U.S. Army Corps of Engineers’ Great Lakes and Ohio River Division Commander, Col. Steven J. Roemhildt speaks at the 2014 HydroVision conference in the Music City Center, Nashville, Tenn., July 22, 2014. The four-day event, which has been held for two decades, highlights the work of the U.S. Army Corps of Engineers, which is working on a $1 billion project to renovate aging hydroelectric generators across the region.