Lake Mount Union Dam Rehabilitation

The Lake Mt. Union Dam, constructed in the 1920's, is an Amberson type concrete buttress dam.  The dam, 320 feet long and 33 feet high, is situated on Singer's Gap Run.  The dam impounds water for the Mt. Union area water system.  Recent dam inspections revealed significant concrete deterioration that threatened it’s structural integrity.  The water authority used the services of Gwin, Dobson & Foreman, Inc. because of the firm's experience in dam safety and rehabilitation projects.

The project included the following state-of-the-art rehabilitation features:

• Downstream channel grading and armouring to channelize drainage, prevent downstream erosion and eliminate freeze/thaw action near buttresses.
• Concrete rehabilitation including surface preparation and chipping (where designated), pressure mortar surfacing and guniting, concrete bonding application, chemical grouting of structural cracks, cementitious waterproofing and penetration sealer application, slab and inclined joint repair, joint filler and flowable/trowel grade mortaring.
• Dam appurtenances repair including new intake and outlet valves, crest and spillway overflow section rehabilitation, reinforcing steel repair, underwater investigation/repair of intake structure, surface preparation, coating of pipes/valves and new access with aluminum stairs and handrails.

The project was completed on time and under budget.  It is one of the outstanding examples of a buttress dam rehabilitation in PA.