-8-120 and 4-3-050). Project biologists used best available science to document critical habitat and wildlife in the project vicinity, assess potential impacts on those areas, and develop appropriate mitigation. Information was gathered through site visits, use of standard manuals and methods, online resources, and published and unpublished reports. The study area includes the project footprint, an area extending approximately 0.5 mile upstream of the project, and downstream of the dam to 68th Avenue South. Critical habitat within the project vicinity includes riparian, wetland, and upland habitats. Several federal- and State-listed species have been documented in the study area, and a number of other listed species have the potential to be present during project construction. Several measures have been incorporated into the project design to reduce impacts on critical habitats. Based on feedback from regulatory agencies and other interested parties, the following changes were made: • To minimize potential negative effects on water quality from increased sediments, the contractor will be required to dewater the work area using a temporary flow diversion structure (such as a coffer dam) before dredging, instead of being allowed the choice between dewatering or dredging in the wet. • To limit impacts on wetlands and a Great Blue Heron colony north and east of the Black River, sediment will be dewatered in a decant facility constructed south of the river instead of north of the river as originally planned. • Impact pile driving was eliminated as a construction method to prevent noise impacts on the heron colony as well as other wildlife. Turbidity will be controlled by the use of a cofferdam, turbidity curtains, the pump station itself, and other best management practices. Cleared areas will be restored post-project with native vegetation, ensuring no net loss of ecological function. vi kg 10-04766-018 brps habitat data rpt 150623.docx The revised project will still have unavoidable temporary impacts on critical habitats, but they will affect a smaller area. Staging area construction will clear combined stream and wetland buffer on the south side of the Black River. Most of the buffer consists of mowed lawn dominated by Kentucky bluegrass (Poa pratensis). Installation of the bypass pipe on the north side of the Black River will also have impacts on stream and wetland buffers. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 1 I NTRODUCTION The Black River Pump Station (BRPS) in Renton, Washington, was constructed in the 1970s to control flooding in the lower Green River valley. The pump station consists of a concrete structure placed across the Black River channel, approximately 1,700 feet upstream of the confluence with the Green River (Figure 1). Eight pumps within the structure control the quantity of downstream flow. Sediment that has accumulated behind the pump station since its construction has become an operational concern. King County Water and Land Resources Division, which operates the pump station, plans to dredge approximately 2,900 cubic yards of sediment from an area extending about 100 feet upstream from the station. The project is scheduled to begin construction in late May of 2016 and will last about 4 months. Construction may extend into 2017 if work cannot be completed in one season. The project is located on the western edge of the Black River Riparian Forest and Wetland (BRRFW), a 92-acre wetland complex within the Renton city limits. Renton Municipal Code (RMC) requires a habitat conservation assessment for projects located within or having the potential to impact critical habitat or wildlife (RMC 4-8-120). RMC (Sections 4-3-050 and 4-3-090) defines critical habitat as habitat areas that meet the following criteria: 1. Habitats associated with the documented presence of non-salmonid species proposed or listed by the federal government or State of Washington as endangered, threatened, candidate, sensitive, monitor, or priority; and/or 2. Category 1 wetlands. RMC defines critical wildlife species as non-salmonid species proposed or listed by the federal government or State of Washington as endangered, threatened, candidate, sensitive, monitor, or priority (RMC 4-3-050.K.1.a). The study area consists of the project footprint, an area extending approximately 1,500 feet upstream of the project footprint, and the section of the Black River extending downstream from the pump station to 68th Avenue South (Figure 1). Several federal- and State-listed species are present in the study area, as well as areas designated as Priority Habitat by the Washington Department of Fish and Wildlife (WDFW). The BRRFW contains a Category 1 wetland. Study Objectives The objective of this study is to provide the City of Renton (City) enough information to assess project impacts on critical habitat. This report: • Describes the proposed project and study area. • Identifies and maps documented critical habitats, including those identified by WDFW’s Priority Habitats and Species (PHS) database and the Washington Department of Natural Resources (WDNR) Washington Natural Heritage Program (WNHP) database. March 2015 2 Habitat Data Report—Black River Pump Station Sediment Removal Project • Identifies vegetation cover types. • Describes the characteristics, condition, function, and values of habitat areas. • Describes fish and wildlife use of habitat areas. • Summarizes project impacts and proposed impact mitigation measures. Project Description The project is located in the northwest portion of the city of Renton in King County, Washington. The specific project location is in Section 13 of Township 24 N, Range 4E. The Black River is in Water Resource Inventory Area (WRIA) 9 (Green Duwamish) and Hydrologic Unit Code 170011001303 (Lower Green River). Sediment in the Black River upstream of the dam will be removed by mechanical dredging. The work area will be isolated from the Black River and dewatered. The Black River will be pumped around the pump station, then sediment will be excavated directly from the riverbed down to the concrete forebay apron and at a 4V:1H slope to