In 2012 the City of Mukilteo developed a Watershed-based Stormwater Strategies Plan. The city developed priorities and completed many projects based on this plan. The projects are meant to decrease erosion in gulches, help wildlife habitat and reduce harmful high stormwater flows. This will improve the health of streams and the Puget Sound.
The Stormwater Strategies Plan improved understanding of the negative impacts caused by altered hydrology. It also identified basins where implementing Low Impact Development (LID) would be most effective.
The 2013 Stormwater Strategies Plan is based on how watershed processes change in relation to the stream’s position on the landscape. In Mukilteo, plateau areas are important for storage and recharge. Bluff areas and ravines are important for recharge and discharge. Recharge processes are an important component to preserving and restoring watersheds. Groundwater movement influences these processes, especially in the plateau areas. However, groundwater movement is not well understood in Mukilteo. Because of this, the Strategies Plan was unable to use recharge as part of the analysis.
The Stormwater Strategies Plan analyzed watersheds in the City and the surrounding area. The Strategies Plan refined the method in Washington State Department of Ecology’s “Puget Sound Characterization” (Stanley et al. 2011). The Characterization established a framework to evaluate watershed processes. Recommendations for preservation, retrofits, and other stormwater management methods were made. The recommendations were prioritized based on the evaluation of the watershed processes. This Plan identified the Picnic Point Ravine, Big Gulch North, and Big Gulch South PAUs as high priority for stormwater retrofits.
In 2014 the City continued the work of the Watershed-based Stormwater Strategies Plan and developed a Stormwater Retrofit Plan. This work was funded through a grant from the National Estuary Program (NEP) Watershed Protection and Restoration Grant Program. In 2015, a Pre-Design report was completed, followed by installation and design of several projects.
Along with the Department of Ecology, the city partnered with the City of Everett, Snohomish County Paine Field Airport, Snohomish Conservation District and Mukilteo School District on the project. Technical assistance was provided by ESA, an environmental science and planning firm, and Silver Tip Solutions, a Mukilteo-based environmental consulting firm specializing in multi-scale watershed assessment.