World Groundwater Day

As we celebrate World Water Day today, we’re looking at that unseen and unsung hero in the world of water: groundwater. In the U.S., over 50 percent of us rely on groundwater for drinking water, and in places such as California, groundwater becomes essential for drinking, farming, and more during a drought.

But because it’s underground, regulating the usage of this precious resource has been relatively non-existent. “California has been overpumping groundwater for decades, by millions of acre-feet per year,” according to Andrew Fisher of UC Santa Cruz. (One acre foot is equal to 325,851 gallons of water.) The good news is that in 2014, California passed the Sustainable Groundwater Management Act (SGMA) to manage groundwater—both its pumping and recharging. The act allows local governments to establish Groundwater Sustainability Agencies (GSAs) to implement this new state policy. Fisher and colleagues recently created a set of recommendations in how to set up and run these new GSAs.

The drought has made groundwater overdraft worse in many areas, leading to subsidence of the ground, collapse of aquifers, and (along the coast) seawater intrusion. “SGMA provides a once-in-a-lifetime opportunity to change how groundwater resources are managed and to put basins on a path towards water security,” Fisher says.

With the heavy rains this El Niño year, recharging these groundwater aquifers for future dry years is forefront for many scientists and water agencies. In fact, Fisher is collaborating with regional partners to identify locations and create projects along California’s Central Coast that will help recharge overstressed aquifers. “This region has been working for decades to meet requirements that are only now being imposed on other parts of the state,” he says. “We are not part of big surface water transfer systems, so we have to make do with what we have.” He currently has a system in place on a large ranch in the Watsonville area to capture stormwater into a pond and direct it to an underground aquifer. (For more information on his projects, check out this Scientific American article, or the team’s study on potential recharge sites.)

With urban and suburban development, capturing stormwater to replenish groundwater is increasingly challenging, but many agree that it needs to be a priority. A 2014 report by our friends at the Pacific Institute and NRDC details the potential of capturing this liquid treasure, with the potential to increase both groundwater and above-ground water supplies by 420,000 acre-feet per year!

We’re getting smarter about using and refilling our precious groundwater resources with the hopes it will be around for centuries to come. Happy World Groundwater Day!

If you want more groundwater information, click for more news about stormwater recharge, suggested priorities to reform California’s groundwater management, an in-depth look at groundwater resources around the world, and Science Today writer (and Stanford professor) Rob Jackson’s research into groundwater contamination.