Focus on the Future

Diversifying Our Water Supply Portfolio to Adapt to the Continuing Effects of Climate Change and More Frequent and Severe Droughts 

As hydrologic conditions change in California, infrastructure that was built for more moderate conditions becomes less effective at conveying water where and when it’s needed most. Over the last decade, an increasingly wild swing between wet and dry years, often dubbed “weather whiplash,” has revealed vulnerabilities in current water supply sources. 

For example, when the SWP first began delivering water in the 1960s, it was mostly able to meet its delivery goals. However, over the last two decades, average deliveries have dropped to only 50-60% of contracted amounts and, in some years, those deliveries have been as low as 5%. 

Several factors have contributed to the SWP’s declining reliability, including:

• Stronger environmental regulations in the Sacramento-San Joaquin Delta that introduced new pumping restrictions and limited how much and when water can be exported.
• More frequent droughts, declining snowpack, and shifts in the timing of runoff into water supply reservoirs due to climate change, all of which have reduced water availability.
• Warmer winters that result in more precipitation falling as rain rather than snow and snowpack that melts earlier, causing pulses of runoff that do not always align with when water is needed or when it can be stored.
• Aging infrastructure, California Aqueduct capacity constraints caused by subsidence, and a Delta levee system that is vulnerable to earthquakes, sea level rise, and storm surges, which raise additional concerns about long-term delivery reliability. 

The SWP currently provides almost all of Calleguas’s water supply, and in 2022 it delivered such a small amount of water that Metropolitan enacted an Emergency Water Conservation Plan for Calleguas and five other Metropolitan member agencies that primarily receive water from the SWP. As a result, all of Calleguas’s retail water providers that served imported water during that time had to require their customers to limit outdoor watering to one day per week to conserve the limited supply available. Although the mandatory water restrictions were lifted less than a year later following intense winter storms, Calleguas’s Board of Directors determined that the District needed to diversify its water sources. While imported water will always be essential to Ventura County, the Board recognized that building a resilient water future for the region must include a more diverse portfolio of supply, storage, conveyance, and programs.

The Calleguas Board of Directors adopted the “New Model for Resilience” Strategic Plan in 2023. Since then, the District has engaged in a series of collaborative, iterative, and productive conversations with local and regional partners to envision and plan for long-term water reliability and resilience. This process, the Water Resources Implementation Strategy (WRIST), has built on the history of extensive regional collaboration to enhance existing partnerships and forge new ones. The goal of WRIST was to develop preferred portfolios of projects with a regional focus and evaluate them according to multiple criteria and priorities. With those portfolios identified, Calleguas is now embarking on the early stages of planning for implementation of the selected conceptual projects and programs to diversify and strengthen its water supply. Potential future investments under consideration include:

• Developing new local water supplies, such as making use of brackish (slightly salty) groundwater by constructing new desalter facilities
• Extending Calleguas’s water delivery system to allow locally produced water to be conveyed to all parts of the service area
• Groundwater storage programs to store water from wet periods so it is available during dry ones
• Maximizing the use of recycled water through advanced treatment and groundwater injection and extraction, as well as expanding existing recycled water (“purple pipe”) systems
• Interconnections with other water districts 

Weather whiplash also underscores the need to enhance the ability to capture and store water during times of abundant precipitation for use during the longer and more frequent droughts that will occur. Calleguas supports projects, such as the Delta Conveyance Project (DCP) and Sites Reservoir, to maximize the State’s ability to capture and store water when it is available for when it is needed most.