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3.0 WETLAND FUNCTIONS AND VALUES ASSESSMENT Pursuant to requirements set forth in MMC 17.52B.140 critical areas reports shall assess the impacts of any alteration proposed for a critical area or buffer. The following assessment is intended to compare the current and post-development functions and values provided by Wetland A in the vicinity of the project area. 3.1 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 system, but is typical for assessments of similar systems common to Western Washington. 3.2 FUNCTIONAL COMPONENTS Wetlands in Western Washington perform a variety of ecosystem functions. Included among the most important functions provided by wetlands are stormwater control, water quality improvement, fish and wildlife habitat, aesthetic value, recreational opportunities and education. The most commonly assessed functions and their descriptions are listed below. 3.3 VALUE ASSESSMENT 3.3.1 Wetland A Hydrologic Function Wetland A is a slope wetland. In general, wetlands in depressional areas with limited outlets store greater amounts of water than wetlands with unrestricted flow outlets. This wetland collects and temporarily stores precipitation as well as runoff from the surrounding area during storm events. However, the wetland's sloped nature reduces the potential residence time of water within the wetland. Due to its geomorphic position on a slope, this wetland provides a low to moderate value for this function. Water Quality This wetland provides some water quality benefits as water moves through the system. Since this wetland is on a slope, the residence time in this wetland is fairly low. Small ponded areas within slope wetlands allow sediments to drop out of suspension, thereby increasing water quality. Vegetation also allows this wetland to perform a bio-filtration function. This area contains dense cover of persistent forest and with a scrub-shrub layer present. Residence time and vegetation allow this wetland to provide a moderate value for this function, however its position on a slope greater than 2 percent limits the wetland's potential to perform a high water quality function. Wildlife Habitat Wetland A is quite small and as such has limited potential to provide a significant wildlife habitat function. The wetland has low structural complexity and is composed of forested vegetation. There is low species diversity and large amounts of invasive species that restrict wildlife use. Additionally, there is only one hydroperiod across the site, with no areas for significant live Mundorf-8th St 11 Critical Area Study & WRI#16233 Mitigation Plan March 2016