BIOLOGICAL EVALUATION

Transcription

1 BIOLOGICAL EVALUATION \ For Sensitive Fish and Wildlife Species at the Proposed New Dock at Lake Sammamish State Park, Issaquah, WA: NWS Prepared for: U.S. Army Corps of Engineers 4735 East Marginal Way South Seattle, WA Prepared on behalf of: Washington State Parks and Recreation Commission c/o Robert Droll th Avenue SE Lacey, WA Prepared by: February 2018 The Watershed Company Reference Number: The Watershed Company Contact Person: Jenni Creveling/Sarah Sandstrom Cite this document as: The Watershed Company Biological Evaluation for Sensitive Fish and Wildlife Species at the Proposed New Dock at Lake Sammamish State Park, Issaquah, WA

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3 TABLE OF CONTENTS Section Page No. 1 Project Overview Consultation History Project Location General Description Construction Sequence Impact Minimization Measures Action Area Listed Species Description of Project Area and Baseline Conditions Species Information and Site Use Chinook Salmon Bull Trout Steelhead Species Impacts Direct Effects on Salmonids Indirect Effects on Salmonids Critical Habitat Chinook Salmon Bull Trout Steelhead Cumulative Impacts Determination of Effect Chinook Salmon Bull Trout Steelhead Critical Habitat Effect Determinations Summary Essential Fish Habitat Project Description EFH Conservation Measures Species Description and Site Use Effects of the Project References Appendix A: Project Plans

4 TABLE OF CONTENTS (cont d) Page No. List of Tables Table 1. Proposed overwater and shoreline buffer impacts associated with the fixed-pile pier, floating dock, gangway, wave attenuator, and concrete path Table 2. Proposed measures to offset impacts... 4 Table 3. Proposed work window Table 4. Listed species that may use the project area (NMFS/USFWS as of September 13, 2016). 9 Table 5. Determination of Effect List of Figures Figure 1. Vicinity map (Bing.com)... 2 Figure 2. General depiction of project action area, with area of potential airborne noise (0.85 mile radius) in yellow. The aquatic action area extends approximately 72 feet from project operations (red) Figure 3. View of shoreline area looking south Figure 4. View of shoreline area north of the proposed dock, looking north Figure 5. View of lake where dock, gangway, and paths are proposed, looking south (prior to beach restoration work)

5 B IOLOGICAL E VALUATION SECTION 7, ENDANGERED SPECIES ACT Applicant: Washington State Parks and Recreation Commission, c/o Robert Droll Corps Reference #: NWS PROJECT OVERVIEW 1.1 Consultation History The current project is proposed at Sunset Beach in Lake Sammamish State Park. Previous park improvements have occurred in the Sunset Beach area. Earlier improvements included removal of milfoil in the beach area, sediment removal and replacement fill to remove sink holes in the swim area, installation of a concrete ramp into the water that is compliant with Americans with Disabilities Act (ADA) standards, replacement of the upland beach substrate and installation of a subsurface drainage system (NWS ). Mitigation for these improvements included lake-fringe and depressional wetland creation and enhancement in the vicinity of the beach area. A dock, and the other improvements proposed under the current plan were not proposed at the time of the previous beach improvements. 1.2 Project Location The proposed project is located at Sunset Beach in Lake Sammamish State Park, on the southern shoreline of Lake Sammamish in Water Resource Inventory Area 8 (WRIA 8). The park is located at 5000 NW Sammamish Road, King County, WA (in Section 20, Township 24 North, Range 6 East; N Latitude, W Longitude; Figure 1). Tax parcel numbers: and Sunset Beach is bordered to the north and west by Lake Sammamish and to the south and east by the 512-acre Lake Sammamish State Park. The Watershed Company TWC Ref #: February 2018 Page 1

6 Proposed Project Site Figure 1. Vicinity map (Bing.com) 1.3 General Description The Washington State Parks and Recreation Commission (State Parks) proposes to install a new floating dock, a wave attenuator, and associated gangways and pathways, in the Sunset Beach area of Lake Sammamish State Park. Opened in 1952, Lake Sammamish State Park has been one of the more popular destinations for swimmers and boaters in Western Washington for the past 64 years. Washington State Parks Commission is currently in the process of implementing improvements to update heavily used and deteriorating facilities, improve safety, and better accommodate the recreational needs an expanding population base. A boat launch at the north end of the park provides public boater access to the waters of Lake Sammamish. Data from recent years shows summer weekend use often exceeds 900 launches per day. There are also boaters coming onto the lake from other launches, in addition to those moored at private facilities, who sometimes visit the Sunset Beach Day-Use Area. Many of these boaters anchor or haul ashore along the southern end of Sunset Beach as families and friends picnic at the park. The location where boats haul ashore is immediately waterward from the wetland mitigation area completed in For years, boats coming and going for waterskiing, tubing and cruising in the same areas as swimmers has presented dangerous boater/swimmer conflicts and has resulted in shoreline degradation. In 2015, construction of a new bathhouse was completed at Sunset Beach, complete with changing rooms and expanded restroom facilities. With the new dock in place, restroom use will be a more accessible option for boaters. In addition to typical beach use, the Association of Volleyball Professionals Championships have been held at Sunset Beach at Lake Sammamish State Park for the past two years, and will continue for the foreseeable future. This event draws national exposure and spectators in the thousands. The site has also become popular for other TWC Ref #: The Watershed Company Page 2 February 2018

