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Dungeness Flow Restoration and Aquifer Recharge Off-channel Reservoir Project


Brief Project Description:  Low flow in the Dungeness River is a significant limiting factor for four ESA-listed species of Salmon and Steelhead. Low flows are primarily a seasonal challenge, occurring in the late summer and early fall.  Around mid to late August, human needs for irrigation water peak, Chinook and Pink salmon return to spawn, the snowpack feeding the river is depleted, and the river drops to its lowest flow.  In all but the wettest years with ample snowpack, these low flows are insufficient to meet the needs of salmon. The biggest and most senior established water rights in the basin belong to the Dungeness irrigators.  For more than a century the Dungeness Valley has been irrigated with water directly from the Dungeness River.  In the last 20 years Dungeness irrigators and basin partners have invested considerable resources to conserve and enhance flow in the River.  However, in low snowpack years there is still not enough flow in the river to support salmon and also meet out-of-stream water needs.  The solution is an off-channel reservoir to store water during winter and spring when flows are plentiful, saving this water for later in the year when river flow is low.  In addition to resulting in significantly higher low-flow levels, this is a multi-benefit project that will capture stormwater and prevent flooding in the City of Sequim, provide opportunities for aquifer recharge, create a new County park with river access and recreational opportunities, and ensure the sustainability of agriculture in the Dungeness Valley – all providing climate resiliency for people, farms, and fish.

View a video showing how the off-channel reservoir will operate to enhance water supplies and provide climate resiliency for people, farms, and fish.  Listen to the multiple benefits of the project.  Download the Fact Sheet for more detailed information.

Conceptual Rendering Dungeness Off-stream Reservoir

Reservoir Size:  88-Acre reservoir within a new 396-Acre County Park

Storage Capacity: 1500 acre feet, enough to retain about 25 cubic feet per second (cfs) for use during critical low-flow period of Aug 15th-Sept 15th (the last month of irrigation season) when flows before diversions are often less than 100 cfs

Community Benefits:

--Stream Flow Restoration For Salmonids  The project will retain up to 25 cfs of flow in the Dungeness River by avoiding diversions, allowing the target flow-restoration goal of 105 cfs to be met, benefiting ESA-listed Salmon and Steelhead.

--Stormwater Management  The project will alleviate flooding on roads and properties in the County and City of Sequim by intercepting storm flows before they reach infrastructure and pollution-generating urban areas.

--Aquifer Recharge  In years with adequate snowpack, stored winter runoff can be used for aquifer recharge that will augment flows in small streams and possibly generate mitigation credits for the Dungeness Water Exchange.

--Long-Term Agricultural Viability  Secure access to water for irrigation is critical to maintaining agriculture in the Dungeness Valley; this project will ensure that fish can thrive and irrigation can continue without impacting flows.

--Recreation  The project site is currently owned by Department of Natural Resources and will be eventually owned and managed by Clallam County as a new public park with hiking, biking, wildlife viewing, and river access opportunities.

--Climate Resiliency  Decreasing water supplies is the biggest climate concern for the region and this project provides a solution for salmon and agriculture during drought years and for drinking water supply/aquifer stability over time.

Status, Summer 2018:  Preliminary Design complete, Cost Benefit Analysis complete.  Funding applications: Floodplains by Design, Salmon Recovery Funding Board, Puget Sound Acquisition and Restoration Fund, FEMA Hazard Mitigation Grant, Puget Sound Partnership Near Term Action (Action Agenda); DNR-Clallam County Trust Land Transfer.

Partners:  Clallam County, City of Sequim, Dungeness Valley Irrigators, Clallam Conservation District, Washington Water Trust, and Jamestown S’Klallam Tribe

Supporters include Washington Dept’t of Fish and Wildlife and Washington Dep’t of Natural Resources

For More Information Contact:  Jason Hatch, Project Manager, ; 360.328.3166 or Carol Creasey, Clallam County Hydrogeologist, ; 360-417-2424