Environment & Science

UC Davis maps farmland that can 'bank' groundwater during El Niño rains

For good groundwater banking, the secret is in the soil, according to UC Davis professor Helen Dahlke and UC Cooperative Extension specialist Toby O'Geen. A new web-based map helps pinpoint the most promising parcels.
For good groundwater banking, the secret is in the soil, according to UC Davis professor Helen Dahlke and UC Cooperative Extension specialist Toby O'Geen. A new web-based map helps pinpoint the most promising parcels.
Diane Nelson/UC Davis

In response to California's withering drought and a dwindling water supply, researchers at UC Davis have identified farmland that could potentially "bank" groundwater during what is predicted to be an unusually wet winter.

The team of researchers published their findings in the form of an interactive map that pinpoints exactly which pieces of farmland have the potential to absorb some of the heavy rainfall many climate scientists say could be brought on by this year's El Niño weather event.

The Soil Agricultural Groundwater Banking Index is based on research led by Toby O'Geen, UC Cooperative Extension specialist with the UC Davis Department of Land, Air and Water Resources.


(This map is part of the Soil Agricultural Groundwater Banking Index, which identifies farmlands with the most potential to capture groundwater and help recharge the aquifer. You can view the interactive map here. | Credit: California Agriculture journal)

O'Geen and his team surveyed millions of acres of farmland throughout California, identifying about 3.6 million acres of land where water can safely percolate deep into the soil without damaging crops or contaminating the water supply, according to a statement from UC Davis released Thursday.

"A lot of growers are interested in learning how they can help improve the groundwater situation in California," O'Geen said in the statement. "The index provides details on the groundwater-recharge potential for any parcel, which you can search for by address or access using your device's GPS."

Water tables in California have sunk by more than 100 feet as growers drill deeper wells, according to the university.

"Adding an extra few feet of water to even just 10 percent of California's cropland this winter could add an additional 3 million acre-feet of groundwater," said UC Davis Professor Helen Dahlke. "That could go a long way toward replenishing the 6 million acre-feet growers had to pump this year alone to cope with California’s drought."

Dahlke and a team of scientists plan to flood almond fields in the Central Valley in December, hoping to replenish aquifers without harming crops or drinking water, according to the statement.

You can view the map here.