The U.S. Army Corps of Engineers San Francisco District (USACE) is projected to begin a series of high-flow releases from Warm Springs Dam at Lake Sonoma starting mid-morning Wednesday, March 15, in response to reservoir levels and improving downstream conditions on the Russian River. An increase in releases at Coyote Valley Dam at Lake Mendocino is also expected to occur Wednesday afternoon or Thursday morning.
Recent storms have significantly increased reservoir levels well into the flood control pool at Lake Sonoma for the first time since 2019. These storms have also sustained levels at, or close to, flood stage in communities along the Russian River. The river is now forecast to appreciably recede below flood stage. The high-flow release on Wednesday is intended to restore conditions capable of accommodating additional rainfall this season. This is the first time in nearly four years that a high-flow release is required to manage rising lake levels. Decisions to withhold high-flow releases during recent rains, and the current plan to manage reservoir levels through an approved, temporary increase in storage capacity have been regularly coordinated with partners in Sonoma County to ensure the safety of downstream communities.
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Lake Mendocino
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Lake Sonoma
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Coyote Valley Dam
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Warm Springs Dam
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* Current level (in feet):
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750.98
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466.72
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* Water stored (acre-foot):
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91,597
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288,766
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* Storage capacity (acre-foot):
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116,500
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381,000
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Significant high-flow releases up to 4,000 cfs will be made at Warm Springs Dam. The release is being timed to allow downstream river levels to recede while still allowing for as much time as possible to evacuate water from the dam prior to the next storm. Releases are expected to increase to 300 cfs Wednesday morning and then by approximately 1,000 cfs per hour starting Wednesday afternoon or Thursday morning and will be timed to coincide with decreasing river stage at downstream locations. Lake levels, river levels, as well as weather forecasts are constantly monitored by USACE. These projected release conditions are subject to change based on updated forecasts.
For more information on timing, magnitude and duration of potential flood releases, please visit the California Data Exchange Center website at http://cdec.water.ca.gov/queryRes.html.