grade. Before dredging begins, a staging area will be constructed on the south side of the river for equipment, sediment stockpiling, sediment dewatering, and water quality treatment. The in-water work area will then be isolated with turbidity curtains, a temporary flow diversion structure (such as a cofferdam), and/or other best management practices (BMPs). The Black River will be routed through a bypass pipe on the north side of the river for the duration of in-water work. Pump station pumps will be used to dewater the area until water levels are too low or the water becomes too turbid, at which point portable pumps will be used to remove the remaining water. Construction equipment will then be mobilized in the work area. Sediment will be dredged, then stockpiled and dewatered in the dewatering area. Dewatering water will be discharged back into the Black River once it has been treated to meet State Surface Water Quality Standards. Dewatered sediment will be hauled off-site for disposal. Once dredging is complete, in-water BMPs will be removed and the staging area will be restored and replanted with appropriate native vegetation. Sediment Characteristics Sampling results indicate that sediments in the pump station forebay contain elevated levels of arsenic, cadmium, nickel, total petroleum hydrocarbons (TPH), bis (2-ethylhexyl) phthalate, and polychlorinated biphenyls (PCBs) (King County 2008). During dredging, the work area will be isolated using silt curtains, a cofferdam, or other BMPs to minimize the spread of contaminated sediments as much as possible. BMP installation and removal will occur when the pump station pumps are turned off, to prevent pumping turbid water downstream. A 1-foot-thick sand cap will be placed over excavated areas outside the concrete apron, and the area will be re-watered slowly once dredging is complete to minimize sediment disturbance. The dredged sediment will be disposed of at a site approved to accept these materials. Dewatered mechanical dredging. OAKES D A L E A V E S W MONSTER RD SWBlack River Riparian Forest and Wetland Black RiverPump Station MONST E R R D S W SW 7TH STDuwamishRiver GreenRiverSpringbrookCreek B l a ck R i verGreenRiverTrail-Lo w er Gr e e n River Trail- T u k w ila Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping,Aerogrid, IGN, IGP, swisstopo, and the GIS User Community Figure 1.Study Area and Vicinity Map. 0 400 800200ft Produced By: GISProject: K:\Projects\Y2010\10-04766-018\Project\Habitat_Data_Report\study_area_vicinity_11x17.mxd (1/6/2015) NAD 1983 HARNWashington State Plane North FIPS 4601 ESRI, Aerial (2011) Legend Study area Staging area In-water work zone Trail Railroad 405 5 900 169 LakeWashington 518 March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 5 Staging and Bypass Pipe Areas A staging area will be constructed on the south bank of the Black River to stage materials prior to and during construction (Figure 1). This area will include a pad to support the crane used to lift and position equipment into the work zone as well as an access road leading to the shoreline. A sediment dewatering and treatment area will also be constructed on the south bank. Staging area construction will clear vegetation with the regulatory stream buffer as well as portions of Wetland B and C buffers. The staging area will be restored to preconstruction grades prior to revegetation with appropriate native plants. The Black River will be pumped through a bypass pipe for the duration of in-water work. The pipe will run along the north bank of the river through portions of the buffer of Wetland D and the Black River. There may be some minor vegetation clearing in the bypass pipe alignment, resulting in combined Wetland D and stream buffer impacts. No woody vegetation will be cleared to lay the pipe, and cleared areas will be reseeded post project. Sediment Excavation, Dewatering, and Treatment Sediment will be excavated using dredging buckets deployed from cranes, excavators, and front loaders. Hydraulic dredging (using suction pumps to remove sediment and entrained water) may also be used to remove sediments behind the pump station’s trash racks, due to restricted access in that area. The excavated sediment may contain up to 70 percent water by volume and will need to be dewatered prior to disposal. Sediment stockpiling and decanting, and water treatment will be conducted in part of the staging area. The treatment area will be constructed using an impervious liner with a perimeter berm to contain water. Decant water will have relatively high turbidity and may have elevated levels of contaminants. Water will be treated on-site and then discharged back to the Black River. Water will likely be treated through a combination of pumping and settling in tanks, sand filtration to remove suspended solids, and, if necessary, carbon filtration to remove toxics. Drying agents may be used to speed the dewatering process. Drying agents will not be allowed to come into contact with Waters of the State. Any water discharged to the river will meet State Surface Water Quality Standards for turbidity and toxics. Water that does not meet water quality standards will be discharged to the sewer and directed to the nearby King County South Treatment Plant for treatment or hauled to a permitted disposal facility. Dewatered sediment will be disposed of at an approved, off-site permitted upland facility. Portable pumps will be used to remove any water that seeps past the cofferdam. Water will be pumped downstream of the pump station, unless it is too turbid to meet State surface water quality standards. Turbid water will be pumped directly to the on-site decant facility for treatment prior to being discharged back into the Black River. