Schnabel

Hickory Log Creek Dam

Cherokee County, GA

City of Canton, Georgia (25%), Cobb County-Marietta Water Authority (75%)

Alternative Analysis Dam Design Hydrologic and Hydraulic Analyses Geotechnical Investigation Geologic Investigation Construction Management Services

The Hickory Log Creek Dam is a new 188-ft high by 975-ft long roller compacted concrete (RCC) gravity dam. The dam is located on an 8.2 square mile drainage basin, and impounds a 411-acre reservoir. The dam and reservoir is part of a $100 million pump storage water supply project. The project was designed in two phases. Phase I consisted of the foundation excavation and improvement contract and also include site infrastructure improvements and stream diversion. Phase II consisted of construction of the dam and ancillary structures. Schnabel completed the geologic and geotechnical investigation in two phases. The Phase I program was implemented to gather information to select the most cost-effective type of dam for the project site. After the type of dam and configuration were selected, a more in-depth Phase II field and laboratory program was completed. The in situ field work included pressure meter testing of weathered rock and water pressure testing of the foundation rock. Schnabel designed a two-line grout curtain and seepage control cutoffs, and collection components based on data from the field program. The RCC dam included a 250-ft long spillway including a 110-ft section with six-ft high crest gates. The dam is design to pass the Probable Maximum Flood of 42,000 cfs. Due to topographic constraints, the spillway over the dam converges from 250 ft at the crest to 140 ft at the stilling basin. Schnabel, in conjunction with Utah State University, completed a 1:25 scaled model study of the spillway and stilling basin to confirm the spillway rating curve and optimize the design of the stilling basin, which resulted in significant cost savings for the project. The design and construction of the $46 million project was completed in 39 months.