WorldWide Drilling Resource

30 DECEMBER 2021 WorldWide Drilling Resource ® RENEW - SUBSCRIBE NOW! Fort Collins Looks to Increase Water Storage Adapted from Information by the City of Fort Collins Utilities Halligan Reservoir is an existing reservoir on the North Fork of the Poudre River, 25 miles northwest of Fort Collins, Colorado. Even though conservation has reduced water demands, it is not enough to provide the resiliency needed to meet the growing service area’s needs. The Halligan Water Supply Project will enlarge the reservoir to meet demands of future Fort Collins Utilities customers and provide additional reliability for current customers. Without additional storage, future generations of water cus- tomers will be vulnerable to interruptions in availability and deliv- ery, particularly during emergency situations. In the event of a prolonged drought for the projected population and commercial growth within the established Fort Collins Utilities service area, current water supply of only 7100 acre-feet is inadequate to meet demand without water restrictions. Plans are to expand the reservoir from about 6400 acre-feet to roughly 14,500 acre-feet by increasing the height of the existing 70-foot dam by 25 feet, providing approximately 8100 acre-feet of additional water storage. Project benefits will include enlarging an existing reservoir instead of building a new one, creating fewer negative envi- ronmental impacts; providing year-round flows on the North Fork of the Poudre, leading to fishery and habitat improvements; rehabilitating an aging dam built in 1909, which will require repairs in the future; and requiring no energy, as it is a gravity-fed project with no pumping needed. The U.S. Army Corps of Engineers released a draft environmental impact statement (EIS) and a conceptual mitigation plan in late 2019, and will develop a final EIS before making a permitting decision about whether Halligan Reservoir can be expanded. The final EIS, conceptual mitigation plan, and permit decision is expected to be completed by 2022. More than just a dam project, the Halligan Water Supply Project is an envi- ronmental enhancement project. Colorado Parks & Wildlife will be the lead in focus- ing on impacts to fish and wildlife, while Colorado Public Health and Environment will focus on impacts to water quality with ongoing water quality sampling aug- mented to support analyses. A mitigation plan has been developed to help avoid or minimize impacts and compensate for those that are unavoidable. A large part of the plan focuses on improvements to the North Fork of the Poudre River ecosystem. Fort Collins Utilities is using a method of early contractor involvement where the project contractor is part of the design from the beginning. A field investigation was conducted, including dam and foundation drilling, to determine the integrity of the existing dam, along with the soil, bedrock, and groundwater conditions around the location of the enlarged dam. The inves- tigation also included an evaluation of onsite materials which may be used dur- ing construction. At least 30% of the design will be completed in 2022, with construction taking place from 2024 through 2025. Enlarged Halligan opera- tions are projected to begin in 2026, with the cost expected to be between $100 - $150 million, depending on the final project design, schedule, and require- ments. Scaling Halligan Dam to extract cores. ENV

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