John R. Doutt Upground Reservoir
This reservoir is the largest geosynthetic-lined structure in the United States. S&ME worked as part of the team for the design and construction of the 9.2 billion gallon reservoir.
The 850-acre site required a composite liner due to the presence of shallow sand and gravel deposits and karst limestone. The composite liner consists of 18-inch thick compacted clay liner (CCL) overlain by a 40-mil thick Flexible Polypropylene (fPP). The geomembrane is overlain by a geotextile and an 18-inch-thick soil cover and spans over 37 million square feet across the floor of the reservoir terminating into the upstream embankment toe. This provided cost savings to the project. At the same time, it eliminated several potential issues including interface friction, and the potential for seepage through the liner system.
The project required active dewatering during construction to maintain lower groundwater levels. Our team performed groundwater monitoring and prepared designs to maintain levels below subgrade for any required over excavation. This forced the bidders to consider an active dewatering system and was specified to reduce potential disputes. S&ME also assisted in field engineering, submittal reviews, and design verification.
In addition to our integral role at the reservoir site, S&ME provided geotechnical engineering services and construction dewatering recommendations for an inflatable weir being constructed across the Scioto River, the 180-million gallon per day pump station, and more than two miles of 60-inch-diameter raw water line.