Early in 2011, the EPA contacted Alliant Energy about concerns at the Burlington facility. Alliant Energy tasked Aether DBS to further investigate the CCR facility, evaluate existing conditions, and submit a report on the condition of wet CCR storage. Aether DBS’ June report modeled  the stability of the CCR settling ponds under 100-year storm flow conditions and for both seismic and rapid drawdown induced loadings.  Aether DBS advanced soil borings in several locations critical for stability, and evaluated subsurface soil conditions.    A static analysis was performed, and earthquake liquefaction and stability was also assessed.  The finding of these studies was that the ash ponds at the Burlington facility safely met the required standards.

The EPA agreed with Aether DBS’s findings, and as such, determined than an AOC was not necessary for further investigations at the site.

In a July 5 letter to Alliant Energy, the EPA stated, “The EPA very much appreciates Alliant’s cooperation and prompt attention to this matter, as well as the quality of the work performed.  Alliant’s and Aether’s openness, attention to collecting reliable data and presenting it in a professional, well-organized manner made these discussions go very smoothly.”

Based on the recommendations within the report, Alliant is moving forward with additional activities at the site which have been accepted by EPA.