A new underground mapping technology that reveals the best spots for storing surplus water in California’s Central Valley is providing a big boost to the state’s most groundwater-dependent communities.

The maps provided by the California Department of Water Resources for the first time pinpoint paleo valleys and similar prime underground storage zones traditionally found with some guesswork by drilling exploratory wells and other more time-consuming manual methods. The new maps are drawn from data on the composition of underlying rock and soil gathered by low-flying helicopters towing giant magnets.

The unique peeks below ground are saving water agencies’ resources and allowing them to accurately devise ways to capture water from extreme storms and soak or inject the surplus underground for use during the next drought.

“Understanding where you’re putting and taking water from really helps, versus trying to make multimillion-dollar decisions based on a thumb and which way the wind is blowing,” said Aaron Fukuda, general manager of the Tulare Irrigation District, an early adopter of the airborne electromagnetic or AEM technology in California.

Innovative efforts to accelerate restoration of headwater forests and to improve a river for the benefit of both farmers and fish. Hard-earned lessons for water agencies from a string of devastating California wildfires. Efforts to drought-proof a chronically water-short region of California. And a broad debate surrounding how best to address persistent challenges facing the Colorado River. 

These were among the issues Western Water explored in 2019, and are still worth taking a look at in case you missed them.

In 1983, a landmark California Supreme Court ruling extended the public trust doctrine to tributary creeks that feed Mono Lake, which is a navigable water body even though the creeks themselves were not. The ruling marked a dramatic shift in water law and forced Los Angeles to cut back its take of water from those creeks in the Eastern Sierra to preserve the lake.

Now, a state appellate court has for the first time extended that same public trust doctrine to groundwater that feeds a navigable river, in this case the Scott River flowing through a picturesque valley of farms and alfalfa in Siskiyou County in the northern reaches of California.

As California embarks on its unprecedented mission to harness groundwater pumping, the Arizona desert may provide one guide that local managers can look to as they seek to arrest years of overdraft.

Groundwater is stressed by a demand that often outpaces natural and artificial recharge. In California, awareness of groundwater’s importance resulted in the landmark Sustainable Groundwater Management Act in 2014 that aims to have the most severely depleted basins in a state of balance in about 20 years.

Against a backdrop of widespread subsidence caused by increased groundwater pumping in the San Joaquin Valley, the general manager of one large irrigation district detailed ways growers are teaming with the district to overcome the diminishing groundwater supplies in the heart of California’s bread basket.

Chris White, general manager of the Central California Irrigation District (CCID), talked about the use of groundwater recharge basins on farmland during wet years during a special Aug. 16 briefing sponsored by the California Department of Water Resources and the Water Education Foundation held at Fresno State.