Happy New Water Year: The Blessing of Full Reservoirs for 2024

Wednesday, Oct 11th, 2023

By David Guy

As we move into October and the new water year in California, we are thrilled to be starting the water year with robust surface supplies as our reservoirs are generally at their maximum levels. The Central Valley Project (CVP) begins the 2024 water year with total reservoir storage of 8.17 million acre-feet, more than double of last year. See CVP. This past winter’s storms provided a huge boost to the State Water Project (SWP), as Lake Oroville levels recovered and had the single biggest increase in the SWP’s history last year. The SWP was able to capture a total of 3.5 million acre-feet in reservoirs since December 1, 2022. Oroville is currently at 136 percent of historical average today, up from 64 percent of average a year ago. See SWP. Other major reservoirs in the Sacramento Valley, such as New Bullards Bar, Camp Far West, and Indian Valley, are also starting the water year at maximum levels that allow for flood control operations while storing as much water as possible for the future. You can find reservoir levels at California Water Watch.

A new Public Policy Institute video on Drought and Floods highlights this dynamic as we wrestle with weather whiplash. I also recently joined My Ag Life (starts at 9:30) for a podcast that discusses this issue.

DWR and Reclamation are closely coordinating to ensure the state’s reservoirs have flood space available under a second year of flood conditions, as well as store as much water as possible in case of a return to drought conditions. San Luis Reservoir, the jointly operated reservoir in Merced County, sits at 190 percent of historical average today, up from 67 percent this time last year.

While the robust surface supplies look very promising for this next water year, groundwater conditions throughout California are mixed and vary across both the state and the Sacramento Valley. Water resources managers and Groundwater Sustainability Agencies (GSAs) are watching groundwater levels and quality to see how the aquifer systems have recovered on the heels of some very dry years where there has been little surface water available in certain parts of the Valley. One indicator of trends in the aquifer systems is seen by the groundwater level conditions that have been monitored and reported on the Department of Water Resources (DWR) California’s Groundwater Live. There is a lot to learn from the various trends seen on this website that will help inform local water and land use management. The encouraging signs are that most of the aquifer systems have recovered with one wet year with full surface supplies and moderate temperatures in 2023.

This scenario to begin the water year with full surface reservoirs and mixed aquifer conditions points toward several opportunities as we plan for the 2024 water year. The nature of California–with the maldistribution of water in time and place–coupled with seemingly more extreme weather events, offers new opportunities to advance a more modern water management system that better adapts to a changing climate and our state’s important values. This includes:

  • Advanced forecasting tools. California’s investments in forecasting and emergency preparedness paid off during last season’s storm events and the state is incorporating lessons learned during the last water year and advancing the science and technology that will be critical to managing water in the coming years. DWR and Reclamation will utilize the most advanced forecasting tools working with local water agencies and other partners like NOAA, Scripps, and others to prepare for the year ahead.
  • Full surface water deliveries. This water year should allow for full surface water deliveries, which are important for cities and rural communities, farms, wildlife refuges and floodplain reactivation for fish and birds. We have increasingly learned the value of water on the landscape for farms, fish and wildlife and groundwater recharge as we both explore and implement the reactivation of our historic floodplains, watershed management with a focus on forest health, and healthy farms and soils. Full water deliveries will serve these important purposes, it will help with further aquifer recovery and it will avoid the dramatic impacts we saw in 2022. See the Unprecedented Dry Period from 2020-2022.
  • Facilitating groundwater recharge. The Sacramento Valley has a strong interest in accelerating the pace and scale of multi-benefit groundwater recharge projects and want to partner more deeply with state agencies to achieve this goal. There have been important strides this past year in the policy arena to help facilitate groundwater recharge (i.e., executive orders, SB 122, and SB 659); yet, a more concerted effort is needed for local agencies to maximize the opportunities to recharge groundwater during these types of years to support our aquifer systems.
  • Advancing Sites Reservoir. Sites Reservoir is an environmentally beneficial, off-river reservoir that will capture excess water from major storms and save it for drier periods, helping California’s farms, businesses, cities, and refuges continue to supply reliable water when other sources are low. When operated in coordination with other Northern California reservoirs such as Shasta, Oroville, and Folsom, which function as the backbone to both the Central Valley Project and the State Water Project, Sites Reservoir will greatly increase flexibility, reliability, and resiliency of statewide water supplies to better prepare for our next dry year.

We live in a special place where our water management must evolve in tandem and in sync with both the needs of California and our climate. As we look to the future, our current population of 40 million will grow to 50 million by 2050; we are blessed with the most abundant agricultural bounty in the world; we are surrounded by a stunning landscape and related natural infrastructure; California is the 5th largest economy in the world; and people pursue endless recreational opportunities surrounding water in every part of the state. Water is essential for all these special features that define California. A strategic approach that recognizes this scenario and embraces California’s unique values in water is needed for this great state to continue to protect and enhance our communities, economy, and environment.

We are also blessed in California to have many of the best water resources managers in the world. They devote their lives to understanding and continually learning about this dynamic, as we know that every water year is different and serving water for multiple benefits is hard work that calls upon the expertise of every discipline surrounding water. We should all take the time to thank the water resources managers operating our complex systems as they toggle between wet and dry years and manage through the various tradeoffs that inevitably stare at each and every water management decision in California. As we enter the new water year and the policy discourse between wet and dry years, we should look at the issues through the lens of a water resources manager and focus on improving the various tools that water resources managers use and have available to manage our precious water supplies for multiple benefits. This will help our great state through both wet and dry years.

We would welcome further conversations and ideas to better manage water through different years at info@norcalwater.org.

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