New Report Released on Delta Drought Response Pilot Program

July 29, 2024
WEST SACRAMENTO – The Delta Conservancy has released a final report on outcomes of the 2023 Delta Drought Response Pilot Program, an experimental program that was launched in order to test drought-resistant field management practices in the Sacramento-San Joaquin Delta Watershed.

Delta growers participating in the program received financial incentives to carry out a variety of water conservation practices as well as beneficial bird habitat practices on their fields. Specific practices included shifting crops, reducing irrigation, delaying harvest to protect nesting cover for birds, and intentional flooding of croplands for bird habitat. A total of 61 projects, encompassing 18,450 acres, were successfully enrolled in 2023.

Some key takeaways from the report include:

• Reducing applied irrigation amounts through deficit irrigation of crops, changing crop type, and even fallowing or idling cropland may not be sufficient to produce substantial water savings on farm fields within the legal Delta, especially on low elevation fields.
• Agricultural areas at lower elevations resulted in water savings less consistently, and areas at higher elevations show more potential for water savings and lower cost/acre-foot of water saved.
• In addition to field elevation, variation in estimated water savings may also have been driven by crop type, vegetation management, soil type, local flooding, and overall water year conditions.
• Estimated average water use was slightly higher in the 2023 water year than in the 2022 water year, likely due to higher soil moisture.

The report evaluates and analyzes whether changing specific field management practices could result in water savings, protect Delta water quality, mitigate potential drought impacts on fish and migratory birds, and promote soil health. The 2023 report focuses on the results from the 2023 water year (October 1, 2022, through September 30, 2023) with a short analysis comparing fields enrolled in both the 2022 and 2023 programs.

The Department of Water Resources provided $10.8 million to fund the 2023 program, which was administered by the Delta Conservancy through an interagency agreement. The 2023 program was developed and overseen through a partnership with DWR, the Delta Conservancy, the Office of the Delta Watermaster, The Nature Conservancy, the California Department of Food and Agriculture, UC Merced, the UC Cooperative Extension, and conducted in coordination with Delta water users.

“It was an honor to be able to support this program and have the opportunity to partner with so many Delta farmers to better understand how we can manage through drought conditions,” said Delta Conservancy Executive Officer Campbell Ingram.

The program’s Oversight Committee performed analyses using OpenET, a non-invasive and open-source satellite-based method, to evaluate consumptive water use and estimate water savings. Additionally, as part of a multi-year study, a UC Davis research team is using micrometeorological stations to continue collecting data at six sites that were enrolled in the program. The collected measurements will help inform remote sensing technologies and improve future responses to drought.

“The Delta Drought Response Pilot Program advances our understanding about water conservation across the Delta. The Office of the Delta Watermaster is greatly appreciative of the Department of Water Resources for funding this study, and we thank all partners for their collaborative efforts with other State Agencies, Delta water users, research partners, and other contributors,” said Delta Watermaster Jay Ziegler. “Our office is committed to further advancing our shared understanding of consumptive use of water in the Delta through the work of the Delta Measurement Experimental Consortium, along with other partnerships.”

The full report is available on the Delta Conservancy’s Delta Drought Response Pilot Program webpage.

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