Saturday, 13 April 2024

Rain helps raise Clear Lake's low level

LAKE COUNTY – December's rains are helping to replenish local creeks and a very low Clear Lake, but despite much-needed influxes of water the lake is still at a 15-year low.

On Sunday, a US Geological Survey water gage showed that Clear Lake was at 0.69 feet Rumsey, the measurement used specifically for Clear Lake. On Dec. 27, 2008, the lake was at 1.16 feet Rumsey.

November and December typically are the months of the year when the lake is at its lowest level, based on a survey of lake level records.

Clear Lake is considered full at 7.56 feet Rumsey, according to the Lake County Water Resources Division.

Water Resources explains on its Web site that the lake's natural level is maintained by a rock sill – the Grigsby Riffle – located at the confluence of Cache and Siegler creeks near Lower Lake. The lake's natural low water level is “Zero Rumsey,” a measurement equivalent to 1318.26 feet above sea level.

Rains over the past two weekends have raised Clear Lake a small amount overall. While the lake is low, it was at its lowest point for the year on Nov. 20, when it was at 0.45 feet Rumsey, according to US Geological Survey records.

The last time it was as low, or lower, than that Nov. 20 measurement was in November of 1994, when records show it was down to 0.39 feet Rumsey.

US Geological Survey stream gages around the county also showed creek levels picking up over the past two weekends.

The lowest level recorded for the lake over the past century was -3.50 feet Rumsey, recorded in late September of 1920, according to Water Resources. The lake's maximum gage height, 11.34, was recorded on Feb. 21, 1986.

Yolo County Flood Control & Water Conservation District, which owns the water rights to Clear Lake as well as to Indian Valley Reservoir, reported that the reservoir was at 12,834 acre feet on Dec. 22, down by more than 6,300 acre feet from December 2008.

E-mail Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it. . Follow Lake County News on Twitter at and on Facebook at .

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