7 high attendance events to which some attendees prefer to arrive by boat. These events will attract greater than normal user numbers to the dock. The currently proposed park improvements are designed to enhance recreational opportunities, safety, and access. Once the dock is installed, along with a wave attenuator, the swimming area will be more protected, eliminating the dangers of boater/swimmer conflicts within the swim area. A defined swim area will improve public safety by making it easier to visually monitor swimmers and to detect and rescue distressed swimmers. Boaters will be able to access the park from the dock rather than pulling their boats into the shoreline, which will create safer conditions for swimmers and less impact to the shoreline from vessel grounding. The project will also improve shoreline environmental conditions through enhancement of riparian vegetation. The dock will provide for mooring, boat alighting and boarding, swimming activities, and fishing on the northern dock Project Design Under the current proposal, a branching dock is proposed (see Appendix A for project plans). The dock is 245 feet long with a 200-foot-long arm paralleling the shoreline and another 140-foot-long arm angling off to the north. An elevated, fixed-pile pier extends approximately 60 feet waterward from the OHWM. A 49-foot-long aluminum grated gangway connects the fixed-pile pier to the floating dock. Four 10-inch diameter piles, inch-diameter piles, seven 16-inch-diameter piles, and three 24-inch-diameter steel piles will be driven using a vibratory driver. No piles will be located any closer than 50 feet from the shoreline. Floating dock segments are eight to ten feet wide and surfaces are fully grated. The widths of floating dock segments are the minimum necessary to accommodate the expected amount and variety of activity on the dock, as well as anticipated wave forces. Docking and boarding boating activity, transport of supplies from the dock to the dayuse area, swimming and sunbathing, and fishing activity are all expected to occur simultaneously on the dock. Narrower docks have been found to be unable to handle multiple uses in a public space safely and would not adequately accommodate all of the expected activity. In addition, with the anticipated traffic, weight/load concentrations will be in constant movement, shifting from side to side over the length of the dock. The proposed dock width will be stable to resist lateral tipping, reducing the potential for users to lose balance and fall. Float and framing structure will be present below the decking. The area of float material has been minimized to maximize light penetration through the grated dock. The use of floats also allows the number of piles to be reduced compared to a fixed-pile pier. The Watershed Company TWC Ref #: February 2018 Page 3

8 A wave attenuator is proposed extending south from the proposed dock. This structure will be fabricated from high-density polyethylene (HDPE)) material. Each wave attenuator segment will be secured to one 16-inch pile. A swim area float line will extend between the farthest south wave attenuator and the beach. Landward of the OHWM, 403 square feet of new concrete pathway will be installed connecting the existing path and recreation area to the beach and dock. A small portion (207 square feet) of the fixed-pile pier will also be located landward of the OHWM. Overwater and buffer impacts will be mitigated through a combination of overwater structure removal and native vegetation planting. A 400 square foot derelict barge located along the shoreline north of the proposed dock will be removed. In addition, 6,330 square feet of native vegetation will be planted near the dock, adjacent to Wetland B. In total, all overwater and buffer impacts will be mitigated at a ratio of 1:1 (Tables 1 and 2). Table 1. Proposed overwater and shoreline buffer impacts associated with the fixed-pile pier, floating dock, gangway, wave attenuator, and concrete path. Impacts Area (Square feet) Overwater (Waterward of OHWM) Fixed-Pile Pier and Floating Dock 5,363 Gangway 187 Wave Attenuator 735 Shoreline Buffer (Landward of OHWM) Fixed-Pile Pier 207 Concrete Path 403 Total Impact Area 6,929 Table 2. Proposed measures to offset impacts Mitigation Area (Square feet) Barge Removal 400 Native Planting adjacent to Wetland B 6,529 Total Mitigation Area 6, Construction Sequence Construction activities would occur in the following sequence (provided by Robert Droll Landscape Architects and modified by The Watershed Company). 1) Initiate off-site fabrication of dock floats, gangway and wave attenuator 2) Identify and mark sensitive areas 3) Install temporary erosion and sediment control (TESC) measures 4) Earthwork and construction of pavement, abutments and crushed rock trail TWC Ref #: The Watershed Company Page 4 February 2018

