5900 36TH AVE W SEPA 015 - 034 - SOUNDVIEW BUSINESS CAMPUS - VERITAS Land Use Decision Documents 2025-04-22

listed as hydric, the predicted inclusions of Terric Medisaprists, McKenna, and Norma soils are listed as hydric on the Washington State Hydric Soils List. Alderwood-Everett gravelly sand, loam oam is on till plains, terraces, and outwash plains. This unit is about 60 percent Alderwood gravelly sandy loam and about 25 percent Everett gravelly sandy loam. Included in this unit are small areas of Ragnar, Indianola, McKenna, and Norma soils and Terric Medisaprists in depressional areas and drainageways on plains. Also included are colluvial soils, slump areas, and escarpments. 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. Depth to the hardpan ranges from 20 to 40 inches. Permeability of the Alderwood soil is moderately rapid above the hardpan and very slow through it. A seasonal perched water table is at a depth of 18 to 36 inches from January to March. Springs or seep areas are common. Although Alderwood-Everett gravelly sandy loam is not listed as hydric, the predicted inclusions of Terric Medisaprists, McKenna, and Norma soils are listed as hydric on the Washington State Hydric Soils List. 3.1.3 Hydrology Criteria As stated in the 2010 Regional Supplement, the "term wetland hydrology encompasses all hydrologic characteristics of areas that are periodically inundated or have soils saturated to the surface for a sufficient duration during the growing season." It also explains "areas with evident characteristics of wetland hydrology are those where the presence of water has an overriding influence on characteristics of vegetation and soils due to anaerobic and chemically reducing conditions, respectively." Additionally, the US Army Corps of Engineers 1987 Wetland Delineation Manual states that "areas which are seasonally inundated and/or saturated to the surface for a consecutive number of days >_ 12.5 percent of the growing season are wetlands, provided the soil and vegetation parameters are met. Areas inundated or saturated between 5 and 12.5 percent of the growing season in most years may or may not be wetlands. Areas saturated to the surface for less than 5 percent of the growing season are non -wetlands." Field indicators were used to determine whether wetland hydrology parameters were met on this site. Critical Area Study 5 WRI# 15202 Soundview Business Campus Rev. #2: October 2, 2015