Examining the impacts of drought on water resources and energy
Droughts in the Western U.S. make headlines worldwide, posing particular challenges for people living and working in the affected regions. Here’s a close examination of the effects of drought on available water resources.
The Effects of California Drought Vary by Location
People regularly discuss California when talking about long-term drought, particularly because the state often experiences prolonged water shortages. Some experts believe that rather than going through brief non-drought periods, the state is actually enduring a so-called emerging megadrought and has been for the last two decades.
Research conducted in 2020 examined nine Western U.S. states and parts of Mexico. The team started by looking at ancient droughts dating back to 800 A.D. It then scrutinized soil moisture records associated with observed weather events from 2000-2018.
Park Williams, a bioclimatologist and associate professor at UCLA involved with the study, remarked, “This drought that we’re in now over the last 22 years has been as severe as the worst 22-year periods of the worst megadroughts that occurred last millennium.”
However, sources outside of that research said water availability during a drought varies depending on location. One significant reason for that is that Southern California imports much of its water from elsewhere. Metropolitan Water District — a regional wholesaler — has had a 13-fold increase in the amount of water stored in Southern California since the 1980s. Other areas do not have such significant importation levels.
Water availability in California during a drought also varies due to area restrictions. Some experts say it may take a dry spell lasting years for Southern California authorities to impose usage curbs. However, in other places, residents already lack freedom regarding how they use water.
In Redwood Valley, located in a Northern coastal county within the state, there’s a 55-gallon-per-person daily limit. That leads people to shorten their showers and carefully select plants for their gardens, focusing on varieties that do not need much water.
Improving Water Availability Requires Exploring New Methods
Wastewater treatment plants — or now more commonly water recovery facilities — process about 34 billion gallons of wastewater per day in the U.S. The worsening effects of drought in the Western United States necessitated examining new ways of increasing water resources, including recycling sewage or wastewater to make it safe for drinking.
That is already a common practice throughout California, although some people needed time to get used to the idea. The state even has rules that allow sending purified wastewater directly from a facility to drinking water reservoirs.
Another more recent advancement could eventually change how wastewater processing occurs in the respective facilities. A research team at Washington University in St. Louis developed a single system to purify water while generating electricity. It relies on electrochemically active bacteria as a catalyst. Attaching bacteria to an anode before pumping wastewater into it makes it consume organic materials while releasing electrons. The team made the anode out of conductive carbon cloth, so it functions as a dynamic membrane.
Results showed that the combined effects of the bacteria and membrane filter 80 to 90% of organic materials, making the water suitable to release back into the environment or be treated for non-potable uses. Analyses also indicated that this process could generate at least half of the electricity typically used to clean water at a plant. Thus, besides promoting water quality, this option helps plants operate more sustainably.
The Effects of Drought Impact Hydropower
Researchers at North Carolina State University examined the ramifications of a long-term drought by looking at the effects of the one that happened in California from 2012 to 2016. They found that water scarcity can make power bills rise in areas that heavily depend on hydropower.
California uses hydropower for about 13% of its energy needs. However, the drought during the studied period led to less streamflow, precipitation and melted snow. That meant the state only got about 6% of its energy from hydropower during the worst of the drought. Relatedly, the increased temperatures caused a higher cooling demand.
The researchers concluded that the reduced hydropower generation cost three investor-owned Californian utility companies $1.9 billion, while the extra demand for cooling led to another $3.8 billion. They determined, unsurprisingly, that consumers would likely feel the effects of those expenses.
Another interesting finding indicated that doubling investments in other types of renewable energy did not offset the additional carbon dioxide emissions and fossil fuel generation associated with the drought. They confirmed that having more renewable energy during non-drought years has a positive effect on emissions. However, drought periods had higher emissions despite renewable energy utilization.
Increased Wastewater Reuse Requires a New Look at Conservation Mandates
Newer trends like wastewater recycling to increase drinking-water resources during droughts also make it necessary to examine how some imposed conservation practices may have unintended consequences. That was a finding from research conducted by a team at the University of California, Riverside.
It analyzed 34 Southern California wastewater treatment plants, checking things such as monthly effluent flow and salinity levels. It also examined metrics including total potable water output and residential use of the liquid. The team focused on the 2013-2017 drought, which required statewide limits on water use.
Their results showed an increase in wastewater salinity and other pollutants, plus a drop in volume. They clarified that the rules curbing indoor use created less water to recycle and reuse and reduced the water available for stream augmentation. They said returning the water left to streams could impact the flow and downstream water quality.
The researchers said their study’s outcomes emphasized the need to weigh the pros and cons of certain water conservations meant to mitigate the effects of drought. Otherwise, particular mandates could negatively impact availability elsewhere in the state. Water supply concerns an interconnected system, and it is sometimes challenging to understand all the potential effects of certain decisions.
Droughts Can Compromise Water Infrastructure
Much research involves studying the effects of California drought, likely because water scarcity affects that state more often than many others. However, the issue crops up in other places, too. For example, Eastern Washington state recently had the first-ever drought advisory of its kind issued there. It warned residents that conditions made a lack of water resources likely to happen.
The situation so far is not as urgent as in other Western U.S. states, largely due to the high snowfall in Eastern Washington that let people go skiing as late as May. The snowmelt helps farmers that rely on irrigation. However, some parts of the state feature dry-land farms that solely use rainfall to keep crops watered.
Regardless of someone’s location, droughts can harm existing water infrastructure. In one case, scientists used radar equipment to confirm that a section of the California Aqueduct had sunk by 20 centimeters in four months. That issue may mean irrigation canals carry less water than they initially could.
Farmers pumping groundwater for irrigation can cause pollutant accumulations, particularly as the water-filled layers of underground clay contaminate the liquid with arsenic. Concerns have also emerged that excessive pumping could eventually deplete the aquifers of usable water.
That impending issue pushed California state legislators to view aquifer protection as an urgent need. Unfortunately, it's not only an issue there. Sources indicate there are highly stressed aquifers in 17 countries. Many leaders will undoubtedly see what happens in California and use that knowledge to guide decisions made in their areas.
The Effects of Drought Are Not Always Immediately Evident
The research covered here and elsewhere highlights how detecting the water resource issues associated with drought is not always clear-cut. Moreover, the effects of California drought will become learning experiences for decision-makers located elsewhere in the Western United States.
Having a clearer understanding of drought will not stop excessively dry periods from happening. However, people can gain knowledge that helps them make proactive choices to minimize adverse outcomes.