9 5) Install piles using vibratory pile driver 6) Install mitigation plantings per plan specifications 7) Install dock floats, gangways and wave attenuators 8) Clean-up, removal of TESC measures and other demobilization 1.5 Impact Minimization Measures The following measures will ensure that disturbance to sensitive fish and wildlife species utilizing the action area will be minimized. Timing Restriction Construction involving in-water work is expected to take four weeks to complete. Per the combined policies of the National Marine Fisheries Service (NMFS) and U.S. Fish and Wildlife Service (USFWS) to protect bull trout (Salvelinus confluentus), steelhead (Oncorhynchus mykiss), and Chinook salmon (O. tshawytscha) in the portion of Lake Sammamish within the Action Area, no in-water work is generally allowed to occur from January 1st through July 15th nor from August 1st through November 15th. The proposed project is also located within a WDFW-indexed sockeye salmon (O. nerka) spawning area, so additional timing restrictions from WDFW are applicable. WDFW typically requires in-water activities in Lake Sammamish to be conducted between July 16th and September 30th to protect sockeye. Combining these timing restrictions would leave only a two-week in-water work window between July 16th and July 31st. This would not be enough time to complete the project. We propose limiting in-water work to the WDFW approved work window of July 16th to September 30th (Table 3). This timing restriction will limit in-water work to the time when salmonids are least likely to be present in the work area (see Section 4), while still accommodating a practical timeframe for construction. This work window was applied to the recent beach restoration work at Lake Sammamish State Park. The proposed timing restrictions are depicted graphically in Table 3. The applicant would comply with any amendments made to the timing restrictions following U.S. Army Corps of Engineers (Corps), NMFS, USFWS, and WDFW review. The Watershed Company TWC Ref #: February 2018 Page 5

10 Table 3. Proposed work window. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Federal work window State work window Proposed work window No in-water work No in-water work No in-water work No in-water work No in-water work No in-water work Construction activities that can be performed landward of the OHWM may take place at any time. Construction activities that can be performed above the OHWM include construction of the concrete pathway and the upland planting. Minimization of Construction Impacts In water work- The pier pilings will be installed using a vibratory driver to limit noise impacts during construction. All in-water work will be staged from a barge. The barge will not be allowed to ground. In order to prevent debris from entering the lake during the project, a containment boom will surround the crane barge and work area during dock construction. All wood preservatives will be state-approved and will be applied and fully cured prior to installation over the water. Upland work- The proposed project involves construction of an upland concrete pathway. This activity has the potential to cause elevated turbidity levels within the action area. The following minimization measures will be implemented to limit project effects from turbidity. a. The Contractor will develop and implement a Temporary Erosion and Sediment Control (TESC) plan. b. A silt fence will be installed and maintained around the project area for the duration of work. c. A construction staging area will be established in the existing parking area, well away from the water s edge. d. The contractor will stockpile excavated material at an upland site pending offsite disposal. Minimization of Impacts to Shallow Water Habitat The pier was designed to minimize impacts to shallow water habitat. Specifically, no piles will be located closer than 50 feet to the shoreline, and the gangway is limited to five feet in width in the nearshore feet. Additionally, in order to minimize effects TWC Ref #: The Watershed Company Page 6 February 2018

11 of shading, the entire deck and gangway will be fully grated. While float and framing structure will be present below the decking which will limit light transmission to the inner four feet of the dock, the area of float material has been minimized to maximize light penetration to the greatest extent possible. Additionally, the size and number of piles proposed are the minimum necessary to provide a stable platform for the anticipated intensity of public use and anticipated wave conditions caused by the combination of boat wakes and wind-driven waves. 1.6 Action Area Action area is defined as all areas to be affected directly or indirectly by the proposed action and not merely the immediate area involved in the action. The aquatic action area is based on the distance for aquatic noise to attenuate to background conditions. Disturbance effects of this project on Chinook salmon, bull trout and steelhead would be realized within 225 feet of project operations based on a practical spreading loss equation from vibratory pile driving of 24-inch diameter steel piles, assuming an RMS value of db 1. Airborne noise from construction is expected to attenuate to background levels within a 0.85 mile radius of the pier. This distance was calculated with the practical spreading loss equation, using inputs based on noise levels measured for a vibratory pile driver at 94 db at 50 feet from the source and ambient noise of 50 db measured 50 feet from the source (WSDOT 2017). No other areas would be affected directly or indirectly. The project action area is displayed in Figure 3. 1 This value is the average between typical sound measurements for a 12-inch and 36-inch pile. California (Illinworth and Rodkin 2007) The Watershed Company TWC Ref #: February 2018 Page 7

12 Figure 2. General depiction of project action area, with area of potential airborne noise (0.85 mile radius) in yellow. The aquatic action area extends approximately 72 feet from project operations (red). 2 LISTED SPECIES The action area is located along the shoreline of Lake Sammamish, which lies within the geographic range of three federally listed species of salmonids: 1) Chinook salmon of the Puget Sound Evolutionary Significant Unit (ESU) (Reaffirmed as Threatened, Federal Register, 28 June 2005), 2) bull trout of the Coastal-Puget Sound Distinct Population Segment (DPS) (Threatened, Federal Register, 1 November 1999), and 3) steelhead of the Puget Sound DPS (Threatened, Federal Register, 11 May 2007). Coho salmon of the Puget Sound-Strait of Georgia ESU are also present in the watershed and are currently considered a Species of Concern (Federal Register, 15 April 2004), indicating that they are under less active consideration for formal listing. An ESU of Pacific salmon is considered to be a DPS and thus a species under the Endangered Species Act. Although critical habitat has been designated for Puget Sound Chinook salmon and Coastal-Puget Sound bull trout, Lake Sammamish was excluded and does not contain designated critical habitat for either of these fish species. Critical habitat was recently proposed for Puget Sound steelhead trout, but the proposed listing also TWC Ref #: The Watershed Company Page 8 February 2018

