CARTHAGE, Tenn. — Jim Carter, who leads hydropower design activities in the Nashville District Civil Design Branch Mechanical and Electrical Section, inspects the Cordell Hull Dam Switchyard here, March 6, 2012. A combined team from the Nashville District and the Hydroelectric Design Center in Portland, Ore., which is the Corps’ national center of excellence for hydroelectric and large pumping plant engineering services, is performing a district-wide assessment of the switchyards at nine hydropower project sites.