Water Available for Aquifer Replenishment report released by Department of Water Resources

By on April 16, 2018

The Department of Water Resources (DWR) has released the final Water Available for Replenishment (WAFR) report, which shows that water available for aquifer recharge may be limited in many regions, except in years of high precipitation. The update analysis of the state’s water resources indicates that investment, innovation, and infrastructure will all be key to achieving the state’s goal of sustainable groundwater management.

The Sustainable Groundwater Management Act directs DWR to prepare the WAFR report to help newly formed local groundwater sustainability agencies develop sustainability plans for critically overdrafted basins by January 2020. California’s Governor Jerry Brown signed into law a three-bill legislative package, composed of AB 1739 by former Assemblyman Roger Dickinson (D-7th District-Sacramento), SB 1168 by former Senator Fran Pavley (D-27th District- Calabasas), and SB 1319 also by Senator Pavley, collectively known as the Sustainable Groundwater Management Act (SGMA) in September 2014.

The WAFR provides a visual depiction of supply and demand in each the state’s 10 regions, as well as a range of potential water available for replenishment estimates. The report also analyzes water supply, demand, and runoff in each region to estimate how much surface water could be available to replenish groundwater basins. Public comments submitted in response to the draft report published last year are incorporates in the final report.

“The WAFR report makes it abundantly clear that a diversified water resources portfolio is needed at the local, regional and state levels,” DWR Director Karla Nemeth said. “If California is to simultaneously bring sustainability to its groundwater basins, cope with climate change, and meet future demands, water managers must embrace a comprehensive, innovative approach.”

Approximately 1.5 million acre-feet (MAF) of water may be available to replenish groundwater basins in an average year according to DWR estimates. More water could be available for replenishment in the future years with additional investments in water management through conservation, conveyance improvements, desalination, recycling, stormwater capture and water storage.

Overdrafted water basins are the result of many issues primarily declining water deliveries and climate change. Water deliveries from the State Water Project and the federal Central Valley Project have reduced groundwater overdraft in many basins in the state; however, average deliveries have declined in recent years due to the state’s prolonged drought and regulatory requirements to protect water quality and critical species in the Sacramento-San Joaquin Delta and tributaries. Climate change is expected to further exacerbate these challenges.

The WAFR report indicates that constructing additional storage north and south of the Delta and improving the Delta’s conveyance infrastructure, such as proposed in the California WaterFix project, would minimize the decline of water project deliveries and provide a more reliable supply of surface water for replenishment and other purposes. Although the future implementation of WaterFix is still uncertain, the vote earlier this week by the Metropolitan Water District of Southern California Board of Directors to fund $10.8 billion of the project’s estimated cost of $16.7 billion for three new water intakes in the northern Sacramento-San Joaquin Delta and two tunnels to carry the water under the Delta may hasten the project’s future.