13 excludes Lake Sammamish (Federal Register, 14 January 2013). All of these species may be present in the action area during a portion of their life cycle. Lake Sammamish kokanee were recently considered for listing, but were not listed (Federal Register, 4 October 2011); therefore, they will not be addressed further in this document. Table 4. Listed species that may use the project area (NMFS/USFWS as of September 13, 2016). Species Federal Status ESU/DPS/Region Chinook salmon Oncorhynchus tshawytscha Bull trout Salvelinus confluentus Steelhead Oncorhynchus mykiss 1 Federal Register, 28 June Federal Register, 1 November Federal Register, 11 May Reaffirmed, June Puget Sound DPS No 4 Threatened, November Coastal-Puget Sound DPS No 5 Threatened, May Puget Sound DPS No 6 4 Federal Register, 2 September Federal Register, 26 September Federal Register, 14 January Critical Habitat in Action Area In addition to listed salmonids, the US Fish and Wildlife Service identifies the following listed species as occurring in King County: Oregon spotted frog, northern spotted owl, marbled murrelet, yellow-billed cuckoo, Canada lynx, gray wolf, grizzly bear, and golden paintbrush. The Oregon spotted frog requires perennial bodies of water adjacent to expansive meadow or wetland vegetation to complete its life cycle. In Washington, Oregon spotted frogs are known to occur only within six subbasins/watersheds: the Sumas River; Black Slough in the lower South Fork Nooksack River; the Samish River; Black River, a tributary to the Chehalis River, Outlet Creek, a tributary to the Middle Klickitat River; and Trout Lake Creek, a tributary of the White Salmon River (U.S. Federal Register, 29 August, 2014). A historical population of Oregon spotted frog occupied the lower Green River near Kent, and human development is generally assumed to be responsible for the loss of that population (U.S. Federal Register, 29 August, 2014). The habitat required for completion of the Oregon spotted frog s life cycle includes shallow water for egg and tadpole survival; perennially deep, moderately vegetated pools for adult and juvenile survival in the dry season and perennial water for protecting all age classes during cold wet weather. Typically, emergent wetlands along riverine systems support remaining Oregon spotted frog populations. Wetland habitats supporting Oregon spotted frogs are typically larger than nine acres (U.S. Federal Register, 29 August 2014). The WDFW Screening Model (2004) was used to determine the likelihood of site occupancy by the Oregon spotted frog within the Action Area based on existing The Watershed Company TWC Ref #: February 2018 Page 9

14 environmental conditions (Germaine and Cosentino 2004). The model screens for potential suitability of wetland sites using a two- tiered approach. The candidate wetland must pass all criteria in Tier 1, to be considered by the Tier 2 criteria which identifies seasonal on-site characteristics. Wetlands within the action area do not meet all criteria in Tier 1 to support the presence of Oregon spotted frog. The majority of the wetlands within the Action Area do not meet the NWI classification (palustrine emergent) criteria in Tier 1, nor do they meet the wetland size criteria or National Land Cover Definition (NLCD) landscape composition, which requires less than 9.8% development within a mile of the wetland s perimeter. Wetlands in the Action Area are also smaller than 8.9 acres and more than 10% of the area within a mile of the wetlands consist of residential and urban development. Therefore, no wetlands within the Action Area are considered potentially suitable for Oregon spotted frog presence. For this reason, the project will have no effect on Oregon spotted frog or its designated critical habitat and this species will not be further addressed in this document. There are no mature coniferous forests located within or in the vicinity of the action area that contain breeding or foraging habitat suitable for northern spotted owls or marbled murrelets. Northern spotted owls do not normally nest outside of mature, closed-canopy forests, which are not present in the action area, and trees of preferred perching and roosting size are not available on the site. Marbled murrelets inhabit mature, coniferous forests in dense coastal stands and forage in marine nearshore areas, neither of which are present in the action area. Yellow-billed cuckoos are extremely rare in Washington and are restricted to large willow and cottonwood forests along large rivers. While some willow and cottonwood are found along the Issaquah Creek shoreline within the Action Area, these are not the dominant species and the area consists of a narrow riparian corridor adjacent to an urban environment. As the size of the riparian zones are small compared to the yellow-billed cuckoo s preferred size, and given the rarity of yellow-billed cuckoo in Washington State and the sub-optimal habitat conditions in the project area, it is very unlikely that yellow-billed cuckoos would be present in the action area. Therefore, the project will have no effect on northern spotted owl, marbled murrelet, or yellow-billed cuckoo or their designated critical habitats and these species will not be further addressed in this document. Grey wolf, Canada lynx, and grizzly bear suitable habitat may occur in eastern King County, but not in the urban and suburban areas of western King County. Therefore, the project will have no effect on grey wolf, Canada lynx, or grizzly bear and these species will not be further addressed in this document. The action area does not contain suitable prairie conditions needed to support golden paintbrush, and there is no historical record of golden paintbrush occurring in the action area. Therefore, the project will have no effect on golden paintbrush, and this species will not be further addressed in this document. TWC Ref #: The Watershed Company Page 10 February 2018

