Dave Johnston Power Plant has 32 groundwater monitoring wells, 29 of which have been polluted above federal advisory levels based on samples collected between September 25, 2015 and October 19, 2019. Groundwater at this site contains unsafe levels of sulfate, molybdenum, cobalt, boron, arsenic, lead, radium, fluoride, selenium, cadmium, lithium and thallium.Site description
PacifiCorp's Dave Johnston Power Plant opened in 1959 and is located on the banks of the North Platte River in Glenrock, Wyoming in Converse County. It has three coal-fired generating units that can produce producing 922-MW of electricity. PacifiCorp has set the facility for retirement in 2027. The plant has two CCR units: Expansion Landfill and Ash Pond. The Expansion Landfill consists of three stages, each with a planned design life of 5 years. The total area of the landfill is approximately 122.6 acres. There is one retention basin that collects runoff from all three phases. The Ash Pond is divided to two individual ponds, 4A Pond and 4B Pond. Each pond has an approximate surface area of 19.5 acres and an approximate storage capacity of 144.6 acre-feet. Dave Johnston Power Plant is among the U.S. Environmental Protection Agency's list of potential damage cases, indicating that coal ash disposal at the site has potentially polluted groundwater or surface water at levels which threaten human health and the environment.