2320 106TH ST SW 2025-07-21 - Laserfiche WebLink

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. Hydrology Criteria The manual states: "Wetland hydrology indicators are used in combination with indicators of hydric soil and hydrophytic vegetation to determine whether an area is a wetland under the Corps Manual. Indicators of hydrophytic vegetation and hydric soil generally reflect a site's medium- to long-term wetness history. They provide readily observable evidence that episodes of inundation or soil saturation lasting more than a few days during the growing season have occurred repeatedly over a period of years and that the timing, duration, and frequency of wet conditions have been sufficient to produce a characteristic wetland plant community and hydric soil morphology." Field indicators are used for determining whether wetland hydrology parameters are met. BOUNDARY DETERMINATION FYNDINGS Wetland A Dominant vegetation within the area mapped as Wetland A is characterized by the presence of the following species: salmonberry (Rubies spectabilis, Fac), Himalayan blackberry (Rubus armeniucus, FacU), reed canarygrass (Phalaris arundinacea, FacW), and creeping buttercup (Ranuncrdus repens, FacW). The underlying soils are typically black (IOYR 2/1) silt loam from 0-6 inches and very dark gray (10YR 3/1) silt learn with 10% dark yellowish brown (10YR 3/4.) redoximorphic features from 6-18 inches. The soils were saturated below 6 inches during our May 11, 2015 site visit. The dominance of species rated "Facultative" or wetter meets the criteria for hydrophytic vegetation in the areas mapped as wetland. Based on field indicators of hydric soils, it appears that the areas mapped as wetland are saturated to the surface for more than 12.5 percent of the growing season, thereby fulfilling wetland hydrology criteria. Wetland B Dominant vegetation within the area mapped as Wetland B is characterized by the presence of the following species: red alder (Alms rubra, Fae), hardhack (Spirea douglasii, FacW), ISentucky bluegrass (Poa pratensis, Fac), and creeping buttercup (Ranunculus repens, Facw. The underlying soils are typically very dark brown (IOYR 2/2) silt loam from 0-6 inches and dark grayish brown (1 OYR 4/2) sandy loam with 10% brown (10YR 4/3) redoximorphic features from 6- 18 inches. The soils were saturated below 6 inches during our May 11, 2015 site visit. The dominance of species rated "Facultative" or wetter meets the criteria for hydrophytic vegetation in the areas mapped as wetland. Based on field indicators of hydric soils, it appears that Critical Area Study and Buffer Averaging Plan March 16, 2016 C & D Land Co. 1061h Street SW 4 WRI #15111