15 3 DESCRIPTION OF PROJECT AREA AND BASELINE CONDITIONS The baseline conditions that Chinook salmon, bull trout, and steelhead presently face in the Lake Washington/Lake Sammamish watershed are described in the Salmon and Steelhead Habitat Limiting Factors Report for WRIA 8 (Kerwin 2001) and the Lake Washington/ Cedar/Sammamish Watershed (WRIA 8) Chinook Salmon Conservation Plan (WRIA ). This discussion describes the relevant site-specific baseline conditions within the action area, in particular focusing on those items that are different in condition than the watershed as a whole. The Watershed Company staff conducted a site visit on August 4, The following description of existing conditions is based upon observations from this site visit and materials supplied by the applicant. The elevation of Lake Sammamish at the USGS gauge near Redmond was feet (NAVD88) at the time of the 2016 site visit. Existing site conditions are characterized by the recently enhanced (previously permitted) sandy swim beach. Below the OHWM, native material was excavated and backfilled with imported granolithic aggregate on top of compact quarry spall and permeable ballast. Above the OHWM native beach sand was excavated and replaced with new beach sand. Boulders and large woody debris were also placed within the beach area. The swim beach is surrounded by wetland areas. Lake-fringe wetland is present southwest of the swim beach, and a wetland creation and shoreline enhancement mitigation project is southeast of the swim beach. Wetland enhancement and wetland creation mitigation was also recently installed further landward around a new bathhouse. A new play structure is also located in the project vicinity. The proposed work area is surrounded by active recreational uses, as well as some passive use areas. In addition to the swim beach, existing recreational use facilities include a concession stand, picnic tables, restrooms, and concrete pathways. The park sees significant use by swimmers and beach-goers during the summer months, and the lake gets heavy powerboat and jet-ski traffic. The park provides habitat for a variety of waterfowl as well as great blue herons, raptors, and other birds. The Watershed Company TWC Ref #: February 2018 Page 11

16 Figure 3. View of shoreline area looking south. Figure 4. View of shoreline area north of the proposed dock, looking north. TWC Ref #: The Watershed Company Page 12 February 2018

17 Figure 5. View of lake where dock, gangway, and paths are proposed, looking south (prior to beach restoration work). 4 SPECIES INFORMATION AND SITE USE General and site-specific information about each species is presented below. General and lake-specific life history information related to temperature, diet, and migration is also contained in the Federal Register listings cited in Table Chinook Salmon One demographically independent population of Chinook salmon is recognized in the Sammamish River watershed (NMFS 2006). A portion of this population spawns in tributaries of the Sammamish River (e.g., North Creek, Bear Creek, and Little Bear Creek), and another portion migrates through Lake Sammamish en-route to the Issaquah Creek Hatchery or spawning grounds in lower Issaquah Creek. Individual Chinook salmon have also been observed in Laughing Jacobs Creek (approximately one half mile east of the project area) and Lewis Creek (approximately 1.5 miles northwest of the project) (WRIA 8 electronic reference). Natural spawning predominantly takes place in Issaquah Creek and its East Fork. Adult Chinook salmon begin migrating into Issaquah Creek in September and finish spawning in November (Berge et al. 2006). Progeny of naturally spawning Chinook salmon from Issaquah Creek may enter the lake as fry in early January. Parr are released from the Issaquah Hatchery in May and early June, and they enter Lake Sammamish shortly thereafter. The majority of the juvenile Chinook salmon in the Lake Washington watershed migrate from the system The Watershed Company TWC Ref #: February 2018 Page 13

18 by mid-summer, and the remaining juveniles migrate out of the watershed by September. The early-entering fry are closely associated with the shoreline, while parr entering in May are less closely associated with shallow-water shoreline habitats (Tabor et al. 2004, 2006). Densities of juvenile Chinook salmon captured in the southern Lake Sammamish lakeshore and small creek deltas from March to June were among the highest of 13 sites sampled in Lake Washington and Lake Sammamish in 2002 (average densities ranging from 0.1 to 0.6 fish per square meter) (Tabor et al. 2004). Similarly, bimonthly snorkel surveys in the spring of 2014 have confirmed high densities of Chinook fry using the swim beach at Lake Sammamish State Park (H. Berge, personal communication with Sarah Sandstrom, March 6, 2014). Summer surface temperatures in Lake Sammamish exceed the thermal preferences of most salmonids, including Chinook salmon. Thermal stratification in Lake Sammamish usually begins in late May and extends until mid-november. Thermal stratification results in elevated epilimnetic (upper layer) temperatures, coinciding with decreasing dissolved oxygen levels throughout the hypolimnetic (lower layer) zone (Kerwin 2001). The reduced oxygen in the hypolimnion combined with relatively warm temperatures in the epilimnion serves to constrict the suitable habitat area available to salmonids during the summer. Thus, neither juveniles nor adults are expected in nearshore waters from June through September. In conclusion, juvenile Chinook salmon are likely to migrate through or rear in the action area from January through June, and adult Chinook salmon may be in the action area from late August to November. Therefore, adult Chinook may be near the action area during the later part of the proposed work window, but would not be expected in the nearshore area. 4.2 Bull Trout Native char (either bull trout or Dolly Varden) are rare in Lake Sammamish or its tributaries (U.S. Federal Register, 1 November 1999). No bull trout were observed during a one-year creel survey conducted on Lake Sammamish, and only a single bull trout was recorded during a two-year creel survey on Lake Washington (Pfeiffer and Bradbury 1992). Two bull trout, possibly anadromous fish that had strayed, were observed in the headwaters of Issaquah Creek in 1993 (WDFW 2002). Bull trout are known to exhibit pioneering behavior, spawning in areas other than their native stream. Bear Creek, a tributary to the Sammamish River downstream from Lake Sammamish, is listed as potential bull trout habitat by the USFWS (Kerwin 2001). However, there is no known resident subpopulation of bull trout in Lake Sammamish or its tributaries. TWC Ref #: The Watershed Company Page 14 February 2018

