Mercer Creek Floodplain and Riparian Restoration
About the Project
Mercer Creek is part of the Wilson Creek system, carrying both natural water flow and irrigation returns. Mercer Creek separates from Wilson Creek approximately 11 miles northeast of Ellensburg. It travels through agricultural areas, the urban fringe area of northern Ellensburg, and then through the City of Ellensburg proper before rejoining Wilson Creek at the City's southwest edge, 2 miles downstream of the project area.
The Mercer Creek Riparian Restoration project, located along 1,200 ft of Mercer Creek between Airport Road and East Helena Avenue in Ellensburg, aims to enhance floodplain and riparian habitat. Streamside (riparian) areas perform key functions for society and for the environment: stabilizing sediments and filtering water, providing temperature-moderating shade, creating a base in the food-web for insects eaten by fish and wildlife, and slowing and spreading water during flooding to reduce erosion and flooding downstream. This project builds on previous efforts elsewhere on Mercer Creek to improve water quality, increase riparian habitat, and reduce flooding. The project includes four private landowners and a parcel owned by Kittitas County.
Restorative Actions
MCF, with our partners at the Kittitas County Flood Zone Control District, City of Ellensburg, and Washington Department of Fish and Wildlife, completed construction of an inset floodplain in 2021 and revegetated the site using native riparian species. Seasonal high flows are expected to be contained in the new, recontoured floodplain, and native riparian trees and shrubs were planted. The benefits of inset floodplains include improved groundwater infiltration, floodplain function, and fish and wildlife habitat. Native woody vegetation will increase shading of the creek and remove more pollutants and sediment from stormwater.
This project will benefit water quality and reduce flood risk. MCF provides opportunities annually to get involved in the project with hands-on volunteer activities during planting and stewardship.