9307 18TH AVE W 2025-04-18 - Laserfiche WebLink

Alderwood Urban land complex is described as about 60 percent Alderwood gravelly sandy loam and about 25 percent urban land. Included in this unit are small areas of McKenna and Norma soils and Terric Medisaprists in depressional areas and drainageways on plains. Also included are small areas of soils that are very shallow over a hardpan; small areas of Everett, Indianola, and Ragnar soils on terraces and outwash plains;and soils that have a stony and bouldery surface layer. Included areas make up about 15 percent of the total acreage. The Alderwood soil is moderately deep over a hardpan and is moderately well drained. It formed in glacial till. Typically the surface layer is very dark grayish brown gravelly sandy loam about 7 inches thick. The upper part of the subsoil is dark yellowish brown and dark brown very gravelly sandy loam about 23 inches thick. A weakly cemented hardpan is at a depth of about 35 inches. Permeability of this soil is moderately rapid above the hardpan and very slow through it. Available water capacity is low. Except for where minor components exist, this soil unit is not listed on the Washington State Hydric Soils List. 2.2.3 Hydrology Criteria The 2010 Regional Supplement defines wetland hydrology as "areas that are inundated (flooded or ponded) or the water table is less than or equal to 12 inches below the soil surface for 14 or more consecutive days during the growing season at a minimum frequency of 5 years in 10." During the early growing season, wetland hydrology determinations are made based on physical observation of surface water, a high water table, or saturation in the upper 12 inches. Outside of the early growing season,wetland hydrology determinations are made based on physical evidence of recent inundation or saturation (i.e. water marks, surface soil cracks,water-stained leaves). 3.0 BOUNDARY DETERMINATION FINDINGS Wetlands and streams in the site vicinity were classified according to the Cowardin System, as described in Class f cation of Wetlands and Deepwater Habitats of the United States(Cowardin et al., 1979), and according to the Hydrogeomorphic (HGM) Classification System (Brinson 1993). Wetlands were rated using the DOE Wetland Rating System for Western Washington: 2014 Update (Hruby 2014). Streams were classified according to the state water typing rules found in the Washington Administrative Code (WAC) 222-16-030. Protective buffers are assigned to wetlands and streams based upon these classifications, as shown under EMC 19.37.110 and 19.37.170, respectively. 3.1.1 Stream A: Swamp Creek HGM Class: Riverine Cowardin Classification: Riverine, Upper Perennial, Unconsolidated Bottom, Mud Stream Classification (WAC 222-16-030): Type F Buffer: 150 feet City of Everett depicts Stream A as Swamp Creek, within the upper Swamp Creek sub-basin (WRIA 8). Stream A flows south along the eastern property boundary. The stream channel enters the site from associated Wetland A,and exits the site via a culvert under 93rd Place SW.All physical characteristics of the on-site stream reach meet the water-typing rules for a Type F stream. In the city of Everett, Type F streams with degraded buffers receive 150-foot protective buffers (EMC 19.37.170(A)(3)). Talley - 18th Ave W 4 Critical Area Study and Buffer Restoration Plan WRI#19238 November 6, 2019