The Three Decrees
Water management decisions for Clear Lake are guided by a series of court decrees that stipulate how much water the District receives from the lake, when water may be released for beneficial purposes, and when water must be released for flood control. The court decrees seek to balance the desire to provide water for irrigation, maximize rainfall storage but prevent flooding, and to recognize and maintain lake-based recreation on Clear Lake. The three decrees are known as the Gopcevic, Bemmerly, and Solano Decrees.
Gopcevic Decree
The Gopcevic Decree, handed down in 1920, first outlined the conditions that the Yolo Water and Power Company (and subsequent owners, including the District) could release water from Clear Lake. The lawsuit was brought by the owner of land adjacent to the lake in the interest of maintaining high lake levels for recreation and to prevent excavation of the Grigsby Riffle to increase outflow for irrigation. In 1918, 10,000 acres of rice were planted in Yolo County to support the wartime food supply. But a series of dry years resulted in very low levels on Clear Lake. In order to get irrigation water out of the lake, the District’s predecessor installed seven pumps at the Grigsby Riffle and pumped water over it during the 1918 and 1919 irrigation seasons. The water company also excavated about 2.5 feet from the Grigsby Riffle before the lawsuit stopped that work.
The court decision established that no water could be released from Clear Lake when the lake level fell below zero feet Rumsey, and that a full lake was 7.56 feet Rumsey. The decree also prevented future excavation of the outlet channel below negative four feet Rumsey.
The Gopcevic Decree also established a filling schedule that determines the maximum lake elevation during the winter months before water must be released to help prevent flooding around the lake. It also limited the quantity of water that could be released each month for irrigation from May to September. This release schedule was deleted from the decree in 1981 when the Solano Decree was set forth to prevent conflicting water release provisions.
Bemmerly Decree
While the Gopcevic Decree was motivated to keep water high in Clear Lake during the summer recreation season, the Bemmerly Decree was a result of a lawsuit brought to keep too much water from being released from the lake during the rainy months. Winter storms in 1938 caused Clear Lake to rise to 10.25 feet Rumsey. Houses, roads, and the state highway were flooded and marooned, and hundreds of thousands of dollars in property damage resulted. To try and lower the level of the lake faster, the County of Lake petitioned and obtained an appropriation from the State to excavate the outlet channel capacity and alleviate flooding. This work was done in cooperation with the Clear Lake Water Company (one of the District’s predecessors). The channel excavation had been underway for two months when Mary and Agnes Bemmerly filed a lawsuit to stop the work.
The Bemmerlys owned property along Cache Creek in Yolo County, and their property had been significantly damaged in prior high-water events. They argued that if the capacity of the Clear Lake outlet was increased, higher flows in Cache Creek would result in even more damage in the future. The court ruled in favor of the Bemmerlys, and prevented enlarging the outlet channel to increase the outflow capacity.
Solano Decree
The Solano Decree came about after the construction of Indian Valley Dam when the County of Lake filed suit against the District. Lake County argued that the environmental impact report prepared for the Indian Valley Dam construction was insufficient because, in the view of Lake County, it failed account for coordinated management of Clear Lake and Indian Valley Reservoir in order to maintain higher lake levels for recreation on Clear Lake. The case was brought to Solano County because it was considered neutral territory where neither side would have an advantage over the other.
After much negotiation, the District and Lake County entered into an agreement in February of 1978. This agreement established the amount of water the District may withdraw between April and October of each year depending on the level of Clear Lake as of April 30. If the lake is at 3.22 feet Rumsey on April 30th, then the District may not withdraw any irrigation water, if the lake reaches 7.56 feet Rumsey, the District may release up to 150,000 acre-feet of water. In addition, the decree includes a procedure for calculating the monthly amount of water that the District can withdraw each month. In effect, the Solano Decree limits the amount of water that may be withdrawn each month in order to maintain higher lake levels throughout the summer months on Clear Lake.
The table below shows the amount of water that the District is entitled to release during the irrigation season based on the water level on Clear Lake.