4931 SEAHURST AVE 2016-01-01 MF Import

WETLAND FUNC710NS AND VALUES ASSESSMENT Methodology: The methodology for this functions and values assessment is based on professional opinion developed through past field anaiyses and interpretations. This assessment pertains specifically to the on-site wetland systems, but is typical for assessments of similar systems throughout western Washmgton. Analysis: The wetland associated with Seahurst Glenhaven Creek provides functions to the surrounding environment such as hydrologic control, water quality, and wildlife habitat. Based on its physical characteristics, the subject wetland provides a moderate level of functions and values. Hydrologic control (Flood control and water supply) is an important function provided by wetlands. Due to their depressional charaderistics, wetlands effectively function as natural water storage areas during periods of high precipitation and are able to accumulate stormwater runoff. Wetlands with limited outlets store greater amounts cf water than wetlands with unrestricted flow outlets. Forested wetlands retain more stormwater and help prevent soil erosion through hydrologic flows. Wetiand vegetation heips to slow and store stormwater. Because this wetland is associated with a stream, has rigid, �nroody veget��tion, and small depressions to trap water and sediment, it has the potential to create a valuabte, natural water-retention system. Water quality is closely tied to hydrologic control. Wetlands are areas into which floodwaters spread during periods of high precipitation. As water flows through the wetland, it is slowed by vegetation and the sediment settles to the bottom before the water moves further downstream. Suspended soils in the water may be removed by the wetland as the water passes through, resulting in cleaner water entering the downstream system. The depressional and riparian characteristics of the on-site wetland provide a moderate value for this fundion. The suhject wetland provides habitat to many wiidlife species. The following avian species were detected on-site� American robin (Turdus migratorius), black-capped chickadee (Poecile atricapillus), bushtit (Psaltriparvs minimus), house finch (Carpodacus mexicanus), song sparrow (Melo:;piza melodia), and steller's jay (Cyanocitta slellen). Many other wildlife species are expected to use the subject property because the site contains habitat for avian, mammal, and amphibian species. The wetland and associated edges provide movement �orridors which become increasingly important as areas become more developed. Wetlands often contain resources such as food, water, thermal cover, and hiding cover in close proximity, which wildlife species need to thrive. The following are other typical avian species that may utilize this habitat: common raven (Corvus corax), dark-eyed junco (Junco hyemalis), northern flicker (Colaptes aurafus), and winter wren (Troglodytes troglodytes). Mammalian species that may utilize this site include species that easily adapt to suburban environments such as bats (Myotis spp.), black-tailed deer (Odocoileus hemronus columbianus), coyotes (Canis latrans), deer mice (Peromyscus m�niculatus), eastern cottontail rabbits (Sylvilagus floridanus), moles (Scapan�s spp.), mcuntain Johnson- Seahurst Ave. 6 WRl# 11 f02 Cri!ical Area Study September 28, 2011 - �// 9