Spring Hollow Reservoir and River Intake
Roanoke, VA

During the 1980's, a severe drought occurred across the state of Virginia. Working with local governments, the State Water Control Board selected the Spring Hollow pumped-storage reservoir as the best source to meet the water supply needs of the Roanoke Valley through the year 2040.

The County selected HSMM to provide all design and construction administration services for the new dam, pump station, and associated structures. Now complete, the project provides Roanoke County with an additional seventeen million gallons of water each day, enough to meet the forecasted demand. 

The system keystone is a 74-meter-high Roller Compacted Concrete (RCC) dam, one of the tallest in the United States, and the tallest east of the Mississippi. Its construction required a combination of unusual and adaptive design criteria, strict specifications for on-site materials processing, and a very experienced and creative contractor.

HSMM addressed a number of significant issues during the planning and design of the project, including computer modeling to determine the working storage and pumping requirements; environmental concerns relative to the impact of the project on the Roanoke River; geological and hydrological investigations and analysis; evaluation of alternative types of dams and dam designs to assure a safe, functional, and economical structure; implementing an RCC mix design program prior to bidding to determine the suitability of on-site materials for use in the dam construction and to verify that specification requirements would be met; and completing a preconstruction grouting program during the design phase to demonstrate that seepage in the reservoir area could be effectively controlled by grouting.