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 7 M ETHODS Review of Available Information Data on critical habitats in the project vicinity were collected using best available science, per WAC 365-195-900. Project biologists reviewed the project footprint and construction methods provided by the design team to determine the extent of potential impacts. Data sources used for this project include: • GIS base maps of the natural environment depicting the locations of aquatic resources, sensitive areas, species of interest, and existing infrastructure (USFWS 2014; King County 2014; Renton 2014a) • Records of listed species and designated critical habitat from the National Marine Fisheries Service (NMFS 2014) and US Fish and Wildlife Service (USFWS; USFWS 2014) • PHS and Species of Interest data from WDFW (WDFW 2014) • WNHP species and habitat database from WDNR (WDNR 2014a) • Water quality information from the Washington Department of Ecology (Ecology 2012) • Sediment quality information from studies conducted by King County (King County 2008) • Information summarized in reports from other recent projects in the vicinity (Parametrix 2011, 2013) • Information from project engineers regarding the project design and construction methods Field Studies Biologists visited the site on several occasions in 2014 and 2015 to conduct wildlife and habitat surveys, delineate wetlands, and delineate the ordinary high water mark (OHWM) on the Black River. Existing wetland and stream conditions are documented in the Draft Wetland and Stream Delineation Report (Herrera 2014a). Wetland and OHWM delineations were performed by Herrera biologists Julia Munger and Alicia Ward on February 21 and 24, March 19, and April 30, 2014. Wildlife and habitat surveys were conducted by Herrera biologists Alicia Ward and George Ritchotte on June 4, July 6, August 31, 2014, and January 8 and 24, 2015. Vegetation cover types were mapped using data collected during field visits and from aerial photos. The study area encompassed the project footprint, the area extending approximately 1,500 feet upstream from the pump station, and the Black River extending downstream from the pump station to 68th Avenue South (Figure 1). March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 9 R ESULTS Several special status species and associated habitats have been documented or could occur in the project vicinity (Table 1; Figure 2). Federally threatened species and critical habitat include Oregon spotted frog (Rana pretiosa) and yellow-billed cuckoo (Coccyzus americanus). A separate Biological Evaluation covering these species as well as salmonid species that are beyond the scope of this report (Chinook salmon [Oncorhynchus tshawytscha], Chinook salmon critical habitat, steelhead trout [O. mykiss], bull trout [Salvelinus confluentus]) has been prepared to address potential project impacts on species and critical habitat listed under the Endangered Species Act (ESA) (Herrera 2014b). Analysis of Available Information Due to its location on the edge of a large reserve in a largely urban area, and the presence of listed species and habitats, existing conditions in the BRRFW have been well-documented. Federal, State, and local agencies have all collected background data on wetlands, streams, and habitats in the vicinity. Previously Mapped Wetlands The National Wetlands Inventory (NWI) documents several palustrine scrub-shrub (PSS) wetlands in the BRRFW (USFWS 2014). Several wetlands were mapped in the study area as part of King County’s proposed Lake to Sound Trail (Parametrix 2011). The City identifies most of the BRRFW north of the Black River as wetland (Renton 2014a). Four wetlands were delineated in the project area in spring of 2014 (Figure 2, Herrera 2014a). Previously Mapped Streams The Black River is the only stream present in the study area. The hydrology of the Black River has been highly modified in the last century. The river used to drain Lake Washington and the Cedar River until 1912, when the Cedar River was diverted into Lake Washington to control flooding in the City. In 1916, the Black River was further modified by construction of the Lake Washington Ship Canal, which lowered the lake level and dried up the river. Today, the Black River is the name for the downstream reach of Springbrook Creek. The creek drains roughly 15,763 acres in the lower Green River basin before entering the Green River, about 1,700 feet downstream of the BRPS (Kerwin and Nelson 2000). The Black River is a perennial salmonid-bearing stream and is therefore designated by the City as a Class 1 water (RMC 4-3-050) as well as a Shoreline of the State (RMC 4-3-090). The river is listed as impaired on the State 303(d) list for fecal coliform and is listed as a water of concern for dissolved oxygen, temperature, and bis (2-ethylhexyl) phthalate (Ecology 2012). The NWI categorizes the Black River in the project area as lower perennial riverine wetland and deep water habitat, with an unconsolidated bottom that has been modified by humans (USFWS 2014). March 2015 10 Habitat Data Report—Black River Pump Station Sediment Removal Project Table 1. Special Status Species and Habitats in the Project Vicinity. Common Name Scientific Name Statusa Presence in Study Area Fish River lamprey Lampetra ayresi FCo, SC Likely to occur Amphibians and Reptiles Oregon spotted frog Rana pretiosa FT, SE Not likely to occur Western toad Anaxyrus boreas SC Not likely to occur Western pond turtle Actinemys marmorata FCo, SE Not likely to occur Birds Bald eagle Haliaeetus leucocephalus FCo, SS Documented Great blue heron Ardea herodias SM Documented Osprey Pandion haliaetus SM Documented Pileated woodpecker Dryocopus pileatus SC Documented Turkey vulture Cathartes aura SM Likely to occur Peregrine falcon Falco peregrinus FCo, SS Possible Yellow-billed cuckoo Coccyzus americanus FT, SC Not likely to occur Vaux’s swift Chaetura vauxi SC Not likely to occur Mammals Townsend’s big-eared bat Corynorhinus townsendii FCo, SC Possible Plants and Habitat Pacific pea Lathyrus vestitus SE Not likely to occur Biodiversity area and corridor NA PH Urban deciduous riparian forest with great blue heron nesting and waterfowl use. Freshwater wetlands NA PH Contains various classes of wetlands. Waterfowl concentrations NA PH Ponds provide urban wintering dabbling and diving duck habitat. a FT = Federal threatened; FPT = Federal Proposed as Threatened; FCo = Federal Species of Concern; SE = State Endangered; SC = State Candidate Species; SS = State Sensitive Species; SM = State