The state Department of Conservation and Natural Resources has ruled out repairs for the dam that once formed Gunter Valley Reservoir in Franklin County.
DCNR Acting Secretary Ellen Ferretti said fully rehabilitating Gunter Valley Dam to modern safety standards would cost an estimated $20 million to $25 million, so the dam will be breached and the stream channel will be restored.
The 50-year-old dam across Trout Run in Tuscarora State Forest was plagued with cracks and leaks, and the 26-acre lake once formed by the dam was drained by DCNR in October 2009.
Ferretti said projected rehabilitation costs increased substantially as DCNR learned more about the dam's embankment, foundation and control tower problems, as well as an inadequate spillway.
The reservoir and surrounding 3,000 acres were purchased by DCNR from the Shippensburg Borough Authority and added to the Tuscarora State Forest in 2003.
The borough stopped drawing water from the reservoir in 2007, and it no longer is necessary to meet the borough's needs, Ferretti said.
The dam breach and required stream-channel restoration in the impoundment area will be subjected to further site studies before bids are sought.