Title
Consider recommending a release schedule for Nacimiento and San Antonio reservoirs for 2026
Report
RECOMMENDATION:
Staff recommends that the Monterey County Water Resources Agency Water Resources Advisory Committee:
Recommend that the Monterey County Water Resources Agency Board of Directors Consider Adopting a Release Schedule for Nacimiento and San Antonio Reservoirs for 2026.
SUMMARY/DISCUSSION:
In most years, continuous reservoir releases are made during the “conservation season” (April-October) to optimize Salinas Valley groundwater recharge as well as Salinas River Diversion Facility (SRDF) operations. These conservation releases are guided by a schedule developed each year in late winter to early spring by staff to approximate the expected sequence of reservoir withdrawals that fully accounts for a complex set of obligations, constraints and, to the extent possible, hydrologic conditions.
Key obligations include annual withdrawal limits and conditions-based flow prescriptions supportive of federally listed species. Both are stipulated in the water rights that authorize the Agency to store, withdraw and re-divert waters of the state within the Nacimiento, San Antonio and Salinas River watersheds. Constraints are of physical, administrative and environmental nature. Physical constraints include elevation-dependent limits on methods and rates of releases as well as safe operating limits of release outlets; administrative constraints include guaranteed water allotments established by contractual agreements. Minimum required releases, required lagoon bypass flows, as well as limits on release rate changes are among the environmental constraints accounted for in the development of the annual release schedule.
The Agency has made releases during 13 of the 17 summer conservation seasons since the Salinas River Diversion Facility (SRDF) began operating in 2010. Two extended droughts resulted in insufficient reservoir levels to operate from 2014-2016 and in 2022. More recently, 2023-2025 marked a return to wet conditions providing large storage increases at both Reservoirs and enough water to fully operate in all years since 2023. Combined storage as of March 19, 2026 is sufficient to plan a fourth consecutive full SRDF diversion season this year.
The attached proposed 2026 release schedule accounts for current reservoir inflow rates but assumes no new inflow events for the remainder of the calendar year. The proposed schedule limits releases from Nacimiento Reservoir to below 280 cfs due to planned maintenance activities expected to be complete by July 1. Releases from Nacimiento Reservoir may exceed 280 cfs once maintenance activities are complete.
SRDF startup is expected to occur as early as the first week of April. The proposed schedule reflects an assumed April 1 start date and maintains conservation flows to recharge the Salinas Valley groundwater basin and operate the SRDF into mid-October while meeting the operational requirements of State Water Resources Control Board appropriative water rights held by the Agency for the Nacimiento and San Antonio Rivers.
As is the standard procedure each year, the release schedule will be updated monthly based on actual weather and river conditions, changing SRDF demands, and other reservoir operational considerations as may be necessary subsequent to the development of this draft release schedule.
OTHER AGENCY INVOLVEMENT:
None
FINANCING:
None
Prepared by: Joseph Klein, Water Resources Hydrologist (831) 755-4860
Attachments: Reservoir Release Schedule For 2026