(The Hill) – Underground storage could be key for western states to survive water shortages and extreme weather.

Underground aquifers have served as reliable sources of water for many years. During the wet season, aquifers naturally fill up, helping the area survive in dry years.

But rising demand for water, coupled with climate change, has created a shortage as states pump water out of aquifers faster than they can be replenished.

Fallout can also lead to corruption vegetation and wildlife As streams dry up and aqueducts and flood control structures are damaged, the sinking earth.

Local governments and researchers across the country are working on more efficient ways to replenish depleted aquifers.

By overpumping the aquifer, “we’ve created a space. There’s a subterranean space that was once filled with water,” says the director of the water program at the University of California, Berkeley School of Law’s Center for Law, Energy, and the Environment. As one Michael Kiparsky explains:

“And what we can do with these groundwater recharge projects is take advantage of that space, which is much larger than all the surface reservoirs that currently exist or could be built combined. ” he said.

California, Arizona, other states Managed aquifer recharge has been used for years to better regulate local water supplies.

Recharge projects, if implemented on a sufficient scale, have the potential to enhance water security in drought-affected regions while improving environmental health.

If that happens, Kipalski said, “it could create a whole new water supply that we didn’t know about before.”

Local initiatives

California — where 85 percent 80% of the population depends on groundwater for part of their supply, and more than 340 recharge projects have already been proposed.

California Department of Water Resources Announced this month Helps expedite and meet the permitting process for recharge projects its goal Increase average groundwater recharge by at least 500,000 acre feet annually.

of orange county The agency alone pumps 65 million gallons of treated water into Anaheim’s recharge ponds every day.County began recharging water through infiltration basins 1936 It serves as a model for other communities looking to implement managed aquifer recharge projects.

“If we want to maintain our ground water system, not deplete it or extract it, and have enough water for everything else: agriculture, cities, the environment, streams, we need a lot of water. needs to be injected into the ground,” said Andrew Fisher, professor of Earth and Planetary Sciences at the University of California, Santa Cruz. “If you don’t do that, you literally have no choice.”

Groundwater recharge projects can take many forms.

Communities may create infiltration basins where rainwater or excess river flow is collected in deliberately left open basins. Over time, water sinks into the soil below, eventually becoming an aquifer. Dry wells that stop above the water table and infiltrate the remainder can be constructed along with injection wells that direct water to the aquifer.

Arizona has a long history of managed aquifer recharge efforts. Arizona Water Bank Authority (AWBA). From the beginning, the authorities have used recharges to save nearly. 5.6 billion cubic meters The amount of surface water in the Colorado River as of 2019.

The early 2000s saw an increase in the number and capacity of recharge projects throughout Arizona. Researchers attribute the project’s success to local political consensus, favorable hydrogeology, public funding, and other factors.

“AWBA has a strong regulatory framework, combined with public institutions and funding, to [managed aquifer recharge] on a large scale and how [managed aquifer recharge] A wide range of water management and public policy objectives can be achieved. ” 2021 UNESCO Report Talked about practice.

The city of Tucson model example Thanks to our flexible approach to using renewable surface water supplies.

In 2018, the city stored and recovered 76 million cubic meters in the same year, and stored another 76 million cubic meters for long-term use.

Sharon B. Megdal, director of the Center for Water Resources Research at the University of Arizona, explained in an interview with Changing America that the city uses “soil as a method of treating surface water.”

Surface water seeps into aquifers and mixes with existing groundwater, allowing authorities to draw the mixed water and provide it to customers, she said.

Despite the established nature of Arizona’s program, groundwater is still being over-pumped in some areas and aquifer levels continue. decline.

“Arizona has a very extensive history of successfully using managed aquifer recharge, but there are still many opportunities,” Megdal said. “We don’t have all the answers. There is still much work to be done. I’ve done a lot of things successfully.”

When it comes to expanding the scope of recharge operations, “because of the impacts on water quality and other types of impacts, it is very important to have the right regulatory framework for both adequate protection and predictability.” It’s important,” Megdal said.

challenges remain

One type of groundwater recharge project is Flood-MAR, or the recharge of flood-controlled aquifers. As part of this process, water managers can divert water that accumulates in rivers during large-scale flows to other areas, flooding the land. during the winteror rainy season, and cultivate the land in summer.

“One of the challenges of flood recharge is finding land that is not already used for other uses, such as homes or fields. It’s a technical term for a place where it can flow quickly into a water layer,” explained Kiparsky. If the project is intended to capture flood waters, there may also be legal issues as downstream flow claims may already exist.

Additional challenges for recharge projects arise when water is collected in an urban environment. Cities may not be located on favorable geological conditions for water to infiltrate the aquifer. Urban groundwater can also be contaminated with oil droplets and car tire debris. This water can be treated before entering the aquifer, but treatment is expensive.

For other projects, the community will have to determine the best locations for charging to alleviate the need to build new transport infrastructure.

“In some cases, some of the stored water needs to remain in the aquifer and cannot be withdrawn later,” Megdal said. This is because the groundwater is moving and it may not be possible to retrieve all the water that the community put in before it moved.

Despite the many challenges inherent in collecting different types of water in different areas at different times and in different ways, “there are many opportunities to do so. [managed aquifer recharge] It depends on the water source you’re talking about, the end use you’re talking about,” Megdal said.

“People are recognizing that they must look to all water sources and opportunities to use them wisely,” added Megdal.

Not only will increased water storage help future water security, rising groundwater levels will reconnect streams, improving fish and vegetation conditions along stream corridors.

“There’s too much water when you don’t want it and not enough when you need it, so storage is key,” Kipalski said.

“The fact that we created this massive space underground is key to the problem,” added Kiparsky.