HARRISBURG – The Department of Conservation and Natural Resources (DCNR) has announced that it plans to temporarily elevate the lake level behind the George B. Stevenson Dam at Sinnemahoning State Park in Cameron County to collect data needed for a rehabilitation project for the dam.
“If weather and spring snow melt conditions don’t cooperate, we will decrease the volume normally released from the dam to raise the lake levels an additional 35-40 feet,” DCNR Bureau of State Parks Director Dave Kemmerer said. “Park visitors should be aware that the controlled elevated lake level is temporary and should take place during the month of March. It is anticipated that the lake will be back to normal pool levels before the start of trout season in April.”
The George B. Stevenson Dam is owned, maintained and operated by DCNR as part of a comprehensive four-dam initiative to control flooding on the West Branch of the Susquehanna River.
Of the four, the George B. Stevenson Dam is the only one not owned, maintained and solely operated by the Army Corps of Engineers. DCNR does operate the dam in cooperation with the corps during high water and major flooding events.
Annual inspection reports required by the Department of Environmental Protection show that the dam is in good condition and well maintained. Under normal conditions, the dam is considered safe and there is no need for concern.
An investigation by Gannett Fleming into increasing water storage behind the George B. Stevenson Dam for release during times of drought pointed to the need for additional information related to conditions that could occur during times of elevated pool levels.
DCNR is taking steps to make sure the dam remains stable when water is stored at major flooding elevations.
Data has been collected by DCNR personnel during various stages of low and high water events. After reviewing the collected data, DCNR contracted Schnabel Engineering of West Chester to develop plans and specifications for remedial action.
Schnabel Engineering is finishing a subsurface investigation and installation of piezometers on both slopes of the dam. Piezometers are devices used to explore water pressure or water flows below and through the surface of the earth. These vibrating wire piezometers will provide DCNR with real time data on soil and rock foundation conditions and water movement occurring within the dam during a high water event. The information will be used to finalize design for any repairs to the dam and also will help in fine tuning an Emergency Action Plan related to the dam.
Design should be completed by January 2014, and rehabilitation work will start in late spring or early summer of 2014.
Weekly reports on lake elevations will be posted on the DCNR/Sinnemahoning State Park webpage at www.dcnr.state.pa.us. Choose “Find a Park,” then “Sinnemahoning,” and click on “Advisories.”
For more information, contact the Sinnemahoning State Park office at 814-647-8401 or email sinnemahoningsp@pa.gov.