3815_PGSF WMVD Pkg 2_Vol 4-2_03.03.2026_BXWA_Certified

ASPECT CONSULTING 12 FINAL PROJECT NO. AS190583A-08  MAY 21, 2025 (Canada lynx, gray wolf, grizzly bear, marbled murrelet, and northern spotted owl) are all associated with habitat that includes large undeveloped areas, which do not occur on or near the Upland Area. Based on the Washington Nature Mapping Program, potential habitat for these five species, and critical habitat for the northern spotted owl and marbled murrelet, is not present within 20 miles of the Upland Area. Many of the twelve ESA-listed aquatic species identified in Snohomish County 3 are known to occur in Possession Sound. However, only a few of the twelve species are likely to occur within the narrow and relatively shallow water of the East Waterway. The marine mammal and sea turtle species (humpback whale, killer whale, Steller sea lion; and leatherback sea turtle, respectively) typically occur in the deep-water habitat of Puget Sound and could occur in Possession Sound offshore of the Upland Area, but are very unlikely to occur in the East Waterway adjacent to it. Chinook salmon, steelhead, and bull trout occur in Possession Sound and are likely to migrate near the East Waterway shoreline. The fish species bocaccio, canary rockfish, green sturgeon, Pacific eulachon, and yelloweye rockfish are associated with deep-water habitats of Puget Sound and typically breed and forage near the ocean floor. Adults of these species are very unlikely in the marine environment of the East Waterway. Juveniles of these species do migrate in nearshore habitats and could occur in the adjacent offshore habitat. Overall, the Upland Area is completely developed with vegetation limited to a narrow patch of landscaped trees, shrubs, and managed grass along a shoreline walking trail. The limited vegetation represents low-quality wildlife habitat. Wildlife use of the terrestrial habitat is likely dominated by disturbance-tolerant species typical of urban areas. The adjacent marine habitat provides foraging habitat for waterfowl and other birds and aquatic species typically found in the marine environment of Puget Sound. Habitat surrounding the Upland Area includes fragmented and disturbed areas associated with industrial development. 2.4.4 Hydrogeology and Groundwater Flow 2.4.4.1 Stratigraphy A wedge of fill, generally thickening from east to west, comprises the shallow subsurface soils across the Upland Area. Beginning in the very late 1800s, fill was placed on the East Waterway tidal flats to create new upland in the northeastern-most portion of the Upland Area, as described in Section 2.2. The vast majority of the Upland Area was created by hydraulic placement of dredged fill predominantly in 1929-1930, with placement of additional fill beneath the current dock structure in 1954. The fill thickness generally ranges from about 15 to 40 feet thick from east to west across the Upland Area (Shannon and Wilson, 2014). Based on extensive subsurface drilling during the Phase 2 ESA and RI, and the IA excavations, the fill has variable composition, predominantly including sand and silty sand showing stratification and containing shell fragments (dredge fill), and localized 3 Chinook Salmon, Puget Sound Steelhead, Bocaccio, Canary Rockfish, Green Sturgeon, Pacific Eulachon, Yelloweye Rockfish, Bull Trout, Orca, Leatherback Sea Turtle, Humpback Whale, and Stellar Sea Lion.