4800 DOGWOOD DR 2022-02-28 - Laserfiche WebLink

Pursuant to EMC 19.37.110(B)(1), increased standard buffer widths are required when the minimum buffer for a wetland extends into an area with a slope of greater than twenty-five percent. In this case, the buffer shall be the greater of a) the minimum buffer for that particular wetland; or b) twenty-five feet beyond the point where the slope becomes twenty-five percent or less for at least a horizontal distance of ten feet. The wetland buffer extends into an area with a slope greater than twenty-five percent and the buffer has been expanded accordingly. Pursuant to EMC 19.37.110(A)(7), to maintain the integrity of the buffer, buildings and other structures shall be set back a minimum of ten feet from the edges of all wetland boundaries. One feature, a rain garden/bioretention area is located within the 10-foot building and structure setback from the wetland buffer boundary. A rain garden does not qualify as a building or structure as defined by EMC 19.04.010. The proposed rain garden is a low impact stormwater management technique, as described in the Low Impact Development Technical Guidance Manual for Puget Sound (January 2005). This rain garden (planted with native vegetation) will use the chemical, biological, and physical properties of plants, microbes, and soils to remove pollutants from stormwater. 6.0 WETLAND AND STREAM FUNCTIONS AND VALUES ASSESSMENT 6.1 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. 6.2 EXISTING CONDITIONS The on-site wetland rates low to moderate for water quality and hydrologic functions and values based on the 2014 Wetland Rating System. Vegetation in the wetland has the ability to trap sediments and pollutants providing water quality function, but this function is limited by the fact that the wetland has a greater than 5% slope. The wetland also has limited opportunity to provide water quality and hydrologic value as it is not associated with areas where water quality or flooding is problematic. The wetland provides a moderate level of habitat function. The wetland is forested and contains vegetation in the shrub and herbaceous layers. It contains important habitat features such as large, downed woody debris and standing snags. The View Ridge Community Church 7 Critical Area Report and Buffer WRI#16092 Averaging/Enhancement Plan November 21, 2016