Wells Dug Deeper as Groundwater Recedes

Groundwater levels are falling, and wells are drying up. Areas across the United States, including Santa Barbara County, are drilling deeper for fresh water than ever before, according to data from a recent UCSB study led by Assistant Professors Debra Perrone and Scott Jasechko. Although this solution provides temporary relief, it’s ultimately unsustainable, they wrote in a paper published by Nature Sustainability on July 22.

Drilling deeper only puts a Band-Aid on the problem — and quite an expensive one at that since the process requires more energy to implement and pump water to the surface. In addition, most regions have a “floor” (maximum drill depth) because the water becomes too salty or hard to extract farther down. As a result, rural and agricultural areas that heavily rely on groundwater are at risk: It may become too difficult for them to update their water systems or keep up with climbing costs, explained Perrone.

Jasechko said they “were surprised how widespread deeper drilling is.” After four years of data collection, they analyzed more than 12 million wells across the country and found that 79 percent showed a deepening trend between 1950 and 2015. This is the most comprehensive report to date and could support the pair’s previous research — on the proximity of fracking to water wells and on uncontaminated aquifers — suggesting the United States has less usable groundwater than many realize.

In Santa Barbara, groundwater plays an important supporting role in the county’s water supply, and it’s something community members should care about. During our most recent drought when surface water sources like Lake Cachuma, the State Water Project, and the Gibraltar Reservoir delivered less resource, “We relied quite heavily on groundwater for a couple of years. Groundwater use in water years 2015 and 2016 made up 20 percent to 25 percent of the water supplies used by the city,” wrote Dakota Corey, a City of Santa Barbara water supply analyst in an email.

The research is informing a larger discussion on this precious resource than before, and the state has begun to track groundwater extraction. Experts worldwide will convene in Spain this October to discuss the future of groundwater sustainability during a conference co-organized by Perrone.