By Terry Knight -- Lake County Record-Bee outdoors columnist
Updated: 05/05/2009 10:50:46 PM PDT
May is the month when Yolo County can legally start drawing water from Clear Lake. This year, because of the drought, Yolo County will only be allowed to draw approximately 21,000 acre feet from the lake. An acre foot is the amount of water it takes to flood one acre at a depth of one foot. It equals 325,851 gallons.
Yolo County is allowed to draw water from Clear Lake under the "Solano Decree," which states if the lake level is at 3.22 feet or greater on the Rumsey Gauge as of May 1, then a certain amount of water can be taken. If the lake level is less than 3.22 feet, then Yolo County gets no water.
As of May 1, the lake level stood at just above 4 feet on the Rumsey Gauge. Yolo County can take 21,593 acre feet of that amount. Compare that with 150,000 acre feet when the lake is considered full (7.56 Rumsey).
Many people are wondering how much the lake level will drop after Yolo County is finished taking its allotment of water. The surface area of Clear Lake is 43,790 acres when full and it contains 1,155,000 acre feet of water. At zero on the Rumsey Gauge, the surface area is 39,170 acres and the lake holds 842,000 acre-feet of water.
Presently the lake's surface area is about 41,000 surface acres. That means that the lake level will drop less than a foot after Yolo County is done taking out water. But there is also the evaporation factor. Because of the hot summers in Lake County, the lake level drops approximately three feet due to evaporation alone. In addition, there is a considerable amount of water taken from the lake by local water companies, lakeside residents and other uses. Add that all up and it comes out to the lake level being close to zero on the Rumsey Gauge by Oct. 1.
Low lake levels could impact the fishing and boating industry. At zero Rumsey many of the ramps around the lake will be unusable and many of the docks of the lakeside residents could be left high and dry. The bass and other game fish would probably relocate to the deeper water in the south end of the lake. A low lake level also would mean clearer water and a whole lot more aquatic weeds. When the water is clear, sun can penetrate to the bottom and spur weed growth.In fact, many people are already predicting that this summer will see massive weed beds for more than a mile offshore.
If Yolo County starts to draw water within the next few weeks it could have an impact on the spawning fish. The spawning beds would be more exposed in the shallow water and the young fry would be susceptible to predation from birds and other fish.
There also would be fewer areas to fish and the fishing pressure would increase dramatically. In fact, that's already happening. Lately the parking lots at the boat ramps have been full even on weekdays and it will only get worse as we head into the summer months.
It's not just Clear Lake that will be drawn down. The lake level at Indian Valley Reservoir is more than 100 feet down from full. Yolo County owns all the water in the lake and can draw out all it needs. By the end of the summer the lake level of Indian Valley Reservoir will be at one of the low points in its history.
A drought of only one or two years can be tolerated but the big fear is a continuing drought that could last several years. If that happens it could have a major impact on the local community.