From the air, scientists map ‘fast paths’ for recharging California’s groundwater.
California has a long history of groundwater extraction and, as many have warned, its aquifers are not as pristine as they once were. As of 2012, the state was responsible for extracting approximately 18 billion gallons of groundwater per day, representing about 11 percent of all groundwater withdrawals in the United States. Many of these are for purposes of agriculture, and for the most part they are being performed sustainably, with a growing awareness of the impact of these practices on public health.
The state-mandated groundwater abstraction for agriculture has not only resulted in reduced amounts of water that can be naturally taken from the aquifers, but has also resulted in significant pollution as well.
According to the U.S. Geological Survey, agricultural groundwater abstraction in California during the 20th century has resulted in significant and often-unanticipated impacts to the ecosystem on the land. On average, more than a third of the water is abstracted in California, and approximately 30 percent of that abstraction is for agriculture.
In the San Joaquin Valley, where much of the water abstraction occurs, researchers found that soil is being depleted and eroded by overgrazing. Scientists have noted that without this ongoing erosion and depletion, the soils in the region — primarily the sandy loam soils in the valley floor and the volcanic tuff underlying the hills — would eventually become too poor to sustain animal life and, eventually, will become unnavigable.
This is another issue of concern in the region, with a number of proposed pipeline projects planned for the San Joaquin Valley.
“California is poised to become a water-intensive, high population state, one with a growing water deficit,” says John P. Van Vlack, a hydrologist with the U.S. Geological Survey. “The continued growth of California’s population will require an increasingly larger amount of water and a larger and more intensive use of groundwater,” he says. “We are likely to experience increasing demands on our groundwater, and a more extensive utilization of surface water for irrigation.”
For this reason, in addition to the environmental impacts, state water officials are concerned about how much water is being extracted from the aquifers that run through some of the San Joaquin Valley’s most economically important agricultural areas, such as the San Joaquin Valley, Stanislaus National Forest and the Sierra
