These strategies conceal a more fundamental problem: the unchecked growth of water consumption. The Southwest is in an “anthropogenic drought” created by the combination of natural water variability, climate change and human activities that continuously widen the water supply-demand gap.
In the long run, this can lead to “water bankruptcy,” meaning water demand invariably exceeds the supply. Trying to manage this by cranking up water supply is destined to fail.
More than 7,000 miles away, Iran is grappling with water problems that are similar to the U.S. Southwest’s but more severe. One of the driest years in the past five decades, on the back of several decades of mismanaged water resources, brought warnings of water conflicts between Iranian provinces this year.
Asenvironmentalengineers and scientists – one of us is also a former deputy head of Iran’s Department of Environment – we’ve closely studied the water challenges in both drought-prone regions. We believe past mistakes in the U.S. and Iran offer important lessons for future plans in the U.S. Southwest and other regions increasingly experiencing drought and water shortages.
Groundwater pumping: A temporary fix with consequences
Iran offers a case study in what can go wrong with that approach, as our research shows. The country nearly doubled its groundwater extraction points between 2002 and 2015 in an attempt to support a growing agricultural industry, which drained aquifers to depletion. As its water tables drastically declined, the groundwater’s salinity increased in aquifers to levels that may no longer be readily suitable for agriculture.
In Iran, multiple interbasin water transfer projects doubled the flow of the Zayandeh Rud, a river in the arid central part of the country. The inflow of water supported unsustainable growth, creating demand without enough water to support it. In dry years now, no one has enough water. Many people in Khuzestan – the region supplying water to central Iran – lost their livelihood as their farms dried out, wetlands vanished, and livestock died of thirst. People in central Iran also lost crops to the drought as incoming water was cut. Both regions saw protests turn violent this year.
Another project, the California Aqueduct, was constructed in the 1960s to transfer water from the Sacramento-San Joaquin Delta in Northern California to the Central Valley and southern parts of the state to support agriculture and some urban demand. This also did not close the water demand-supply gap, and it pushed economically and culturally important native fish species and ecological systems in the delta to the point of collapse.
Looking ahead in light of looming water bankruptcy
As the continued influx of population into the U.S. Southwest raises water demand in the face of shrinking water supply, we have to wonder whether the Southwest is heading toward water bankruptcy.
While there is no easy solution, a number of actions are possible.
First, recognize that water shortages cannot be mitigated only by increasing water supply – it’s also important to manage water demand.
Cities can save water by curbing outdoor water losses and excess water use, such as on ornamental lawns. Californians successfully reduced their water demand by more than 20% between 2015 and 2017 in response to severe drought conditions. Replanting urban landscapes with native drought-tolerant vegetation can help conserve water.
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There are also emerging technological solutions that could boost water resources in some regions, including fog water collection, which uses sheets of mesh to capture moisture from fog, and desalination plants that turn seawater and saline groundwater into drinking water. One new desalination plant planned for Huntington Beach, California, is awaiting final approval. Environmental consequences of these measures, however, should be carefully considered.