According to an Army Corps of Engineers hydraulic engineer, the storm water collected in the Conemaugh Lake Dam in the past few days would have been enough to cover the entire City of Pittsburgh in five feet of water.
Instead, the Corps’ recent operations at Conemaugh and the Loyalhanna Lake dams, east of Pittsburgh, cut down the crest of the Kiskiminetas River by 17 feet, preventing what would have been the second highest flood on record.
Without the reservoirs, the Kiski’s crest would have risen five feet over flood stage to 30 feet instead of cresting at 13 feet, corps officials said.
At that level, the Vandergrift area would have realized its largest flood event since 1936, before the region’s system of federal flood risk management reservoirs were built.
“Conemaugh saw the most dramatic spike, rising more than 65 feet in three days,” said Charles Kottler, hydraulic engineer for the Pittsburgh District.
The operation of the district’s 16 dams in the headwaters of the Upper Ohio River Basin also reduced the flood risk along other waterways as remnants of Tropical Storm Gordon dropped nearly five inches of rain in some areas over the weekend.
“Our water management team and dam operators continue to work around the clock to manage our reservoirs,” said Col. Andrew Short, commander for the Pittsburgh District. “These storms can change course quickly or intensify unexpectedly so we’ll continue to monitor and adjust as the forecast develops and the potential for additional rainfall exists.”
The district’s Youghiogheny Dam reduced the severity of flooding along the Youghiogheny River — which reached 16.3 feet — sparing communities such as Connellsville and Suterville an additional two feet of flood water.
Reservoir operations of Berlin Lake, Mahoning River and Michael J. Kirwan Dam and Reservoir cut the crest by seven feet at Leavittsburg along the Mahoning River in eastern Ohio.
Currently, the district is releasing water to create flood storage space in the dams to capture potential runoff from incoming storms. Corps officials cautioned residents that rivers will remain artificially elevated and fast as the district discharges from its dams.
Patrick Varine is a Tribune-Review staff writer. You can contact Patrick at 724-850-2862, [email protected] or via Twitter @MurrysvilleStar.