Monitored Species; PH = Priority habitat Documented Habitat and Vegetation The study area is designated as “Natural Environment” under the Shoreline Master Program because it meets the criteria of a shoreline that retains the majority of natural shoreline functions, represents ecosystems of particular scientific and educational interest, has large areas of relatively undisturbed wetlands, and supports important wildlife habitat, such as heron rookeries (Renton 2004). WDFW lists the BRRFW as a Priority Aquatic Habitat, as well as a designated Waterfowl Concentration area, due to high numbers of waterfowl that congregate there during winter months (WDFW 2014; Figure 2). The reserve is also a Biodiversity Area and Corridor, defined as an area of habitat relatively important to various species of wildlife. OAKES D A L E A V E S W MONSTER RD SWBlack River Riparian Forest and Wetland Black RiverPump Station 330-ft 660-ft MONST E R R D S W SW 7TH STA B C D SpringbrookCreek B l a c k R i v e r Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping,Aerogrid, IGN, IGP, swisstopo, and the GIS User Community Figure 2.Critical Habitats and Species in the Study Area. 0 300 600150ft Produced By: GISProject: K:\Projects\Y2010\10-04766-018\Project\Habitat_Data_Report\critical_habitat_species_11x17.mxd (2/2/2015) NAD 1983 HARNWashington State Plane North FIPS 4601 ESRI, Aerial (2011) Legend Approximate staging area Delineated wetland Wetland buffer Wetland (WDFW PHS) In-water work zone Railroad Trail Biodiversity Areasand Corridor (BAC) Waterfowl concentration Great blue heron colony Bald eagle nest Bald eagle nest buffer March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 13 According to the Washington Natural Heritage Program (WNHP), Pacific pea (Lathyrus vestitus), a State endangered species, has been documented northwest of the BRRFW. There are no WNHP records of high-quality ecosystems in the study area (WDNR 2014a). Fish and Wildlife Use A variety of special status fish and wildlife species have been documented in the study area (Table 1). WDFW PHS data note the presence of a great blue heron colony in the BRRFW, approximately 1,200 feet east of the pump station. Two bald eagle nests are located near the project area, one approximately 1,800 feet to the east within the BRRFW and one about 2,000 feet to the northwest (Figure 2). The nest to the northwest has not been active within the past several years (WDFW 2014; C. Anderson, WDFW, personal communication to G. Ritchotte on August 25, 2014); that pair may have moved to the nest within the riparian forest. The eagle pair within the riparian forest has been observed hunting the herons at the rookery (Suzanne Krom, Herons Forever, personal communication to G. Ritchotte on December 9, 2014; Figure 2). According to WDFW (C. Anderson, personal communication to John Koon, King County, on March 10, 2008), the BRRFW is known to provide habitat for: • Various songbird species • Woodpeckers: downy, hairy, and northern flicker • Hawks and owls: Cooper’s hawk (Accipiter cooperii), red-tailed hawk (Buteo jamaicensis), barred owl (Strix varia), great-horned owl (Bubo virginianus), and western screech owl (Megascops kennicottii) • Mammals: deer mice (Peromyscus maniculatus), eastern gray squirrels (Sciurus carolinensis), beavers (Castor Canadensis), raccoons (Procyon lotor), opossums (Didelphis virginiana), coyotes (Canis latrans) river otter (Lontra canadensis), and muskrat (Ondatra zibethicus) • Reptiles and amphibians: Painted turtle (Chrysemys picta), red-eared slider (Trachemys scripta elegans), Pacific tree frog (Pseudacris regilla), long-toed salamander (Rana catesbeiana), ensatina (Ensatina eschscholtzii), and bullfrogs (Rana catesbeiana) Other critical wildlife species listed below have not been documented in the study area, but have been documented nearby or have an association with on-site habitat types: • River lamprey: River lamprey are a federal Species of Concern and a State Candidate species. They have been documented in the Duwamish River/Green River watershed downstream of the BRPS (Stober and Pierson 1984) and could potentially occur in the project area. An unidentified lamprey species was observed during in-water work on Springbrook Creek, approximately 1 mile upstream from the BRPS (G. Ritchotte, personal observation). March 2015 14 Habitat Data Report—Black River Pump Station Sediment Removal Project • Turkey vulture: Turkey vultures, a State Monitor species, have been observed in the project vicinity. This is a wide-ranging species that is likely to occur within the BRRFW. • Osprey: Osprey are a State Monitor species likely to occur in the project area. WDFW PHS data note the presence of an osprey nest approximately 1 mile south of the project footprint (WDFW 2014). The open water portion of the Black River near the pump station provides osprey foraging habitat. • Peregrine Falcon: Peregrine falcon is a federal Species of Concern and a State Sensitive species that could occur in the project area. Peregrines usually nest on cliffs, ledges, or buildings. There is no suitable nesting habitat in the project area, and the nearest known aerie is approximately 8 miles away. Peregrine hunting territories extend up to 15 miles from nesting sites (Towry 1987), so these birds could forage in the project area. • Townsend’s big-eared bat: Townsend’s big-eared bat is a federal Species of Concern and State Candidate species. These bats are found statewide. In western Washington, they forage in lowland mixed conifer-hardwood forests and riparian wetlands and use hollow trees for roosting (Woodruff and Ferguson 2005). Although no occurrences have been documented for the project area, the BRRFW provides potential foraging and roosting habitat. The following species have not been documented in the project vicinity. They could be found there, but habitat requirements or rarity of the species make their presence unlikely. • Oregon spotted frog and western toad: The BRRFW provides potential habitat for both Oregon spotted frog and western toad. The Oregon spotted frog is listed as threatened under the ESA. They inhabit marshy edges