9424 18TH AVE W 2018-01-02 MF Import

SECTION IV - Analysis 8� Design Of Erosion And Sedimentation Control BMPs Erosion and sedimentation control during construction will be accomplished primarily by silt fencing along the border of the wetland buffer (see TESC plans). The compost filter berms wili be constructed in the first phase of the project to mitigate, and treat if necessary, any flows from the construction site. Water quality will be ensured by application of appropriate BMPs inciuding silt fencing, interceptor trenches, etc. Stabilization of disturbed soils will minimize transpoft of sediment, thereby reducing the effort required to intercept sediment in motion. Double silt fences will be employed to dramatically minimize the risk of sediment-laden waters leaving the construction zone. The water intercepted by the siit fence will infiltrate into the native soils. The previously mentioned compost filter berms will provide long-term water quality mitigation after the project is complete. Please see attached TESC plans for furthe� information. SECTION V- Analysis � Design of Runoff C�ntrol Runoff management will employ low impact development techniques to attenuatz and mitigate runoff volumes. The methods used are based upon Best Management Practices contained in Volume Ilt and V of the 2005 DOE StormwaterMan.agement Manual for Western Washington and the Low-impact Development Technrcal Guidance Manual for Puget Sound published by the Puget Sound Action Team. The following analysis and summary confirms that the propo•ad low-impact development methods accomplish the intent of the City of Everett codes. PROPOSED DEVELOPED CONDITIONS The developed site includes sixteen single-family detached residential uiiits with assoc�ated roadway and utilities. A seventy-five foot buffer is proposed between the wetland and the homes. Dispersion pad, rain gardens and compost-filter b�rms wili be constructed within or adjacent to tl�is buffer. The surface water runoff from the Centrai Core wili be collected and directed to a series of rain gardens. Ultimately the system of compost berms provides additional storage and treatment for runoff that exceeds the storage capacity of the rain gardens. Runoff from downspouts and footing drains will be absorbed into the soii and/or discharged to the buffer area for dispersion. HEARTHSTONE LANE 5 DRAINAGF_ REPORT APR/L 2006