SACRAMENTO – The Department of Water Resources (DWR) said today boaters, anglers and residents downstream from Lake Davis in the Feather River watershed should be prepared for increased water flows and higher stream levels due to overflows from the Grizzly Valley Dam’s spillway. Water began flowing into the spillway March 21 for the first time in nearly 21 years.
The Grizzly Valley Dam spillway releases water from Lake Davis into Big Grizzly Creek and then to the Middle Fork Feather River. While DWR does not anticipate problems downstream of the reservoir near Portola, flows below the lake could exceed what residents, businesses and anglers have experienced over the past three decades. DWR in recent years has maintained lower Big Grizzly Creek flows between 10 and 200 cubic feet per second (cfs), but with the uncontrolled flows over the dam’s spillway, flows could increase substantially. Until this week, the reservoir had not reached its full elevation and capacity since May 20, 1996, when less than half an inch of water rose above the spillway.
DWR lowered Lake Davis in the 1990s to prevent storms from spilling invasive northern pike into downstream waterways. Out of an abundance of caution to protect native fish species, DWR has kept the reservoir level well below the dam’s rim. The California Department of Fish and Wildlife has seen no indication of northern pike inhabiting the lake since eradication efforts took place in 2007. In December 2016, DWR notified water users that it intended to resume normal operations at the lake and allow the reservoir to fill.
Rainfall this winter in northern California has been approximately twice the historical average.
Lake Davis is part of DWR’s Upper Feather River Project within Plumas National Forest. In addition to water supply, the 84,000 acre-foot reservoir provides recreational camping, fishing, picnicking and boating. The reservoir is created by Grizzly Valley Dam on Big Grizzly Creek, a tributary of the Middle Fork Feather River.