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Fish Passage Improvement Program (FPIP)

Lake Davis - Big Grizzly Creek

photo of structure at lake davis outlet


Lake Davis is located in Plumas County on Big Grizzly Creek, which flows into the Middle Fork of the Feather River, then into the Sacramento River. The non-native Northern Pike (Esox lucius) was first observed in Lake Davis in 1994. Pike, a voracious predator and invasive species, could pose a serious threat to anadromous fish and other native species if allowed to pass through the outlet pipes of Lake Davis into Big Grizzly Creek and ultimately enter the Sacramento and San Joaquin River systems.

The Fish Passage Improvement Program was involved in efforts to eradicate the Northern Pike from Lake Davis. Continue to the Department of Fish and Game website for more information on Lake Davis fisheries management.

In 1996, DWR installed "graters" on the Grizzly Dam outlet pipes, to prevent fish from moving downstream. The graters killed most fish that left the reservoir through the outlet pipes, but may have allowed juvenile fish, larvae, and eggs to escape.


The purpose of the Northern Pike Containment System Project was to augment the graters on the Grizzly Dam outlet pipes with a containment system that prevents the release of Northern Pike of any life stage from Lake Davis into Big Grizzly Creek. The project, which furthers the goals of the CALFED Ecosystem Restoration Program, was paid for by DWR's Division of Operations and Maintenance, the Department of Fish and Game, and the Fish Passage Improvement Program.

FPIP prepared the Notice of Determination (208 KB), Mitigated Negative Declaration, Addendum to the Mitigated Negative Declaration, and Initial Study (3.42 MB) , Addendum Number 2 to the Mitigated Negative Declaration (999 KB), and Monitoring Plan (225 KB) for the project. The Monitoring Report (775 KB) describes environmental monitoring that occurred before, during and after construction of the containment system.

In 2007, DWR completed the project by installing the Northern Pike Containment System: a structure capable of passing flows up to 200 cubic feet per second through eight mesh basket "strainers" with 1 millimeter openings. The openings are small enough to prevent passage of eggs and larvae, as well as juvenile and adult fish. It is anticipated that the containment system will be in place for approximately five years, or until it is certain that all pike have been eradicated from the lake. FPIP staff are continuing the mitigation and monitoring required by the streambed alteration agreement.

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