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Water Stargrass Management

Keeping the Yakima River Safe for Salmon & Our Communities

Benton Conservation District (BCD) is leading the effort to manage overgrowth of water stargrass. Although a native plant, water stargrass acts like an invasive species dominating the lower river to the exclusion of other native plants. The dense vegetation creates challenges for irrigation and recreation, degrades water quality and fish habitat, and enhances breeding grounds for disease-carrying mosquitoes.

Challenges of Water Stargrass

Water stargrass is a perennial plant that forms a dense two-inch thick mat of roots. When salmon return to the lower Yakima River to spawn, they find their traditional nesting grounds covered by stargrass, and they are forced to migrate further. Water stargrass has steadily increased over the last decade, causing salmon spawning in the lower river to decrease.

During the day, water stargrass produces oxygen. After the sun goes down, water stargrass consumes more oxygen than it produces, and sometimes causes dangerous drops in the amount of oxygen available to fish and other aquatic life. Water stargrass has become so thick that anglers, boaters, hunters, swimmers and other recreationists can't enjoy the river as they once did.

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Benton CD Leads Control Effort

Benton Conservation District (BCD) is leading the community effort to deal with water stargrass. With funding and support from the Yakima Basin Fish and Wildlife Recovery Board and the National Fish and Wildlife Foundation, we’re educating and organizing landowners and volunteers.

In cooperation with the Washington Department of Fish & Wildlife, BCD located some traditional fall chinook salmon spawning grounds with safe and secure access. We recruited and organized volunteer work parties with the aid of regional media. Through the summer, BCD staff and volunteers cleared 1.5 acres of the riverbed, opening it up to salmon spawning again. Special thanks to the dedicated landowner and volunteers who shared their time this summer to make the Yakima River a better place for salmon and for people!

New tool unveiled to battle
water stargrass on Lower Yakima River
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