of ponds and streams (Nordstrom and Milner 1997a). The only known Oregon spotted frog populations are in Thurston and Klickitat counties (Nordstrom and Milner 1997a; USFWS 2010). Western toads, a State Candidate Species, are found in more terrestrial habitats but occur near water bodies (Hallock and McAllister 2005). The presence of both of these species is unlikely, due to the small size of habitat, surrounding urbanization, and the rare status of these species in western Washington, as well as unreliable water levels and the presence of introduced predators, such as bullfrogs and sunfish. • Western pond turtle: Western pond turtles, a State Candidate Species, are found in streams, rivers, and ponds below 300 meters (985 feet) elevation in Washington State. They prefer open pond habitat with floating logs for basking (Hays et al. 1999). Appropriate habitat exists in the BRRFW; however, western pond turtles are unlikely to occur in the area, due to surrounding urbanization and the rare status of this species (Nordstrom and Milner 1997b). March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 15 • Yellow-billed cuckoo: Yellow-billed cuckoos are a State Candidate species, and are listed as threatened by the USFWS. Yellow-billed cuckoos nest almost exclusively in low elevation riparian habitat patches greater than 50 acres in size (58 FR 61633), which occurs in the BRRFW. However, the species is rare in Washington State—the last breeding records are from the 1930s; and only four of 17 sightings between 1956 and 2012 occurred west of the Cascades (58 FR 61634). • Vaux’s swift: Snags in the study area provide potential nesting habitat for Vaux’s swift, a State Candidate species that occurs in upland and wetland forest; however, Vaux’s swift are more closely associated with old-growth forested habitat, which is not present in the study area (Lewis et al. 2004). The City notes that 50 bird species have been documented in the BRRFW (Renton 2014b). The BRRFW contains numerous snags that could provide foraging habitat for pileated woodpeckers (Dryocopus pileatus). No pileated woodpeckers were observed during site visits for this project, but they were observed during wetland delineations for the nearby Lake to Sound Trail project (Parametrix 2013). The ponded area upstream of the BRPS is a popular wintering location for dabbling and diving ducks. Mallards (Anas platyrhynchos), gadwalls (A. strepera), American widgeon (A. americana), green-winged teal (A. carolinensis), northern shovelers (A. clypeata), wood ducks (Aix sponsa), ring-necked ducks (Aythya collaris) and buffleheads (Bucephala albeola) were all observed during surveys conducted by WDFW in January 2008 (Chris Anderson, WDFW, personal communication to John Koon, King County, on March 10, 2008). Results of Field Studies Habitat conditions were confirmed during field visits conducted in the spring and summer of 2014. Wetlands, streams, and upland habitats all occur within the study area (Figure 2). Wetlands Four wetlands consisting of palustrine emergent, scrub-shrub, and forested classes were delineated in the project area. Several other wetlands extend off-site in the BRRFW. These wetlands were not delineated for this project (Table 2; Figure 2). Wetlands and streams are described in detail in the Draft Wetland and Stream Delineation Report (Herrera 2014a) and only briefly summarized briefly here. Emergent wetlands are dominated by reed canarygrass, soft rush (Juncus effusus), slough sedge (Carex obnupta), and yellow flag iris. Forested and scrub shrub wetlands are dominated by Pacific willow (Salix lucida), Sitka willow (S. sitchensis), red alder (Alnus rubra), and Himalayan blackberry. March 2015 16 Habitat Data Report—Black River Pump Station Sediment Removal Project Table 2. Delineated Wetlands and Streams in the Study Area. Wetland Size (ft2/acre) Cowardin Classificationa Hydrogeomorphic Classificationb Ecology Rating Categoryc City of Renton Buffer Width (ft)d A 56,703/1.3 PEM, PSS, PFO Riverine II 225 B 1,220/0.03 PEM, PSS Depressional III 75 C 1,945/0.04 PEM, PSS, PFO Slope IV 50 D 40,300/0.93 PEM, PSS Depressional III 125 Black River NA NA NA NA 100 BRRFW wetlandse Not delineated for this project PFO, PSS, PEM Riverine and depressional I 225 a US Fish and Wildlife Service classification is based on Cowardin et al. (1979): palustrine forested (PFO), palustrine scrub-shrub (PSS), and palustrine emergent (PEM). b Hydrogeomorphic classification is based on Brinson (1993). c Wetland category is based on the Ecology wetland rating system (Hruby 2004), which is required for wetlands in Renton within shoreline jurisdiction (RMC4-3-090-D). d Wetland buffer widths are based on the Ecology wetland rating, per Renton Municipal Code 4-3-090-D. e Wetlands outside possible staging area locations were not delineated or rated for this project. Information on size, classification, and ratings was estimated based on existing documentation. Streams The Black River is the only stream present in the study area. The BRPS impounds water behind the pump station, creating a large, slow-moving pool. Large woody debris is limited, and no undercut banks or off-channel habitat were observed during site visits. Substrates are composed of several feet of fine-grained sand and silt. Aquatic vegetation consists of pondweed (Potamogeton spp.), with cattails (Typhus latifolia) and yellow flag iris at the water’s edge. A few algal mats were observed floating on the water surface during a site visit in July 2014 (Appendix A, Photo 1). The Black River is deeply incised downstream of the pump station, confined by retaining walls or steep banks lined with riprap. Upland Forest/Buffer Riparian vegetation upstream of the BRPS consists primarily of black cottonwood (Populus balsamifera), big-leaf maple (Acer macrophyllum), red alder, willows, red osier dogwood (Cornus sericea), cattails, Himalayan blackberry, reed canarygrass, and yellow flag iris (Appendix A, Photo 1). Downstream of the pump station the river is bordered by a narrow strip of riparian vegetation consisting primarily of Himalayan blackberry, with some small (2 to 4 inches dbh) willows and big-leaf maple (Appendix A, Photo 2). Upland forest is dominated by large, mature black cottonwood and red alder trees, with an understory of salmonberry (Rubus spectabilis), Indian plum (Oemleria cerasiformis), sword fern (Polystichum munitum), beaked hazelnut (Corylus cornuta), red osier dogwood, and Himalayan blackberry. Himalayan blackberry is prolific near wetland and stream margins, and has established some thick patches within upland forested areas. Upland forest within the project footprint is contiguous with the larger Black River Riparian Forest, which contains a diverse assemblage of upland and wetland plant species. