4931 SEAHURST AVE 2016-01-01 MF Import

The foilowing criteria descriptions were used in the boundary determination: Wetland Vegetation Criteria The 1997 edition ot the Washington State Wetlands Identification and Delineation Manual defines hydrophytic vegetation as "the sum total of macrophytic plant life that occurs in areas where the frequency and duration of inundation or soil saturation produce permanently or periodically saturated soils of sufficient duration to exert a controlling influence on the piant species present." Field indicators were used to determine whether the vegetation meets the definition for hydrophytic vegetation. Wetland Soils Criteria and Mapped Description The 1997 edition of the Washington State Wetlands Identi(icafion and Delineation Manual defines hydric soils as "soils that formed under conditions of saturation, flooding, or ponding I� ng enough during the growing season to develop anaerobic conditions in the upper part." Field indicators were used to determine whether a given soil meets the definition for hydric soils. The soils underlying. the project area are mapped in the Soil Sun�ey of Snohomish County Area Washington as Alderwood Urban land complex, 8 to 15 percent. Aldervvood Urban land complex, 8-15 percent slopes: This unit is 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 �epressional 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 Aldenvood 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. Wetland Hydrology Criteria: The 1997 edition of the Washington State Wetlands Identification and Delineation Manua! states that lhe "term wetland hydrology encompasses all hydrologic characteristics of areas that are periodically inundated or have soils saturated lo the surfac� for a sufficient duration during the yrowing season." It also explains that "areas with evident characteristics of wetland hydrology are �hose where the presence of water has an overriding influencr_ on characteristics of vegetation and soils due to anaerobic and chemically reducing conditions, respectively." Additionaliy, the manual states that "areas which are seasonally inundated andlor saturated to the surface for a consecutive number of days ?12.5 Fercent rf the gro�ving season are K�etlands, provided the soil and vegetation parameters are met. Areas inundated or saturated beriveen 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 Johnson - Seahurst Ave. 3 WRI# 11102 Critical Area Study September 28, 2011 �^ s��y