Supply of drinking water isn’t endless

Emily Berglund is an associate professor of civil, construction, and environmental engineering at N.C. State.
Emily Berglund is an associate professor of civil, construction, and environmental engineering at N.C. State. EMILY BERGLUND

Emily Berglund, is an associate professor of civil, construction, and environmental engineering at N.C. State, explains how we can make the most of one of our nation’s most prized natural resources, water. Questions and answers have been edited.

Q. How finite of a resource is water?

A. Cities need high volumes of water in the summer, when the climate tends to be drier, and without proper management, storage, and conservation, it is possible that we will face water shortages. During the drought of 2007, one town in Tennessee ran completely out of water, and the N.C. Drought Management Advisory Council reports that 30 cities in North Carolina were within 100 days of running out of water. The National Resources Defense Council conducted a study and found that one-third of all counties in the contiguous United States will face higher risks of water shortage by 2050, and in North Carolina, there are 15 counties that may be at high risk of water shortage. The city of Raleigh withdraws a large part of its water supply from Falls Lake, and it is expected that by 2040, the demand for water will be higher than the volume that the U.S. Army Corps of Engineers will currently allow the city to withdraw.

Q. Where does the water that comes into our homes come from in the first place? How is water recycled once we use it?

A. Many cities in the Southeast use surface water for their water supply. These cities store water in a reservoir or lake, and control the amount of water that is released, so that there will be water stored in the summer when demands are higher. Many households in rural areas use groundwater and pump water from local wells. Once we use water, the wastewater from showers, sinks, and toilets flows through underground pipes to the wastewater treatment plant, where it is treated using microbes and chemicals, which remove waste materials. The cleaned water is returned to streams and rivers. Many communities reuse wastewater through “de facto reuse,” meaning they draw water from a river or lake that includes wastewater from upstream communities. As a result, it is possible that people could end up drinking the same water that neighbors upstream took a shower in the day before.

Q. What aspects of water recycling and conservation do you study?

A. In my research, I study how governments and households make decisions to use or conserve water. We build computational models to evaluate how effective drought response plans – such as restricting outdoor water use – are at reducing demand and saving water. One important question for providing water is how people will use recycled water. In my research, we work with social scientists to understand how people in a community may perceive the risks and benefits of using recycled water, how they adopt the use of recycled water when it is made available for watering lawns and gardens, and how infrastructure projects should be planned to make recycled water available.