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 17 Wetland buffer condition varies depending on the wetland. Buffers surrounding Wetland A consist of mixed deciduous and coniferous forest. Wetland B buffer has been disturbed by maintenance of the BRPS grounds and is mainly lawn dominated by Kentucky bluegrass (Poa pratensis), with some rose (Rosa spp.) and red elderberry (Sambucus racemosa). Wetland C buffer is disturbed forested and scrub-shrub upland containing willows, alder, rose, and extends onto the lawn. Buffers surrounding Wetland D are disturbed due to the presence of a bike path to the north and the BRPS and access road to the south. The eastern portion of the buffer is relatively intact, consisting of mixed deciduous and coniferous forest (Appendix A, Photos 3 and 4). Wetland buffers within the BRRFW extend into the upland forest as described above. Habitat Connectivity and Fragmentation Outside the BRRFW, land in the project vicinity is mostly developed urban land. The few remaining areas of vegetation represent patches within a highly fragmented landscape. Railroad corridors and major roads border the study area on most sides (Figure 1). A narrow vegetated corridor along Springbrook Creek provides some riparian habitat connectivity to other wetland systems to the south within the Green River valley. The Black River follows a narrow vegetated corridor that connects to the Green River corridor, providing connectivity with upstream and downstream riparian habitats; however, this corridor is interrupted by roadways, railroads, bridges, and commercial and industrial development. The King County online mapping system does not indicate any wildlife networks in the project area (King County 2014). The pump station has upstream and downstream fish migration systems. A fishway allows upstream fish passage between September and February and an air lift pump aids downstream migrants in passing the structure between April and June (Kerwin and Nelson 2000). Neither migration system is operational between June 1 and September 1 when the BRPS acts as a complete migration barrier between the Green River and Springbrook Creek. Critical Species Associated with On-Site Habitat Types Osprey and great blue heron were observed during site visits, as were several species of waterfowl. Surveys for great blue heron nests were conducted during the nesting season on June 4, 2014. Four nests were observed on the south side of the Black River near the rookery location, approximately 1,200 feet upstream of the BRPS, but no evidence of nesting or other heron activity was apparent at the nest sites. Several herons were observed foraging and roosting at the same location during site visits in June 2014 and January 2015. Numerous waterfowl were also present, including Canada geese (Branta canadensis), mallards, wood ducks, northern shovelers, buffleheads, widgeons, and ring-necked ducks. Comprehensive plant lists were compiled during wetland delineations for this project, and no Pacific peas were observed. This species is typically found in dry, open to wooded areas and forest edges near or within historical prairies (WDNR 2014b). This habitat does not occur in the study area. March 2015 18 Habitat Data Report—Black River Pump Station Sediment Removal Project Habitat Functions and Values Delineated wetlands in the study area generally provide low to moderate functions for water quality, hydrology, and habitat, with the exception of Wetland A, which has high water quality and habitat potential. Wetland A is well vegetated and has a high interspersion of habitat types, as well as depressional areas that can capture sediment during high water events. Wetlands further east in the BRRFW are higher value and provide a higher level of water quality, hydrology, and habitat functions. The Black River in the study area provides low-quality pool habitat for fish. There is sparse distribution of large wood, no undercut banks, and water quality is poor. Summer water temperatures are especially high and have been measured at over 20 degrees C. Riparian vegetation is well developed, but dominated in many areas by Himalayan blackberry upstream of the pump station, except immediately adjacent to the BRPS where the river is confined by steep riprapped slopes and retaining walls. Upland areas within the study area provide variable levels of functions, depending on the level of habitat alteration. Habitat functions are low in disturbed areas along the forest margin adjacent to the BRPS, railroad tracks, and Monster Road. Staging, sediment stockpiling, and water treatment will occur in a previously disturbed area between the pump station and Monster Road. Plant species diversity is lower here than other areas of the riparian forest. Invasive plant species such as reed canarygrass and Himalayan blackberry have established large patches in some areas and habitat structure is less complex. Habitat functions are moderate to high in more intact portions of the BRRFW, due to high plant species diversity, the presence of mature deciduous trees and snags, and complex vegetation structure consisting of a multilevel understory and overstory. Intact, naturally vegetated portions of the study area represent habitat value to the City because they contribute to the following City goals (RMC 4-3-050): • Maintain and promote diversity of species and habitat within the city • Coordinate habitat protection with the City’s open space system, whenever possible, to maintain and provide habitat connections • Help maintain air and water quality, and control erosion • Serve as areas for recreation, education, scientific study, and aesthetic appreciation In order to maintain these values on the project site, the project seeks to retain as much native vegetation as feasible and to compensate for any impacts that may occur from project activities by replanting cleared areas with native vegetation. