WA ST Dept of Ecology 8/21/2022 - Laserfiche WebLink

DocuSign Envelope ID:478DAF06-A27F-4277-9842-A0AA8B37CB3D State of Washington Department of Ecology Page 2 of 43 Agreement No: WQC-2022-EverPW-00084 Project Title: 100th St.SW Regional Stormwater Facility Study Recipient Name: City of Everett Currently much of the corridor consists of a two-lane road with little to no shoulder facilities. The road has no stormwater treatment and the surrounding area has limited treatment that is not up to current standards. The RECIPIENT has procured a Puget Sound Regional Council (PSRC)Grant to widen the corridor to provide appropriate vehicle travel lanes and to construct new bicycle lanes and sidewalks. This PSRC grant will provide funding for stormwater treatment facilities for the new impervious road surfaces to the extent required by state and local stormwater standards. The ECOLOGY-funded portion of this project will design expanded stormwater best management practices to mitigate stormwater runoff from existing hard surfaces. The roadway project extends across much of the upper reaches of the Swamp Creek Basin,a water body with degraded water quality and streamflow concerns. Swamp Creek has a fecal coliform bacteria(Total Maximum Daily Load(TMDL)and urban stormwater was identified as one of the primary contributing sources. Land use in the 100th Street SW corridor generally consists of medium density single family and multifamily residential development. Some parcels remain undeveloped and narrow corridors along portions of the stream remain forested. The area is one of the more rapidly developing areas within the city with eight active development applications touching the 100th Street SW corridor. It is likely that the road widening will continue to drive infill development. Available sites for stormwater improvements currently exist,but may be lost as infill continues. This project would allow the RECIPIENT to explore ways to create regional stormwater facilities that would not only serve the proposed roadway improvements,but also runoff from existing development. The 100th street corridor reaches across four distinct sub-basins and stormwater treatment would require at least two facilities. The RECIPIENT has identified potential sites for the two facilities. One facility would treat runoff from approximately 21.7 acres of land in the west sub-basin including about 2.4 acres of new impervious surface added by the roadway project. The second facility,on the eastern end of the corridor,concept level plans indicate that a proposed regional site could treat approximately 25.1 acres, including 0.5 acres of new impervious surface added by the road widening. ECOLOGY funding will be used to fund design of stormwater treatment of existing road surface. As part of the facility selection process the RECIPIENT will explore the opportunity to oversize the facility to accommodate future development, with the understanding that ECOLOGY will not fund the design of capacity for new development. A secondary benefit of this stormwater facility selection and design project will be to demonstrate the value of looking at infrastructure improvement projects as an opportunity for water quality improvement. It will encourage internal and external stakeholders to shift thinking away from project-by-project stormwater mitigation efforts to more regional type facilities. Larger facilities collecting runoff from existing areas as well as new projects will provide a net improvement to water quality while reducing stormwater mitigation costs to projects. Overall Goal: This project will help protect and restore water quality in Washington state by reducing stormwater impacts from existing infrastructure and development. Template Version 12/10/2020