||GEI Consultants, Inc., Centennial, CO.; Lockheed Martin Services, Inc., Edison, NJ.; Environmental Protection Agency, Washington, DC.
This report presents the results of a specific site assessment of the dam safety of seven impoundment embankment dams at the Apache Power Plant in Cochise, Arizona. These impoundments are Ash Ponds 1, 2, 3, and 4 (Ash 1, Ash 2, Ash 3, and Ash 4), Scrubber Sludge Ponds 1 and 2 (Scrub 1 and Scrub 2), and the Evaporation Pond. These seven impoundments comprise the Coal Combustion Waste Facility at the Apache Power Plant. Other coal combustion waste impoundments at the Apache Power Plant include the Low Volume Wastewater Pond, Cooling Tower Blowdown Pond, and the Coal Pile Retention Basin. The power plant also has a coal combustion waste facility that has been closed under Arizona Department of Environmental Quality (DEQ) requirements. The specific site assessment was performed on September 2 and 3, of 2009. These impoundments were assessed because their failure may result in significant economic loss, environmental damage, disruption of lifeline facilities or loss of life (significant or high hazard according to U.S. Environmental Protection Agency (EPA) classification). The specific site assessment was performed with reference to Federal Emergency Management Agency (FEMA) guidelines for dam safety, which includes other federal agency guidelines and regulations (such as U.S. Army Corps of Engineers (USACE) and U.S. Bureau of Reclamation) for specific issues, and defaults to state requirements where not specifically addressed by federal guidance or if the state requirements were more stringent.