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 19 R EGULATORY IMPLICATIONS Impacts on aquatic resources (e.g., wetlands, streams) are regulated under the federal Clean Water Act, Washington State Growth Management Act, Washington State Hydraulic Code, and the RMC Critical Areas and Shoreline Master Program Regulations. City regulations also establish development standards for buffers (including required widths) associated with wetlands and streams, and the City regulates habitat areas associated with critical fish and wildlife species. According to RMC 4-3-050 K, the Black River and the BRRFW are considered critical habitats based on presence of federal and State listed species and the BRRFW’s classification as a Category I wetland and Biodiversity Area. All project activities that may affect critical habitats must evaluate alternative methods of developing the property using the following criteria in this order: (1) avoid any disturbance to the habitat, (2) minimize any impacts on the habitat, and (3) compensate for any habitat impacts. If feasible, mitigation shall be provided on-site and in-kind. A habitat/wildlife assessment is required for activities located with or abutting a critical habitat, that are adjacent to a critical habitat, or have the potential to significantly impact a critical habitat. Based on the habitat assessment, the City Department of Community & Economic Development may designate the on-site critical habitat areas and their buffers as Native Growth Protection Areas, which may require establishment of a conservation easement or a similar permanent protective mechanism (RMC 4-3-050 K.2). March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 21 AVOIDANCE AND MINIMIZATION M EASURES Several measures have been incorporated into the project design and construction methods to avoid and minimize impacts on sensitive species and habitats: • The project has been designed to avoid wetland and buffer impacts to the greatest extent possible. After discussions with regulatory agencies, the City, and Herons Forever, the staging and water treatment area was relocated from the north side of the river to the south side, thereby eliminating impacts on Wetland D and reducing potential for disturbing the heron rookery. • Impact pile driving has been eliminated from consideration to minimize noise disturbance. • In-water work will occur during the approved in-water work window (July 1 to August 31). • Silt curtains, cofferdams, and other BMPs will be implemented to minimize turbidity. • Bypassing and dewatering the excavation area will minimize turbidity. • Silt curtains will be deployed when the pump station pumps are turned off, allowing sediments to settle before water is pumped downstream. • Sediment dewatering water will be treated to Ecology Surface Water Quality Criteria for turbidity and toxics before discharge into the Black River. • Sediment will be disposed of off-site at a facility permitted to accept the waste. • All cleared areas will be revegetated with native plant species following construction. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 23 P ROJECT IMPACTS AND MITIGATION Wetland Buffers and Vegetation Clearing Despite implementation of minimization measures and BMPs, the project will have unavoidable temporary impacts on stream and wetland buffers. The project will mitigate for buffer impacts by replanting cleared areas with appropriate native vegetation. Noise Noise from construction may affect wildlife species. Project construction will occur between late May and September, which overlaps with the bald eagle and great blue heron breeding season, among other species. Because work needs to occur during the in-water work window, the project cannot be timed to avoid nesting. Baseline noise measurements were conducted in August 2014 to evaluate potential impacts on the heron colony during construction (Hart Crowser 2014). Measurements were conducted with and without pump operations at both the pump station structure and near the great blue heron rookery: • The baseline noise level measured at the BRPS structure without pumps operating was approximately 56 decibels (dBA), increasing to nearly 67 dBA when pump 1 was operating, and to over 79 dBA when pumps 1 and 2 were operating simultaneously. • Pump noise did not extend to the rookery: baseline noise level measured near the great blue heron colony without pumps operating was approximately 49 dBA and remained the same whether pumps were on or off. Noise levels reached as much as 62 dBA during periods of intermittent noise, such as when helicopters or trains passed by. WDFW recommends a 200-meter (656-foot) buffer around heron nesting colonies for activities that would generate sound exceeding 92 dBA (Azerrad 2012). Noise generated by construction equipment will not reach that threshold; maximum construction noise levels are estimated to be roughly 90 dBA. Project noise will decrease by about 7.5 dB per doubling distance from the source (WSDOT 2014). Construction noise will therefore decrease to about 52.5 dBA at the edge of the heron colony, only slightly above baseline noise and well below levels that would disturb herons. During design, impact pile driving was eliminated from consideration as a possible construction method to minimize potential noise impacts. The staging area was moved to reduce visual impacts on the heron colony. No additional mitigation is proposed. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 25 R EFERENCES Azerrad, J.M. 2012. Management recommendations for Washington’s priority species: Great Blue Heron. Washington Department of Fish and Wildlife, Olympia, Washington. Brinson, M.M. 1993. A Hydrogeomorphic Classification for Wetlands. Technical Report WRPDE- US Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. August 1993. