LAKE COUNTY — Yolo County farmers are looking to the skies for rain in hopes that Clear Lake will fill or, at the least, the lake level will rise to above 3.2 feet on the Rumsey Gauge before May 1. Yolo County can”t draw any water from Clear Lake if the lake level is 3.22 feet or less on the Rumsey Gauge as of May 1. The lake level is currently at 3.07 feet and with no storms forecast, Yolo County is preparing for the worst.
According to Jennifer Reed, project manager for the Yolo County Flood Control and Water Conservation District, if Clear Lake”s level doesn”t rise to 3.22 feet or greater on the Rumsey Gauge, Yolo County receives no water from the lake. She said that farmers in Yolo County would have to rely on irrigation water from Indian Valley Reservoir or wells. According to Reed, the district has already informed farmers that they will be on a water allotment this year. She said that means the farmers will have to decide what crops they plan on planting and how they will conserve the available water. The primary crops in Yolo County are tomatoes, rice, almonds, walnuts, safflower and some cotton. The other bad news for the farmers is that any water that does not come from Clear Lake or Indian Valley Reservoir will be more expensive.
Clear Lake has failed to reach 3.22 feet on the Rumsey Gauge as of May 1 only eight times since 1873. The last time was during the drought of 1976-77.
The Solano Decree of 1978 (revised 1995), very specifically outlines the operation of Clear Lake for Yolo County irrigation purposes.
A comparison of water allocations show that when Clear Lake is at 3.5 feet on May 1, Yolo County receives only 7,847 acre-feet of water. An acre foot is 326,000 gallons. If the lake level is 4 feet as of May 1, Yolo County gets 21,593 acre-feet of water. At five feet it is 49,353 acre-feet and when the lake is full at 7.56 feet Yolo County gets its full allotment of 150,000 acre-feet of water.
The district can only draw water out of the lake up to Oct. 31 regardless if the lake is full or not. However, the lake level cannot be allowed to drop below 1.25 feet on the Rumsey Gauge as of Oct. 31. It should be noted evaporation takes about three feet each year. Local water users also take a considerable amount of water.
There are no similar restrictions on Indian Valley Reservoir with the exception that enough water has to remain in the lake to protect the fishery.
Reed said that as it now stands if Clear Lake doesn”t reach 3.22 feet on the Rumsey Gauge the district will be drawing much of its needed water from Indian Valley Reservoir. She said that even if the county receives several major storms it”s unlikely Clear Lake will reach anywhere near the full mark by May 1.
The level of Clear Lake is measured in reference to the “Rumsey Gage” which was established by Capt. DeWitt C. Rumsey at Lakeport in 1873. The actual gauge is located at the Vector Control Office in Lakeport. Zero Rumsey is considered the natural low water level of Clear Lake.
Zero Rumsey is determined as when water ceases to flow over a rock sill at the confluence of Cache and Seigler creeks, which is located near Lower Lake. A full lake, by definition, is reached when the lake measures 7.56 feet on the Rumsey Gage.