19 Due to their narrow thermal-tolerance range, it is likely that any adfluvial or anadromous bull trout in Lake Sammamish would be confined to the hypolimnion from mid- to late-may through mid-october, with some annual variation depending on the weather patterns. Given the anoxic conditions typically present throughout the hypolimnion in Lake Sammamish during this period, benthic foraging would be restricted (Kerwin 2001). Any spawners would begin upstream migrations from April through July, and immature fish would be likely to migrate upstream with the spawners to avoid the high temperatures in Lake Sammamish. In summary, bull trout presence in the action area is highly unlikely anytime during the year, and in particular, bull trout would not be expected to occur in the project vicinity from late spring to fall. 4.3 Steelhead Steelhead historically occurred throughout the Lake Washington basin, and likely spawned in Lake Sammamish tributaries, primarily Issaquah Creek. The steelhead spawning period throughout the basin extends from mid-december through early June. Two life forms of O. mykiss are commonly distinguished based on life history characteristics: anadromous (steelhead) and resident (rainbow trout). Both anadromous steelhead and resident rainbow trout are present in the Lake Washington watershed, including Lake Sammamish. Juveniles generally migrate seaward as smolts in March to early June after two years of stream residence, although duration of freshwater rearing can range from 1 to 7 years before juveniles grow large enough (>170 mm) to undergo smoltification. Because steelhead are typically larger and more mobile compared to juvenile Chinook salmon when they enter the lake, they are not dependent on shallow, nearshore habitats for predator refugia. Within the Lake Washington basin, steelhead are characterized as winter run, beginning river entry in December, and spawning from February through May (Kerwin 2001) Lake Washington winter steelhead are currently present in Lake Sammamish in low numbers and are identified by WDFW (2002) as a discrete stock within the Puget Sound steelhead DPS. They are characterized as a native stock with wild production, and their stock status was adjusted downward from depressed to critical in 2002 due to chronically low escapements and severe short-term declines in escapement in 2000 and As of 2004, these escapement numbers had not increased (WDFW 2002), and total escapement estimates for the Lake Washington basin between 2000 and 2004 ranged between 20 and 48 fish. As such, very few of these fish are likely to pass through Lake Sammamish to spawn in its tributaries. Summer surface temperatures in Lake Sammamish greatly exceed the thermal preferences of most salmonids, including steelhead. Thermal stratification in Lake Sammamish generally extends from late May to mid-november, elevating water temperatures in the epilimnion and decreasing dissolved oxygen levels in the The Watershed Company TWC Ref #: February 2018 Page 15

20 hypolimnion, thereby vertically constricting the zone of suitable habitat available to salmonids in the summer. Thus, neither juvenile nor adult steelhead are expected to occupy nearshore waters from June through September. In conclusion, juvenile steelhead may be migrating through or rearing in the action area throughout the year, but would not be expected in the nearshore area where much of the construction would occur after summer lake stratification had occurred. 5 SPECIES IMPACTS The proposed project could potentially affect Chinook salmon, bull trout, and steelhead in generally similar manners, except that as the most closely associated with shallow, nearshore habitats, lake-rearing Chinook salmon fry are likely to experience the greatest effects of the proposed project. Effects may often occur through impacts to habitat, prey base, or physiological effects to individuals. Unless otherwise noted, there will be no distinction between listed salmonids in the following discussion. 5.1 Direct Effects on Salmonids Noise The driving of piles for the new pier will produce temporary noise and vibration resulting from use of the barge, vibratory driver, and other construction equipment. Underwater noise from vibratory driving of piles will be greater than that of other construction equipment. Underwater noise generated from the vibratory pile driving would be expected to be 155 db RMS (CALTRANS 2007). This estimate is based on results from vibratory driving of 12-inch steel piles in numerous marine projects throughout Northern California. Noise would be attenuated to a level below effective quiet and the disturbance threshold for small fish (150 db) at a distance of approximately 72 feet from the project area (WSDOT 2017). In conclusion, noise levels are not anticipated to cause direct injury to salmonids, although fish present within 72 feet of the project activities could display an avoidance response, which could force them away from preferred rearing areas. In order to minimize the impacts on Chinook salmon, bull trout, and steelhead, the above timing restriction (no in-water work would occur from October 1 st through July 15 th ) would be followed. This restriction is adequate to minimize the probability that those species would be in the action area during construction. By constructing during the approved work window, noise impacts are rendered insignificant and discountable. Shallow Water Habitat Shallow water habitat can provide refuge and foraging habitat for juvenile salmonids. Field observations found that during the period from mid-february to mid-april, juvenile Chinook salmon rear along shorelines less than 1.6 ft depth. Juvenile Chinook TWC Ref #: The Watershed Company Page 16 February 2018

