Client: West Carroll Township Water & Sewer Authority
Year Completed: 2005
Project Cost: $1,150,000
Faced with the prospect of either losing its main water supply or building and unaffordable project, the West Carroll Township Water and Sewer Authority (which operates on severely limited financial resources) turned to Gwin, Dobson & Foreman, Inc. to design a cost effective solution for the deteriorated Bakerton Dam. The dam, 455 feet long and 25 feet high, is located at the headwaters of the W. Branch of the Susquehanna River.
Bakerton Dam, constructed in 1922, was a composite earthen/Amberson concrete slab and buttress dam. Inspections revealed significant concrete buttress deterioration with resulting leakage and instability. In fact, the PADEP Division of Dam Safety considered Bakerton Dam as the most unsafe and highest hazard dam in the state and ordered a partial breach of the structure. Unique features of the project included the following:
- The existing concrete slabs/buttresses were incorporated in the new compacted earth dam, thus combining structural and waterproofing elements with a more stable and durable earth embankment
- It is believed that the Bakerton Dam represents the first Pennsylvania application of incorporating an existing slab and buttress structure into a new earth embankment dam.
- The new concrete spillway and crest cap provide overtopping protection during the probable maximum flood. Since the normal pool was lowered for these purposes, the reservoir basin was dredged (20,000 cubic yards) to compensate for loss of reservoir storage capacity
- A low cost alternative was devised to provide upstream intake control. Precast concrete culvert boxes were inverted and stacked for a multi-port intake tower.
- Pressure mortar surfacing was applied to the upstream concrete deck.
The project was constructed well within budget and on schedule while achieving full compliance with state dam safety rules.