Case Study: Water and Wastewater Utilities Planning for Climate Change CITY OF KEENE, NEW HAMPSHIRE Background The city of Keene provides drinking water and wastewater services to approximately 23,000 residential customers and various large water users in Keene, NH, including two universities and a regional medical center. Average water demand at the water treatment plant (WTP) is 2.2 million gallons per day (MGD), increasing to 2.5 MGD during the summer months. The city of Keene's surface water comes from the Woodward and Babbidge Reservoirs which are located at a higher elevation in the watershed than the WTP. In addition to the reservoir, the city has four groundwater wells that are used to supplement the surface water predominantly during the spring and summer. Climate Threats The city of Keene has considered a number of climate change threats that may impact their operations. The city is primarily concerned with the impacts of changing precipitation and extreme rainfall events on water quality, specifically turbidity and Total Organic Carbon (TOC) in the Babbidge Reservoir. Increased turbidity and TOC of the raw surface water can impact the city's ability to treat the water, and occasionally may require switching entirely to their groundwater source until the turbidity drops. The city estimates that they have experienced at least five 500-year or larger precipitation events since 2005 along with more frequent deluge events where more than two inches of rain can fall in one hour. Extreme rainfall events in 2013 and 2015 prompted the city to adjust their operations to meet regulatory requirements during the events. Planning Process To better understand the vulnerabilities of their water resources to extreme precipitation events, the city of Keene engaged in a series of webinars and an in-person meeting to conduct a climate change risk assessment using the U.S. Environmental Protection Agency's (EPA) Climate Resilience Evaluation and Awareness Tool (CREAT). The assessment brought together individuals from the city of Keene and EPA staff to think critically about potential climate impacts, priority assets and possible adaptation options. The city of Keene is using their assessment to learn more about the impacts of climate change threats on their drinking water treatment and distribution system. Adaptation Measures Using CREAT results, the city of Keene was able to evaluate the performance and costs of additional short-term and long- term adaptation plans coupled with current measures that, if implemented, will provide additional protection to the drinking water treatment facility and distribution system. The city will continue to use the results of their CREAT assessment to underpin some of the decision-making during the planning process cycle. See the table below for all potential adaptive measures that were considered. City of Keene, New Hampshire Case Study — Page 1 xvEPA ------- Case Study: Water and Wastewater Utilities Planning for Climate Change TYPE POTENTIAL ADAPTIVE MEASURES Short-term Plan Beaver management plan to reduce organic material Improvement of emergency generator stand-by capacity Improve water quality models to better understand quality degradation in order to maintain continued drinking water service to customers Watershed management plan to improve the ability of the City to continue to monitor water quality in the event of high turbidity and TOC Long-term Plan Replace treatment with Dissolved Air Flotation/Filtration (DAFF) to improve the ability of the City to continue to treat raw water in the event of high turbidity and TOC Identify additional groundwater sources in the event the Babbidge Reservoir was not usable during an extreme event Contact Information For more information regarding the city of Keene's climate adaptation planning, contact Donna Hanscom at dhanscom@ci.keene.nh.us. City of Keene, New Hampshire Case Study — Page 2 oEPA Office of Water (4608T) EPA 810-S-16-004 January 2017 ------- |