Citizens Energy Group uses both surface water and ground water as sources of supply for its drinking water utilities. While surface water contamination is often visible, adverse impacts to ground water can be more difficult to detect.
The Indiana Department of Environmental Management (IDEM) has a mandatory Wellhead Protection Program designed to safeguard ground water resources that are used as a public drinking water supply.
Citizens has 12 wellfields from which it collects, treats, and distributes drinking water to customers. Each wellfield has a wellhead protection area (WHPA) delineated by use of groundwater hydraulic modeling tools and a professional hydrogeologist. Delineation of the WHPA establishes the one-year and five-year time of travel (TOT) boundaries. For example, a spill of a hazardous substance in the one-year TOT (T1) area could reach the wellhead in approximately one year; similarly, a spill in the five-year TOT (T5) area could reach the wellhead in approximately five years.
Education and outreach materials are designed to encourage residents and business owners within the WHPAs to reduce potential impacts to ground water by using and storing chemicals and petroleum products properly and promptly responding to spills of hazardous materials.
IDEM’s Wellhead Protection Rule requires Citizens to update each wellhead protection plan on a five-year cycle. The update includes review of the T1 and T5 WHPA boundaries. During 2017 and 2018, five of Citizens’ WHPAs were due for re-examination. Based on factors such as pumping rates, water use patterns, and improved modeling tools, the delineation boundaries in four of the five WHPAs in Marion County changed.
Citizens’ Environmental Stewardship, Water Operations, and Wet Plant Engineering staff worked alongside IDEM’s Drinking Water Branch and American Structurepoint (hydrogeologist) for approximately one year to determine new T1 and T5 areas. In March 2019, Citizens received IDEM-approval for the new delineation boundaries of its four largest WHPAs.
“Roughly 30 percent of drinking water for Indianapolis, and all of the drinking water for Westfield, comes from ground water,” said Ann McIver, Director, Environmental Stewardship. “Protecting ground water through the Wellhead Protection Program helps ensure this water is available to meet the needs of our customers.”
