10104 DAKOTA WAY 2022-01-31 - Laserfiche WebLink

"Native existing and volunteer species may be included to meet native species cover requirements. 16.0 WETLAND AND STREAM ]FUNCTIONS AND VALUES ASSESSMENT 16.1 METHODOLOGY The methodology for this functions and values assessment is based on professional opinion developed through past field analyses and interpretation. This assessment pertains specifically to the on -site wetland and stream, but is typical for assessments of similar systems common to western Washington. Functions and Values Components Wetlands in western Washington perform a variety of ecosystem functions. Included among the most important functions provided by wetlands are stormwater storage and flood flow attenuation, water quality improvement, and fish and wildlife habitat. An assessment of these functions for the project site is provided below. Streams provide both hydrologic and habitat connections throughout the Western Washington Region. Many channels serve as rearing grounds for a variety of fish species, including salmonids. Many wildlife species make use of the resources provided by riparian ecosystems. 16.2 EXISTING CONDITIONS The on -site wetlands have limited potential to provide water quality functions, as the slope of these wetlands is greater than 5 percent and they do not contain a significant amount of dense, uncut herbaceous or woody vegetation to trap sediments and pollutants. However, because they are located in a developed area that generates pollutants and there are water quality issues identified downstream of the site, the water quality function provided by the on -site wetlands is valuable. Hydrologic functions provided by the on -site wetlands are also limited by the lack of dense, uncut rigid vegetation that could slow the flow of surface water. However, the hydrologic functions these wetlands do provide are important as the surrounding area contains development that generates excess runoff and flooding problems occur down -gradient of the site. Wetland A is composed of forested habitat that contains multiple vegetation strata, which provides thermal and hiding cover in close proximity, nesting and perching opportunities, and food sources that benefit wildlife. Vegetation in Wetland B includes maintained lawn as well as forest with multiple strata. The maintained lawn area provides very little wildlife habitat function. The forested area provides thermal and hiding cover, nesting and perching opportunities and forage resources that benefit wildlife. Wetland C includes a forested canopy with mainly herbaceous vegetation below. The trees provide nesting and perching opportunities as well as some amount of thermal and hiding cover. The herbaceous vegetation, which is includes creeping buttercup (Ranunculus repens), skunk cabbage (Lysichiton americanus), lady fern (Athyrium cyclosorum), and field horsetail (Equisetum arvense) provides limited habitat function, but may support some small mammals. Wetlands A and B contain large woody debris and standing snags that are important to certain wildlife species. APV Ventures LLC—Dakota Way 22 Critical Area Report, Buffer Mztigation WRI #20015 Plan & Habitat Assessment April27, 2020