National Drought Mitigation Center


Letting lawns go brown can preserve water for others during drought

December 7, 2017

The Platte River channel above the confluence of Elkhorn and Platte rivers was completely dry on August 21, 2012, with minimal flows down-river from the confluence. The Platte River experienced record low flows in 2012 with many areas running completely dry. Fish kills were reported, including endangered pallid surgeon. Photo courtesy of Jonathan Schelmann, via the Drought Impact Reporter.

People may assume drought always causes conflict between urban residents and farmers over water supplies. But a new study of Nebraska’s Platte River Basin finds that cities can ease tensions during drought by reducing their consumption and allowing other users, such as agriculture, to take priority.

“The traditional view of urban and agricultural water users is two straws competing for water from the same glass, contributing to conflict,” said Sam Zipper, lead author on the paper published in Ecology and Society and postdoctoral fellow at the University of Victoria in British Columbia. “We showed that cities can actually be key sites of adaptive management because urban water use can be reduced rapidly through outdoor watering restrictions.”

“We found urban and agricultural water users in Nebraska actually viewed drought as a common enemy,” said Kelly Helm Smith, study co-author and communications specialist at the National Drought Mitigation Center, based at the University of Nebraska-Lincoln. “But the drought in 2012 was relatively short-lived and Lincoln residents really only had mandatory restrictions on lawn watering for a few weeks. Things might have been very different had the drought had gone on for multiple years.”

The interdisciplinary team of researchers, supported by the University of Maryland’s National Socio-Environmental Synthesis Center in Annapolis, studied water use in the Platte River Basin in Nebraska, which includes the city of Lincoln, as an example of how different sectors respond during times of water stress. The group included experts in ecohydrology, resource management and policy, geography, and landscape ecology. They drew on that mix of backgrounds to analyze a novel combination of data including drought intensity, urban water use, farmer crop choices, well installations, and media coverage to get a sense of how different users reacted to the drought.

They found that farmers in Nebraska are highly dependent on irrigation as a source of water for their crops, particularly in the drier western portion of the state. In response to drought, they were more likely to rely on irrigation infrastructure, and even install more of it, to ensure crops were getting sufficient water. “Irrigation well installations are highest during and immediately following drought, and the share of water-intensive crops being planted in the watershed is increasing,” Zipper said.

During drought in 2012, which affected the whole state, Lincoln residents generally complied with the city’s voluntary and then mandatory restrictions on outdoor water use. The city subsequently added a well to its wellfield under the Platte River and has introduced the idea of pulling water from the Missouri River.

The team used media reports logged in the drought center’s Drought Impact Reporter to create a preliminary historic account of drought impacts and responses, and augmented what was in the media stories with other publicly available reports, plans and information. The researchers found evidence that Nebraska’s water governance institutions were able to learn from a 2002 drought, with a law that requires the conjunctive management of surface water and groundwater.

Water experts have long advocated conjunctive management of surface and ground water as a strategy for sustainable water use, and Nebraska has recently implemented it. With its strong agricultural heritage, recurring drought incidents over the past few decades, and the recent legislation to conjunctively manage groundwater and surface water resources, the researchers hope that the lessons learned in the Platte River Basin will be useful in other locations dealing with similar water issues.

 “As a whole, we demonstrate that urban water use may represent a flexible use of water that can be more rapidly and effectively curtailed during drought conditions when compared to agricultural users,” Zipper said. “We also conclude that although the existing governance mechanisms appear to protect water supplies, there is a concerning trend of increasing reliance on agricultural irrigation, which may create vulnerability to longer or more severe droughts of the future.”