water quality
MARK W. L E C H E VA L L IE R
The impact of climate change on water infrastructure WHEN EVENTS THAT WERE HISTORICALLY CONSIDERED TO BE “100-YEAR” EVENTS HAPPEN MORE AND MORE FREQUENTLY, UTILITIES MUST PREPARE FOR A NEW NORMAL.
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limate change is greatly affecting weather patterns and the world’s ecosystem and, in particular, posing significant challenges to the world’s water supply. Causing poor water quality and scarcity and putting significant stress on our water infrastructure, climate change is having a profound effect on how communities can reliably access clean water. Climate change generally refers to changes in average temperature, precipitation, and weather intensity. Experts agree that the main cause of climate change is the increasing levels of greenhouse gases in the atmosphere. Although a certain level of greenhouse gases is essential to maintaining the temperature of the earth, higher levels raise the earth’s temperature, causing climate change. Water sources are affected by climate change in three general ways: changes in annual rainfall; increases in sea levels; and increased runoff, which results in decreased raw water quality. Changing climate also poses a variety of risks to all US water infrastructure. It manifests itself through extreme weather events. The infrastructure that makes up water and wasteLECHEVALLIER | 106:4 • JOURNAL AWWA | APRIL 2014
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water systems is built for resiliency and sustainability of operations during weather events or other circumstances that could potentially interrupt service. When events that were historically considered to be “100-year” events happen more and more frequently, utilities must prepare for a new normal. These extreme events are occurring or being exceeded more regularly. As a result, the past may no longer be a reliable predictor of the future. For example, within a short time frame, the Mid-Atlantic states have experienced multiple significant weather events, including the Christ-
utilities can work to mitigate current contributing factors when possible. Climate change can have a variety of effects on water utility infrastructure, which can drive many different types of solutions: • More frequent and more intense heat waves and droughts can result in higher peak water use and reduced water supplies, which can then result in the need for increased plant capacity and development of alternative water supplies along with more aggressive water conservation and demand management measures. • More frequent and intense rainfall events with wider variability
Causing poor water quality and scarcity and putting significant stress on our water infrastructure, climate change is having a profound effect on how communities can reliably access clean water. mas Blizzard in 2010, Hurricane Irene, Tropical Storm Lee, the October Northeast snowstorm in 2011, the Mid-Atlantic/Midwest Derecho, and Hurricane Sandy in 2012. Additionally, severe droughts in the Midwest in 2010 caused the ground to shrink and crack, leading to an increased number of water main breaks. In 2012, low rainfall and extreme heat led to crisis drought conditions in many states, with the Midwest hit hard again. Each weather event raises the question: Is it climate change or is it just freak weather? There is, in fact, a difference between climate variability and weather, and according to the National Aeronautics and Space Administration, that difference is time. Weather is short-term, and climate “change” is long-term, typically covering a 30-year span. There are two approaches that can be used to address climate change: (1) utilities can adapt and plan for the effects of long-term climate variability and (2) 80
can result in the need to provide greater flood protection and larger dam spillways. • More extreme storms often lead to more frequent and more widespread power outages, which can affect the ability to treat and pump water, resulting in the need for more emergency standby generators and alternative fuels. • Water quality effects from higher runoff and salinity can drive the need for more advanced treatment processes and alternative-supply development. However, it is important to put climate change in the proper context in terms of overall risk management. American Water sees climate change as one more risk that should be assessed and prioritized along with various other risks that can affect a system’s ability to provide safe, adequate, reliable service. High-priority issues typically include critical assets in need of repair/replacement, impending sup-
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ply deficiencies, treatment processes aimed at meeting regulations, and health and safety issues. Recent weather patterns and the issue of aging infrastructure are causing utilities to review traditional planning and design criteria. The socalled new normal has led experts to look beyond traditional reliability and emergency planning into a world that needs the speed of recovery and resiliency for much more widespread weather events. Updating event-response planning and procedures to keep up with the increase in extreme weather is just as important as preparing for long-term changes in climate. In the past few years, American Water has found that its former planning standard of 50% of an average-day demand for standby power is no longer adequate for maintaining service for extended time periods after an extreme event. As a result, it has systematically added additional standby power capacity, in addition to using a more diverse and reliable mix of emergency fuel supply. American Water emphasizes, however, the conclusions from its risk assessment models and planning studies do not always result in a decision to build additional infrastructure. Often an operational solution or well-scoped emergency plan could be a more effective solution to a particular scenario. In many cases, a combination of solutions, ranging from capital to operational, provide the best resiliency against extreme events. Through proper planning, identifying critical assets, assessing and prioritizing risks, and by providing a variety of solutions, we attempt to reduce the probability and impact that extreme weather events will have on our ability to maintain service to our customers. Planning activities are performed frequently, so the latest assumptions and information available on climate science are taken into consideration. With the uncertainty associated with climate-change projections, it is impor-
tant to consider a broader array of outcomes through methods such as scenario planning in which multiple outcomes are considered. American
alternative water supplies, and public education will all be necessary in order to make significant progress. Because the issues are vast, actions
Climate change affects water sources in three general ways: changes in annual rainfall; increases in sea levels; and increased runoff, which results in decreased raw water quality.
