As we move into summer, the water year is shaping up in the Sacramento Valley. Although we are in a dry year as shown below, there is generally good surface water storage in reservoirs (see CDEC) and the region’s groundwater aquifers are generally in balance.
We are continually reminded that there is variability inherent in California’s precipitation and weather patterns, which has been particularly vivid this year, and our water system has been built to address this variability and the maldistribution of water in California. We are also reminded that there is tremendous value in having stored water, both in reservoirs and aquifers, for both flood protection earlier in the year and for water supply management for all beneficial uses in these types of years.
To summarize the water picture in the Sacramento Valley this year:
Term 91. The State Water Board on June 5 issued notices of curtailments under Term 91, which is designed to protect project releases from storage when the Delta is in balance. More information is available from the SWRCB.
Sacramento River. With respect to the Sacramento River, Reclamation on June 8 found “the forecasted inflow to Shasta Lake is currently projected at greater than 3.2 million acre-feet, and we are in a “Shasta Non-Critical” year. California Department of Water Resources’ Bulletin 120 was updated on June 4, showing a large increase in Shasta Lake inflow since the May 1 forecast. The forecasted inflow to Shasta Lake is currently greater than 3.2 million acre-feet, changing the previous determination of a “Shasta Critical” to “Shasta Non-Critical” water year as defined in certain Central Valley Project contracts.” Both Sacramento River Settlement Contracts and the National Wildlife Refuges will receive full supplies. Importantly, the Bureau of Reclamation, in consultation with its fishery partners, is working through a Sacramento River Temperature Plan and it will continue to work with water suppliers to adjust its operations this year to help manage temperature issues in the upper Sacramento River for incubating salmon, while also serving water for birds, cities and rural communities and farms.
CVP Water Supplies. For Central Valley Project contracts, the Municipal and Industrial (M&I) supplies on both the American and Sacramento Rivers will receive a 75% allocation; and the allocations for north of Delta Agricultural Water Service Contractors along the west-side of the Valley and in Shasta County are at 50%.
Water resources managers in Northern California have learned from recent wet and dry years and they are working hard to deliver water for multiple benefits throughout the region. Thanks to the good planning and work of water resources managers, Northern California is prepared for this water year. For a further discussion on the variability in the region, see Drought, Flood and Fire in the Sacramento Valley.