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. Publication FWS/OBS-79/31. US Department of the Interior, Fish and Wildlife Service, Office of Biological Services. Ecology. 2012. Washington State Department of Ecology Water Quality Assessment and 303(d) list. Available online at https://fortress.wa.gov/ecy/wqamapviewer/default.aspx?res=1920x1080. Accessed July 8, 2014. Hallock, L.A. and K.R. McAllister. 2005. Western toad. Washington Herp Atlas. http://www1.dnr.wa.gov/nhp/refdesk/herp//. Hart Crowser. 2014. Sediment Characterization Sampling and Noise Monitoring: Black River Pump Station, Renton, Washington. Memorandum to Tom Bean, KCWLRD on December 1, 2014. Hays, D.W., K.R. McAllister, S.A. Richardson, and D.W. Stinson. 1999. Washington State Recovery Plan for the Western Pond Turtle. Washington Department of Fish and Wildlife, Olympia, Washington. Herrera. 2014a. Draft Wetland and Stream Delineation Report, Black River Pump Station Sediment Removal Project. Herrera Environmental Consultants, Inc., Seattle, Washington. May 16, 2014. Herrera. 2014b. Draft Biological Evaluation, Black River Pump Station Sediment Removal Project. Herrera Environmental Consultants, Inc., Seattle, Washington. August 18, 2014. Hruby, T. 2004. Washington State Wetland Rating System for Western Washington — Revised. Ecology Publication 04-06-025. Washington State Department of Ecology. August 2004. Kerwin, J. and T.S. Nelson. (Eds). December 2000. Habitat limiting factors and reconnaissance assessment report, Green/Duwamish and Central Puget Sound watersheds (WRIA 9 and Vashon Island). Washington Conservation Commission and the King County Department of Natural Resources. King County. 2008. King County Environmental Lab Matrix Report #12983, Project 421195. March 2015 26 Habitat Data Report—Black River Pump Station Sediment Removal Project King County 2014. King County iMAP Map Set: Sensitive Areas. Accessed online at http://www.kingcounty.gov/operations/GIS/Maps/iMAP/MapSets/SensitiveAreas.aspx September 15, 2014. Lewis, J.C., M. Whalen, and R.L. Milner. Vaux’s Swift in Management Recommendations for Washington’s Priority Species, Volume IV: Birds edited by E.M. Larsen, J.M. Azerrad, and N. Nordstrom. Washington Department of Fish and Wildlife, Olympia, Washington. Pages 25-1 through 25-5. Nordstrom, N. and R. Milner. 1997a. Oregon Spotted Frog (Rana pretiosa) in Management Recommendations for Washington’s Priority Species, Volume III: Amphibians and Reptiles edited by E.M Larsen. Washington Department of Fish and Wildlife, Olympia, Washington. Pages 7-1 through 7-10. Nordstrom, N. and R. Milner. 1997b. Western Pond Turtle (Clemmys marmorata) in Management Recommendations for Washington’s Priority Species, Volume III: Amphibians and Reptiles edited by E.M Larsen. Washington Department of Fish and Wildlife, Olympia, Washington. Pages 7-1 through 7-10. Parametrix. 2011. Wetland Discipline Report, Lake to Sound Trail Segment A. Prepared for King County Parks Division. Parametrix, Inc., Bellevue, Washington. October 2011. Parametrix. 2013. Vegetation and Wildlife Discipline Report, Lake to Sound Trail. Prepared for King County Parks Division. Parametrix, Inc., Bellevue, Washington. June 2013. Renton. 2004. City of Renton Comprehensive Plan. Available online at http://rentonwa.gov/business/default.aspx?id=2684. Accessed on September 3, 2014. Renton. 2014a. City of Renton online mapper. Accessed August 20, 2014 at http://www.rentonweb.org:8080/SilverlightPublic/Viewer.html?Viewer=COR-Maps. Renton. 2014b. City of Renton website. Accessed August 22, 2014 at http://rentonwa.gov/living/default.aspx?id=16494. Stober, Q.J. and K.B. Pierson. 1984. A review of the water quality and marine resources of Elliott Bay, Washington. Available online at https://digital.lib.washington.edu/researchworks/handle/1773/4027. Towry, R.K. 1987. Wildlife habitat requirements. Pages 73–210 in R. L. Hoover and D. L. Wills, editors. Managing Forested Lands for Wildlife. Colorado Division of Wildlife, Denver, Colorado, USA. USFWS. 2010. U.S. Fish and Wildlife Service Species Assessment and Listing Priority Assignment Form: Oregon spotted frog. Available online at http://ecos.fws.gov/docs/candforms_pdf/r1/D02A_V01.pdf. USFWS. 2014. U.S. Fish and Wildlife National Wetlands Inventory mapper. Accessed online at http://www.fws.gov/wetlands/Data/Mapper.html. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project 27 WDFW. 2014. Washington Department of Fish and Wildlife Priority Habitat and Species data. Obtained August 4, 2014. WDNR. 2014a. Washington Department of Natural Resources Rare Plants and High Quality Ecosystems data. Shapefiles downloaded on 8/20/14 from http://fortress.wa.gov/dnr/app1/dataweb/dmmatrix.html. WDNR. 2014b. Washington Department of Natural Resources Natural Heritage Information System List of Known Occurrences of Rare Plants in Washington: Pacific pea. Available online at http://www1.dnr.wa.gov/nhp/refdesk/fguide/pdf/laveo2.pdf. Woodruff, K. and H. Ferguson. 2005. Townsend’s big-eared bat. Pages 24–36 in E. Larsen, J.M. Azerrad, N. Nordstrom, editors. Management Recommendations for Washington’s Priority Species, Volume V: Mammals. Washington Department of Fish and Wildlife, Olympia, Washington. WSDOT 2014. Washington State Department of Transportation Biological Assessment Guidance: Noise Impact Assessment. Available online at http://www.wsdot.wa.gov/NR/rdonlyres/448B609A-A84E-4670-811B- 9BC68AAD3000/0/BA_ManualChapter7.pdf. APPENDIX A Project Area Photos March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project A-1 Photo 1. Black River and riparian vegetation upstream of the BRPS. March 2015 A-2 Habitat Data Report—Black River Pump Station Sediment Removal Project Photo 2. Black River and riparian condition downstream of the BRPS. March 2015 Habitat Data Report—Black River Pump Station Sediment Removal Project A-3 Photo 3. Wetland D and buffer facing west. March 2015 A-4 Habitat Data Report—Black River Pump Station Sediment Removal Project Photo 4. Wetland D and buffer facing northeast towards the BRRFW.