stewardship and greenhouse gas control programs. Recipient of AWWA’s George Warren Fuller Award and the Abel Wolman Award, among others, LeChevallier has written more than 100 research papers, most for peer-reviewed journals. He currently serves as chair of the Journal’s Peer Review Editorial Board. http://dx.doi.org/10.5942/jawwa.2014.106.0066
ADDITIONAL RESOURCES Water puts a high emphasis on solutions that can address multiple issues in a cost-effective manner. For example, when certain infrastructure is at the end of its useful life, opportunities are considered to not only renew this infrastructure but also to design for potential effects of climate change. Global climate change will not only have widespread implications for water utilities but also for communities and businesses around the world. An important step in addressing the challenges of climate change is identifying ways to limit greenhouse gas emissions and educate people about these measures. Water utilities must continue to assess their own contributions and track greenhouse gas emissions to find ways to reduce their effect on the environment. There are a number of strategies for energy efficiency, starting with regular energy audits; implementation of renewable solar, wind, and bioenergy; use of high-efficiency pumps and electrical systems; and application of lowenergy technologies. Although the water utility industry must demonstrate leadership here, it cannot succeed alone. A unified effort between government, businesses, and consumers is needed to implement near-term solutions and develop broad strategies to address the adverse effects of climate change on the water industry and the global water supply. Policy changes, funding for infrastructure, development of
must be undertaken by both public and private sectors in order to effectively meet and address the challenges of climate change that lie ahead. Hurricane Sandy gave us a hard reminder of the immense power of water. There are many uncertainties associated with changing climate patterns and their effects on water, but there is little doubt that climate variability could seriously disrupt water quality and supply unless we respond with adequate planning and risk assessment. The bottom line is that communities, no matter how large or small, need to come together to better plan around both climate variability and weather.
ABOUT THE AUTHOR Mark W. LeChevallier is director, innovation and environmental stewardship, American Water, 1025 Laurel Rd., Voorhees, NJ 08043 USA; mark.lechevallier@ amwater.com. LeChevallier also directs environmental compliance programs for American Water, including the development of environmental management plans for more than 1,000 operating centers, environmental audits to ensure compliance, development of a national cross-connection control program, and implementation of environmental
Assessing and Adapting to the Impacts of Climate Change on Our Water Resources and Infrastructures (PDF-PowerPoint). 2013 AWWA Sustainable Water Management Conference & Exposition. Catalog No. SOURCES_0078488. Pratt, J., 2013. Changing Mindsets to Promote Sustainable Water Operations Under Climate Change (PDFPowerPoint). 2013 AWWA Sustainable Water Management Conference & Exposition. Catalog No. SOURCES_0078487. Renner, R., 2013. Climate Change, Extreme Weather, and Water Utilities: Preparing for the New Normal. Journal AWWA, 105:11:44. http://dx.doi. org/10.5942/jawwa.2013.105.0159. Visit the AWWA store at www.awwa. org/store for more.
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