21 salmon use progressively deeper water habitats in late-april to May ( ft) and into June ( ft) (Tabor et al. 2006). Juvenile Chinook salmon display avoidance behavior of piers. Surface water observations found that upon approaching a pier, juvenile Chinook salmon will move into deeper water and either pass under or swim around the pier (Tabor et al. 2006). Similarly, in acoustic tracking studies, Chinook smolts avoided areas under overwater structures and changed course to move around such structures (Celedonia et al. 2008). The change in light levels associated with piers and other overwater structures may make it difficult for juvenile Chinook salmon to detect predators (Tabor et al. 2006), and salmon predators like smallmouth bass are often associated with pier piles (Celedonia et al. 2008). Potential impacts to shallow water habitat and outmigration will be minimized through the use of an eight-foot-wide, fully grated, fixed pier elevated nearly four feet above the high water elevation and spanning the nearshore 60 feet. Additionally, a narrow (5-foot-wide), fully-grated gangway will extends an additional 50 feet waterward before meeting the first floating dock segment. Potential predator structure is minimized by avoiding the use of piles in the nearshore 50 feet, and limiting the number and size of the steel pilings throughout the project area. In conclusion, potential impacts to nearshore habitat will be minimized through design of an elevated, fully grated, fixed-pile pier in the nearshore 60 feet, and by positioning the closest floating dock segment nearly 100 feet from the OHWM. Given that neither juvenile nor adult Chinook salmon would be expected in the vicinity of the project area in the majority of the work window and the minimization measures proposed, the effects of the project on habitat are expected to be insignificant. Water Quality A concrete walkway is proposed at the approach to the dock. Uncured concrete can harm aquatic invertebrates and fish by increasing ph of adjacent waters. The project will avoid potential impacts from exposure to uncured concrete by limiting the concrete work to areas above the OHWM and utilizing best management practices to ensure no concrete enters the water. Excavation and fill along the shore has the potential to generate turbidity. To minimize construction impacts associated with increased turbidity and the potential to release toxic chemicals during construction, timing restrictions and erosion and turbidity minimization measures will be implemented, as described in Section 1.4. Construction will disturb the benthic substrate within the immediate project area during the implementation of the project. This disturbance will be limited to the area immediately surrounding each pile and significant turbidity is not expected to result from installation of the pier. Although turbidity can have positive effects on salmon bioenergetics and predator avoidance (Gregory 1994, Mazur and Beauchamp 2003, Mazur and Beauchamp 2006), turbidity is generally considered detrimental because of potential lethal and sub-lethal effects of abrasive suspended sediments (Newcombe and The Watershed Company TWC Ref #: February 2018 Page 17

22 MacDonald 1991). Boat activity in or adjacent to vegetated shallows has been documented to damage and/or destroy vegetated shallows (Fonseca et al. 1998). As stated above, the barge would not be permitted to ground. Significant turbidity is not expected to result from installation of the dock, gangway, or the upland walkway. The most effective strategy for minimizing or eliminating potential construction-related impacts would be to restrict construction to periods when the presence of Chinook salmon, bull trout, and steelhead is improbable. As described in Section 1.4 the project proposes an in-water work window of July 16 th to September 30 th. This window is adequate to minimize the probability that Chinook salmon, bull trout, or steelhead would be in the action area during construction. Thus, temporary water-quality impacts associated with the proposed project are unlikely to result in the take of a listed or candidate fish species. Overwater Structures Juvenile Chinook salmon in Lake Union and the Lake Washington Ship Canal tend to avoid the area underneath overwater structures (Celedonia 2011). A hydroacoustic tagging study found that Chinook salmon smolts frequently occur within approximately 66 feet of the edges of overwater structures in waters greater than 18 feet (Celedonia et al. 2011). Researchers hypothesized that juvenile Chinook salmon may avoid areas under overwater structures because of lower light levels beneath the structure, the degree of contrast at the light-dark edge, and width and height of the structure (Celedonia et al. 2008). Celedonia et al. (2011) suggested that the extensive use of the edges of overwater structures may increase the predation risk on juvenile Chinook salmon from smallmouth bass (Micropterus dolomieu), which are commonly associated with in-water and overwater structures (Fresh et al. 2003). In particular, smallmouth bass are most abundant around large structures with a large number of pilings (Fresh et al. 2003). Shading from the proposed dock and gangway within the nearshore 100 feet has been minimized through to the elevated fixed-pile pier and the fully grated gangway. To the extent that juvenile salmon occur in deeper waters beneath the floating dock segments, effects to their migratory behavior have been minimized through partial grating. The size of the structure and number of pilings proposed has the potential to affect the distribution of small mouth bass. The size and number of pilings have been minimized, and they only occur beyond 50 feet from the OHWM. However, even if smallmouth bass redistribute in association with the proposed new overwater stucture, the net effect on salmonid predation in Lake Sammamish would not be expected to change. Direct Mortality The potential to kill Chinook salmon, bull trout, or steelhead exists as long as they are present in the action area during construction activities. In order to minimize the project impacts on these salmonids, the previously stated timing restriction (no in-water TWC Ref #: The Watershed Company Page 18 February 2018

