Geotechnical Engineering
Lake Blackshear Dam Breach Repair
The
Lake Blackshear Dam is the water retaining structure for Plant Crisp
Hydroelectric Station which is owned and operated by Crisp County Power
Commission.
Provide geotechnical engineering services to investigate subsurface conditions, assess the integrity of the portion of the north embankment that did not breach, and design a replacement of the breached section. Devine Tarbell & Associates, Inc.’s (DTA) staff planned and conducted a subsurface investigation consisting of 15 borings and several test pits. Testing performed during the site investigation included standard penetration tests, rising and falling head tests to determine in-situ permeability, and packer tests to determine in-situ hydraulic conductivity of the limestone bedrock.
An engineering analysis was conducted using the results of the subsurface investigation. pockets of loose material. Computer slope stability analyses were performed on the cross sections of the proposed breach section to verify compliance with FERC criteria.
The geotechnical aspects of the project were the subjects of papers presented at Waterpower ’95 and at the Association of State Dam Safety Officials (ASDSO) 1995 Convention.