The U.S. Army Corps of Engineers Pittsburgh District is working to investigate the cause of a recent fish kill downstream of Youghiogheny River Lake in Somerset County, Pa.
The Corps has determined there is no risk to human life and safety.
What is known is approximately 220 brown trout measuring 12 to 18 inches were reported found dead today in the trout hatchery pens located at the outflow of Youghiogheny Lake.
Review of the water quality data, collected at the U.S. Geological Survey gauge in the Youghiogheny River near the pens, showed that the total dissolved gas saturation level was above the 105 percent dissolved gas saturation threshold when the kill occurred, which may have caused fish to be distressed or killed.
Upon notification of the event, at approximately 8:30 a.m., Pittsburgh District Water Management and Water Quality Units directed the operator of the hydroelectric plant at Youghiogheny Dam to discontinue hydropower generation. The operator, D/R Hydro Company in Confluence, Pa., was instructed to divert the flow away from the turbines, immediately mitigating the gas supersaturation and reducing saturation levels to 102 percent, which falls in the normal zone.
District biologists will be on site tomorrow to conduct a water quality survey and to assess the effects of the hydropower shutdown on the wild and penned fish.
At this time, the district attributes the kill to nitrogen supersaturation, which was detected at the USGS gauge. The district has directed D/R Hydro to remain offline until further notice in order to facilitate a final determination of cause and mitigate any further effects.
Pittsburgh District’s 26,000-square miles include portions of western Pennsylvania, northern West Virginia, eastern Ohio, western Maryland and southwestern New York. Our jurisdiction includes more than 328 miles of navigable waterways, 23 navigation locks and dams, 16 multi-purpose flood control reservoirs, 42 local flood protection projects and other projects to protect and enhance the Nation’s water resources, infrastructure and environment.