The initial forecast could change if the state receives more rain and snow.
By Alex Riquelmy, Courthouse News Service
The California Department of Water Resources on Friday said its initial State Water Project allocation forecast is 10% of requested supplies for next year — a 5% increase from its December 2022 initial forecast.
The department, which issues its initial forecast by Dec. 1 each year, pointed to current levels of reservoir storage, as well as the expectation of extremely dry conditions, as the reason for its forecast level. Dry soil, runoff and storage in Lake Oroville also play a role.
So far, the water year — which starts Oct. 1 — has yielded little rain. The few storms that have swept into the state did not significant rain or snow.
The allocation forecast could change, depending on if the state receives more rain and snow. Allocations get updated each month after snowpack, rainfall and runoff are examined. A final allocation occurs in May or June.
Friday’s forecast is a view into 2024. It applies only to water deliveries in that year and has no effect on existing water supplies or water captured this year.
The State Water Project is a storage and delivery system spread over 700 miles that’s composed of canals, reservoirs and hydroelectric systems. It provides water to 29 public water agencies, which in turn serve some 27 million Californians.
“California’s water year is off to a relatively dry start. While we are hopeful that this El Niño pattern will generate wet weather, this early in the season we have to plan with drier conditions in mind,” department director Karla Nemeth said in a statement. “California’s water supply continues to benefit from our aggressive efforts last season to capture record rain and snow melt in our reservoirs and groundwater basins.”
El Niño conditions mean there’s a greater chance of storms. However, nothing is certain about the weather. Seven El Niño events have occurred so far this century. Two of them trended wet and two dry. The other three brought average rainfall.
Despite the slow start to rainy weather, there are positive signs. Most reservoirs in the state are above average. Out of the state’s 17 major reservoirs, only three were beneath their historical averages as of late Thursday. Lake Oroville, the largest, was at 133% of average. San Luis Reservoir was at 109% of average.
The State Water Project last winter captured 3.5 million acre-feet of water in its reservoirs. It delivered 2.7 million acre-feet in allocated water, along with another 400,000 acre-feet to its contractors this year.
The department, working with the Metropolitan Water District in Southern California, filled Diamond Valley Reservoir for the first time in three years.
Additionally, the state redirected excess storm water for groundwater charge. The department estimated that over 3.8 million acre-feet of water was used for recharge, which includes water that’s naturally occurring and permitted by government agencies.
Recharge is when water seeps into the earth, replenishing aquifers. It can be natural or intentional.
It’s typical for the department to issue an initial allocation forecast that’s low after wet years. For example, the 2018 water year saw a 15% initial allocation, which followed an 85% final allocation for the prior year. The 2020 water year began with an initial 10% allocation, despite a 75% final allocation for the year before.
Both 2017 and 2019 were wet years.
THIS JUST IN … DWR Announces Initial State Water Project Allocation of 10 Percent for 2024