23 construction at a minimum from October 1st through July 15 th ) would be followed. This restriction is adequate to minimize the probability that salmonids would be in the action area during construction activities such that potential for direct mortality is discountable. 5.2 Indirect Effects on Salmonids Indirect effects include those impacts that occur later in time and may affect habitat quality and availability and foraging conditions for juvenile salmonids and salmonid prey at the shoreline. Water Quality Rigid-stemmed vegetation helps filter nutrients and contaminants from upland runoff, contributing to improved water quality conditions in the lake over time. The proposed project will increase the density and aerial coverage of vegetation along Issaquah Creek, potentially resulting in modest improvements to water quality. Issaquah Creek is a spawning ground for Chinook salmon, which may occur within the Action Area. Habitat Vegetation will be installed upland of the previous mitigation area, which is immediately adjacent to the Lake Sammamish shoreline. The planting area is also in the riparian zone of Issaquah Creek. As the vegetation matures, detritus and terrestrial insect input from the overhanging vegetation will eventually increase allochthonous food supply for juvenile salmon. The vegetation will also provide natural shading of the stream channel, contribute to instream complexity, and provide filtration of pollutants. Thus, the implementation of this shoreline restoration will likely improve habitat conditions for juvenile and adult salmonids in the action area. 6 CRITICAL HABITAT 6.1 Chinook Salmon A final critical habitat designation was formalized for Puget Sound Chinook salmon on 12 August 2005 (Federal Register), specifically including Unit 10, the Lake Washington sub-basin. However, Lake Sammamish and its corresponding watersheds were excluded from this final critical habitat designation. Accordingly, potential effects to the critical habitat for Chinook salmon will not be discussed in this section. 6.2 Bull Trout Critical habitat was designated for Coastal Puget Sound bull trout on 26 September 2005 (Federal Register), specifically including the Lake Washington Critical Habitat Sub- Unit. However, Lake Sammamish was excluded from this critical habitat designation. The Watershed Company TWC Ref #: February 2018 Page 19

24 Accordingly, potential effects to the critical habitat for bull trout will not be discussed in this section. 6.3 Steelhead Critical habitat was recently designated for Puget Sound steelhead on 24 February 2016 (Federal Register), however, the designation excludes the Lake Sammamish watershed. Accordingly, potential effects to the critical habitat for steelhead will not be discussed in this section. 7 CUMULATIVE IMPACTS Cumulative impacts were assessed through the review of site plans, an aerial photo, and background information from various sources. The proposed project implements an element of the Lake Sammamish State Park Redevelopment and Restoration Concept Plan (Washington State Parks 2007). In addition to the proposed project, upland components to the Park Plan for the Sunset Beach area include irrigation improvements for the turf grass, new picnic shelters, new playground equipment, and replacement of the existing bathhouse and concession facility with a new building with a green roof. In addition to park improvements at Sunset Beach, the Plan highlights proposed infrastructure and facility improvements throughout the park area. The Plan highlights how natural features will be protected in each of the park areas, and any park improvements will require permitting from applicable local, State, and Federal agencies. Therefore, cumulative impacts on sensitive fish and wildlife species and their habitats are not considered significant. 8 DETERMINATION OF EFFECT Several measures of the proposed project will be implemented to avoid, minimize, and offset potential impacts. These include: timing the project to occur during a period when listed salmonids are least likely to be present in the action area and implementing measures to minimize habitat disturbance. Because these measures will be implemented, potential effects of the proposed project are expected to be insignificant or discountable, as described in Section 5. Therefore, given the direct, indirect, interrelated, and interdependent effects from the proposed action, the proposed project may affect, but is not likely to adversely affect, Chinook salmon, bull trout and steelhead. Species specific effect determination details are provided below. TWC Ref #: The Watershed Company Page 20 February 2018

25 8.1 Chinook Salmon The project may affect Puget Sound Chinook salmon because: Chinook are documented in Lake Sammamish. Juvenile Chinook salmon are likely to migrate through or rear in the action area from January through June, and adult Chinook salmon may be in the action area from late August to November. The project is not likely to adversely affect Puget Sound Chinook salmon because: 8.2 Bull Trout In-water work will be limited to a work window when Chinook salmon are least likely to be present in the Action Area. Habitat impacts will be minimized by using fully grated decking for light transmission, an elevated fixed-pile pier and a narrow gangway in the nearshore, and limiting the number and size of supportive steel pilings used. Native vegetation will be planted adjacent to Wetland B near the Lake Sammamish shoreline. The project may affect Coastal-Puget Sound bull trout because: Coastal-Puget Sound bull trout are documented as occurring in Lake Sammamish. Therefore, though unlikely, bull trout could be present within the action area. The project is not likely to adversely affect Coastal-Puget Sound bull trout because: Bull trout presence in the action area is highly unlikely anytime during the year, and in particular, bull trout would not be expected to occur in the project vicinity from late spring to fall. In-water work will be limited to a work window when bull trout are least likely to be present in the Action Area. Habitat impacts will be minimized by using fully grated decking for light transmission, an elevated fixed-pile pier and a narrow gangway in the nearshore, and limiting the number and size of supportive steel pilings used. Native vegetation will be planted adjacent to Wetland B near the Lake Sammamish shoreline. The Watershed Company TWC Ref #: February 2018 Page 21