Mayfield, NY – Conklingville Dam and Great Sacandaga Lake minimized the effects of heavy rainfall associated with the remnants of Hurricane Irene, preventing flooding on the Hudson River from Hadley to Fort Edward, and reducing the severity of flooding from Fort Edward to Albany.
The Great Sacandaga Lake watershed received approximately 5.5 inches of rain from Irene causing the reservoir to rise about 3 feet. Precipitation from the storm produced sharp rises in the Sacandaga and Hudson River. Inflow to the reservoir peaked at more than 40,000 cubic feet per second (cfs) during the afternoon on August 28 and produced an average of 20,000 cfs for the day.
Without the benefit of flood protection and storage capacity at Great Sacandaga Lake, the Hudson River would have exceeded flood stage at Fort Edward by more than 5 feet. By reducing the flow in the Hudson River by at least 20,000 cfs, the flood protection benefit provided by the reservoir reduced the flood stage at Waterford, Green Island, and Troy by nearly 2 feet.
The elevation of the Great Sacandaga Lake was lowered more aggressively, consistent with the Offer of Settlement operating rules, to an elevation of 762.6 feet by the morning of August 28 in anticipation of significant inflow. Increasing the release of water from the reservoir for about four days before the storm provided an additional 700,000,000 cubic feet of storage capacity.
Great Sacandaga Lake is poised to efficiently deal with current tropical rain events following Irene. The peak elevation of the reservoir resulting from the most current rainfall is estimated to be approximately 770 feet above sea level. Release of water from Great Sacandaga Lake will begin as soon as the flow rate of the upper Hudson River allows.
The Hudson River – Black River Regulating District is a State of New York public benefit corporation which provides river regulation, including flood protection and low flow augmentation, in the Hudson and Black River watersheds through the operation of water storage reservoirs, including the Great Sacandaga Lake, Indian Lake, Stillwater Reservoir and the Fulton Chain of Lakes.