DAYTON — Recent erosion in the spillways at California’s Oroville Dam has led to massive evacuations and fears of a dam failure. The Miami Conservancy District (MCD) owns five flood protection dams in the Miami Valley—Germantown, Englewood, Lockington, Taylorsville and Huffman. Could something like what’s happening at Oroville Dam happen here?
It’s possible but not likely.
“MCD has caretakers who inspect our dams and levees on a regular basis,” says Kurt Rinehart, MCD chief engineer. “Our engineers routinely inspect our dams, and the state of Ohio inspects our dams on five-year cycles. Having said that, our dams are man-made structures and can never be 100-percent guaranteed. Reinvestment in our infrastructure is important.”
MCD has addressed vulnerabilities – such as underseepage – at the dams as they have been identified. Since 1999, MCD has spent $21 million in capital improvements to ensure the 95-year-old dams’ performance for generations to come.
There are more differences than similarities between Oroville Dam and MCD’s dams, including:
• The retarding basins behind MCD dams begin to store water once the river rises above the concrete conduits (openings in the base of the dams). It would take 14 inches of rain over a three-day period across the entire 4,000-square-mile Great Miami River Watershed before water would flow over MCD dam spillways.
• Oroville Dam is the tallest dam in the U.S. at 770 feet. The tallest of MCD’s dams is Englewood Dam at 110 feet.
• The spillways at Lockington, Taylorsville and Huffman dams are concrete structures. They are built directly above the concrete conduits (openings at the base of the dams) and are part of the same concrete structure. The Germantown and Englewood spillways are separate structures. The Germantown Dam spillway is north of the dam while the Englewood Dam spillway is attached to the dam at the western edge of the earthen embankment.
• The spillway at Oroville Dam is hundreds of feet high while the spillway at Englewood Dam has about a 6-foot drop. Any water flowing over the Englewood Dam spillway would have significantly less force, less speed and less potential for erosion. Germantown Dam doesn’t have a drop in its spillway, and serves more as a pass-through for the floodwaters.