Authorized by the Flood Control Act of 1944, East Branch Clarion River Lake is one of 16 flood control projects in the Pittsburgh District. An important link in a system of flood control projects, East Branch provides flood protection for the Clarion River Valley as well as the lower Allegheny and upper Ohio Rivers.
East Branch Lake has the capability to store the equivalent run-off of 21.84 inches of precipitation from its 72.4 square mile drainage area. Since its completion in 1952, East Branch Dam has prevented flood damages estimated to be more than $98 million. If all previous years’ benefits are estimated to current dollar value, then the cumulative flood risk management benefits provided by East Branch is equivalent to $456 million. The dam’s capacity to reduce flood damages was dramatically demonstrated during the June 1972 floods resulting from Tropical Storm Agnes when more than $20 million in damages were prevented by East Branch alone, equivalent to $139 million in today’s dollar value. The average annual flood risk management benefits at East Branch are estimated at $6.5 million. When compared to the flood control benefits which have resulted, the construction costs of $9 million appear small.
East Branch also stores water to be released downstream during dry periods. These releases of water have the effect of improving water quality and quantity for domestic and industrial use, navigation, recreation, aesthetics and aquatic life.
Since issues with the dam were found in 2008, the Pittsburgh District has implemented various interim risk reduction measures, one of which was to lower the summer and winter pool levels in order to reduce hydraulic loads on and within the dam embankment. This interim water control plan reduces the normal recreation pool of 1670 NVGD to 1650 NGVD and a target winter pool level of 1623 NGVD. This current measure will continue to be undertaken until a dam safety long-range strategy implemented. Go to East Branch Interim Risk Reduction Project page.