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Could Water be Stored Under Denver? Adapted from Information by Denver Water Denver Water has been drilling deep into an important question: Can it store small portions of its water underground to augment supplies in mountain reservoirs? The utility took another step toward finding an answer with a test project in the heart of the city. An exploratory 1800-foot well was drilled several hundred feet deep in the Congress Park area. It was a round-the-clock endeavor which took several weeks. The project was part of Denver Water’s “all of the above” strategy to ensure it can meet future demands in its service area. Combined with conservation and efficiency, new reservoir storage, water recycling, and other approaches, storing some water underground would increase the utility’s options as the region grows and climate change stresses water supplies. “Storing excess water underground in wet years would provide a savings account of sorts to help the community endure dry periods,” explained Bob Peters, water resource engineer for Denver Water. “It gives us another place to turn when supplies get tight.” This project comes after an earlier study, in 2015 and 2016, when Denver Water drilled boreholes at eight locations to better understand the rock composition underneath the region. Those findings were promising enough to lead Denver Water to this next step, the construction of a pilot well facility. Depending on what engineers discover from the exploratory well, operational wells could eventually be constructed and used to test injection and removal of waters, challenges associated with the process, and effects on water quality. The concept, known as Aquifer Storage and Recovery (ASR), is a more sophisticated version of what people have been doing for centuries around the world. Similar projects are in use or under study in several communities along the Front Range of the Southern Rocky Mountains, including Greeley, Highlands Ranch, and Castle Rock. “This method has been successful for other utilities on the Front Range, but more study is needed to learn about the aquifers under our feet in Denver,” said Peters. “This program will help us determine if pursuing ASR is a smart long-term investment for Denver Water. More study will likely be needed after this project is complete, but it is an important step.” Storing water underground is not a substitute for reservoir storage. For starters, Denver Water relies on its mountain reservoirs to capture water from melting snow before it can move it onward to treatment plants and other storage sites, including any future underground locations. And the volumes to be stored underground would be relatively small, in the 400-to-500 acre-feet range for each site which might be built. Compare that to Denver Water’s big mountain reservoirs storing volumes from nearly 50,000 to more than 250,000 acre-feet. Even so, it could be an important way to set aside water to supplement supplies in dry years. Keeping water underground also has the benefit of preventing evaporation. That said, there are also drawbacks. For example, water would need to be treated both before injection and after recovery, adding cost and complexity to water management. “Our long-term planning relies on an array of options; ASR has the potential to be one more part of a mosaic of solutions that ensures our customers have the water they need down the road,” remarked Peters. Exploratory drilling for an ASR study conducted by Denver Water. WTR Groundwater / Water Well by: Princeton Groundwater, Inc. Remediation Course June 13-17 ~ Las Vegas, NV phone: 813-964-0800 More education opportunities during events can be found by clicking here online at: Education Connection 27 MAY 2022 WorldWide Drilling Resource®