Colorado regulators are reviewing Xcel Energy’s final plan to clean up groundwater contamination caused by decades of coal ash disposal at the Valmont Power Station. The project, which could begin construction as early as late summer, follows years of contamination that migrated beyond the company’s property and was detected in at least one nearby residential well.The proposed system would pump contaminated groundwater from beneath the site and transport it for treatment, a first-of-its-kind project in Colorado. But environmental advocates say the cleanup may fall short if a second coal ash landfill near the power plant is also contributing to the pollution. Almost a century of coal burning at the Valmont Station left behind 1.6 million cubic yards of coal ash stored in landfills just east of Boulder. The waste contains contaminants including arsenic, lead and chromium.
A Boulder Reporting Lab investigation found that a coal ash landfill built at the Valmont site in 1993 has contaminated groundwater since at least 2017. Drawing on Xcel’s own monitoring data, the investigation documented coal ash in contact with groundwater, elevated levels of lithium and selenium in monitoring wells, and a contamination plume that has gradually migrated toward residential properties east of the site. Xcel also found lithium above safe levels in at least one nearby homeowner’s well.
