You really have to hand it to Arizona: Even as its population has doubled and it has suffered through a decades long megadrought, the state uses less water today than it did 40 years ago.
Most Californians are feeling the effects of the drought. But in areas of the state where people rely on groundwater, such as the San Joaquin Valley, the pain of this drought is especially severe. Wells are going dry and there’s intense competition to find and pull more water from underground.
Scientists have produced a new method that holds the promise of improving groundwater management – critical to both life and agriculture in dry regions. The method sorts out how much underground water loss comes from aquifers confined in clay, which can be drained so dry that they will not recover, and how much comes from soil that’s not confined in an aquifer, which can be replenished by a few years of normal rains.
The research team studied California’s Tulare Basin, part of the Central Valley. The team found that the key to distinguishing between these underground sources of water relates to patterns of sinking and rising ground levels in this heavily irrigated agricultural region.
Groundwater is one of the world’s most important natural resources, but groundwater management has traditionally been governed by lax and uneven legal regimes which tend to focus on the extraction of groundwater or groundwater quality, rather than groundwater recharge.
In a January 2022 webinar from Berkeley’s Center for Law, Energy, and the Environment, Dave Owen, professor at UC Hastings School of Law in San Francisco, discusses the many human activities that can affect groundwater recharge, the existing legal doctrines that affect groundwater recharge, occasionally by design but usually inadvertently; and how more intentional and effective systems of groundwater-recharge law can be constructed.
From the Murray-Darling system to Great Artesian Basin, “invisible” underground groundwater is often the only water supply available across the vast majority of Australia—and its annual contribution to GDP is estimated at more than $6.8 billion a year.
However, overuse of groundwater during droughts and aquifer depletion has led to water crises, including in Australia’s “food bowl” the Murray-Darling Basin (MDB), California and Cape Town in South Africa, with more likely to follow as groundwater management is largely reactive and unlikely to avert more crises as climate change and population pressures grow.
A new era of groundwater management in California continues to take shape as local agencies develop and implement plans that identify how they intend to achieve groundwater sustainability goals over the next 20 years.
“The Sustainable Groundwater Management Act, if you haven’t heard about it, it’s knocking on your door and will soon be pretty much a part of your life if you’re trying to farm,” said Cordie Qualle, professional engineer and faculty fellow at California State University, Fresno.
The Sustainable Groundwater Management Act (SGMA) made the County of Madera responsible for groundwater management for the more than 200,000 acres that are not part of an irrigation or water district (the “white areas”) in Madera County. Like many regions in the Central Valley, Madera County is heavily groundwater dependent. The average annual shortage in the Madera subbasin alone is approximately 165,000 acre-feet per year, a number calculated over a 50-year period to account for both wet and dry periods.
With the Colorado River’s largest reservoir just 38% full and declining toward the threshold of a first-ever shortage, Arizona water officials convened an online meeting this week to outline how the state will deal with water cutbacks, saying the reductions will be “painful” but plans are in place to lessen the blow for affected farmers next year.
Lake Mead’s decline is expected to trigger substantial reductions in water deliveries in 2022 for Arizona, Nevada and Mexico. The largest of those cuts will affect Arizona, slashing its Colorado River supplies by 512,000 acre-feet, about a fifth of its total entitlement.
Last month, many regions passed a major milestone in implementation of state legislation that has the potential to transform the way crops are farmed in the state.
At the end of January, big regions of the San Joaquin Valley had to turn in their plans for how residents and growers would comply with the Sustainable Groundwater Management Act.
The Water News Network is San Diego County’s source for water news and information.
