Last week, Governor Gavin Newsom issued an executive order aimed at capturing more precipitation from recent storms and storing it in the state’s groundwater basins.
The order allows agencies to more easily divert flood waters by temporarily lifting some restrictions around permits. However, it keeps certain protections, like those created to safeguard wildlife and habitats, as well as others that are meant to prevent storing water that’s been contaminated by pesticides and other pollutants.
The decision comes amid a particularly wet winter, which itself follows years of drought. Experts say this pattern of extended periods of dryness with the occasional intense wet year is likely to continue.
The Department of Water Resources’ March 1 snow survey found that many parts of the Sierra Nevada are seeing above-average snowpack, with some areas nearing record levels. Erik Ekdahl, deputy director of the State Water Resources Control Board’s Division of Water Rights, said California will likely see flood conditions “unlike anything we’ve seen in recent memory” in terms of the longevity and level of water flow.
“When we do have these peak flows, given our reliance on groundwater, we need to maximize our opportunities to recharge the basins which have been kind of over tapped,” he said.
According to the executive order, groundwater use accounts for 41% of the state’s water supply and can account for over half of it during a critically dry year. In the past, this reliance on groundwater, combined with low water supplies, has resulted in overdrafting groundwater in parts of the state.
Isaya Kisekka, associate professor of agricultural water management and irrigation engineering at UC Davis, said areas in California that don’t have access to surface water — called “white areas” — are especially vulnerable. He added that many of these areas are already considered critically overdrafted.
“For these areas to have access to these flood stage waters that recharge their aquifers, I think that would be really great news for them,” he said.
Kisekka said overdrafting happens when an area extracts more groundwater than is naturally recharged. When that happens, it causes a host of issues like water quality degradation and sinking land.
“So over time, we overdraft the aquifers, the levels go down and you start to have problems,” he said. “That’s what you see in the San Joaquin [Valley], especially, or the Central Valley in many places.”
Jule Rizzardo, assistant deputy director of the Division of Water Rights, said managing this “new climate reality” in California will require adaptation in order to prevent overdrafting in the future.
“There are areas that need so much groundwater recharge after being so dry that it takes more than one storm or five storms or ten storms,” she said. “It's going to take, in some places, a couple of good years of consistent recharge over time.”
In the future, Kisekka said it’s important that the state continue to take advantage of intense wet periods to help boost groundwater resources. He also said demand management, which refers to setting limits on groundwater use in order to ensure its sustainability, is also key. Overall, he said it’s these efforts and more that will help areas in need.
The order, issued on March 10, expires on June 1. Although storms will likely have subsided long before June, Rizzardo said the executive order will facilitate capturing water from snowmelt later in the spring.
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