Department of Water Resources announces water percentages for 2023 water year, anticipates fourth year of dry season for California
SACRAMENTO, CALIF. – Water allocations from the California Department of Water Resources show a small increase of available water after last year’s distributions hit a record low.
On Dec. 1, the Department of Water Resources (DWR) announced an initial State Water Project (SWP) allocation of 5% of water requested by water agencies for 2023. This is an increase from last year’s water year, which according to the DWR, was the lowest SWP allocation to be distributed on record. Last year’s initial allocation, which was announced on Dec. 1, 2021, started off at zero percent, with a limited amount of water that could be used for designation for any human health and safety needs that were unmet.
This year, the state is gearing up for the fourth year of a dry season and persisting drought conditions, according to DWR. As California prepares for the circumstances, DWR will also review any requests received for more water that may be necessary for health and safety. This includes allocating a minimum supply for things like water for residents, sanitation for the sewage systems and fire suppression for fighting fires.
“This early in California’s traditional wet season, water allocations are typically low due to uncertainty in hydrologic forecasting. But the degree to which hotter and drier conditions are reducing runoff into rivers, streams and reservoirs means we have to be prepared for all possible outcomes,” Karla Nemeth, DWR director, said.
SWP provides water to 29 public water agencies in the state, which have a set amount of water that they request on a year-to-year basis. This year, almost all agencies were able to receive the water supply they requested, aside from four agencies that request a higher percentage but still received the allocated 5%, according to a DWR notice to SWP contractors. The public water agencies, which include facilities like the Tulare Lake Basin Water Storage District in Corcoran and the Kern County Water Agency in Bakersfield, serve approximately 27 million residents across California.
According to DWR, the department will consider increasing the percentage of water if water storage levels in Lake Oroville begin to show improvement as the wet season progresses. Lake Oroville is SWP’s largest reservoir of water, located in Northern California, and conserves existing water supply for DWR in the event that dry conditions persist.
The 5% water allocation is met through the water flow provided from winter storms as they enter the Delta. It is also met through water stored in the San Luis Reservoir, located in the eastern slopes of Merced County. According to DWR, water managers will monitor how the wet season develops and determine whether further actions are going to be necessary later in the winter. In California, rain and snow is traditionally received by the end of January, so water managers will reassess water conditions throughout the winter and spring.
Beginning in February, these assessments will incorporate the data for snowpack, which is ground snow in the mountains that persists until the weather warms up, as well as forecasts from runoff. As a way to improve forecasts for spring runoff into reservoirs, DWR is broadening the deployment of more sophisticated technologies. For the second year in a row, DWR has utilized more advanced technology like aerial snow surveys, which can collect snow measurements further upslope of the Sierra Nevada mountain range.
Additionally, DWR is working closely with senior water rights holders for the downstream from Feather River, which has a main stem that begins in Lake Oroville. In times of a major drought, senior water rights are the last rights to be cut. According to DWP, the department is working closely with the holders to monitor conditions and assess water supply availability in the circumstance that the dry weather continues going forward.
Every year, DWR provides the SWP allocation by Dec. 1, and the allocations are based on available water storage, projected water supply and water demands. As snowpack and runoff information is assessed through the wet season, the allocations are updated every month after the initial distribution, with a final allocation that is typically determined in May or June.
According to DWR, the lowest SWP allocation to be initially distributed was on Dec. 1, 2021, when the allocation was at zero percent with a limited amount of water that could be used for designation for any human health and safety needs that were unmet. As the water year progressed, the allocation was raised to 15% following a good turnout of water in December, but it ultimately dwindled back down after a dry spell followed, according to DWR spokesperson Ryan Endean.
“Last year, we did see a very wet December, but that was followed by a historically dry January, February and March, and ultimately the final allocation was reduced to 5% of requested supplies,” Endean said.
Compared to the previous December, Lake Oroville ended the 2022 water year with a level at about 400,000 acre-feet higher than last water year. According to DWR, for this time of the year, Lake Oroville remains at just 55% of the dam’s average water storage.