Dam Modification Spawning New Whitewater Park on the Catawba River
S2O Design & Engineering heads Great Falls-Dearborn Diversion Bypass Project, design solution will open the Catawba’s Long Bypass Reach for boating for the first time in over 100 years.
In Chester County, S.C. near the North and South Carolina border—an hour’s drive south of the U.S. National Whitewater Center in Charlotte, NC—an engineering project is taking shape that will similarly attract paddlers and river enthusiasts throughout the region.
More than 100 years ago, the Great Falls-Dearborn Diversion Dam was built on the Catawba River for a hydroelectric plant, which created the Great Falls Dearborn Reservoir but also de-watered the 2.25-mile Long Bypass Reach below the dam. As part of the recent Catawba River Agreement and FERC re-licensing of the Catawba River for hydropower, a multi-million-dollar effort was launched to return water to the river for new recreational opportunities and to restore aquatic life and lowland habitat downstream of the dam.
S2O Design & Engineering, the world’s premier river engineering and whitewater design company, was tapped to devise a solution to allow flows through the diversion dam in a controlled manner and to provide safe bypass for paddlers who wish to traverse past the Diversion Dam into the beautiful corridor of class II-III whitewater. With construction past the half-way point, both water and boaters will soon be flowing down the Long Reach of the Catawba for the first time since 1907, bringing life and voice back to the rolling granite waves that are the historic “Great Falls” of South Carolina.
“This was an innovative approach to a complex challenge, and our team, including the project Owner and HDR Engineering, has done an outstanding job of navigating the engineering, construction, environmental, and regulatory variables with this project,” said Scott Shipley, S2O Design president and former kayak Olympian. “The results will bring a positive impact to the health and vitality of the river and create exciting recreation opportunities for paddlers across the region.”
S2O Design’s solution to accomplish the multiple objectives features the creation of two release points or notches in the dam for recreational release flows and boaters to navigate into the Long Bypass Reach — a Main Channel that will convey water continuously into the reach, and a Recreation Bypass Channel that will provide a safe route for boaters during recreational releases.
The 400’ long Main Channel will take most of the flow down the eight feet of drop from the reservoir to the bottom pool, providing continuous connectivity between the reservoir and the river. To accommodate these flows, the design incorporates three innovative multi-stage drop structures that help control flows through the channel at various levels without creating dangerous recirculating hydraulics common in lowhead dams.
To provide the safest possible passage to the Long Bypass Reach at higher flows, S2O Design created the Recreation Bypass Channel that will have much less drop over a longer distance. This 1,075’ long passage features nine drop structures to control the rate and intensity of flows in the channel, a recovery pool and island with gradually sloped sides, and portage trails for boaters to exit the channel if needed. S2O Design also devised innovative applications in the Bypass Channel to prevent fish from being trapped at lower flows.
In creating this solution, S2O Design engineers and hydrologists completed conceptual designs, 1D and 2D computer modeling, construction documents, and construction visualization renderings. Working with engineers at the Czech Technical University in Prague, S2O Design also created a 1:20 scale physical model of both channels to study a range of flow conditions, and fine tune and validate that the design will meet the project’s stringent design and performance parameters.
S2O Design also commends American Whitewater, who represented paddling interests across the basin during the FERC relicensing process and was responsible for spearheading the effort to open up this reach of the Catawba River to boating. These and other enhancements are part of ongoing efforts by the local utility to further open local lakes and rivers to recreational use.
Construction on the Great Falls-Dearborn Diversion Bypass began in the spring of 2021 and is expected to be completed by fall 2022.
About S2O Design & Engineering
S2O Design is an engineering firm specializing in innovative river engineering, restoration, and community-focused whitewater park design. Our team of expert boater-engineers has planned, conceived, designed, and created some of the best in-stream whitewater parks as well as largest and most dynamic recirculating whitewater parks in the world. S2O Design is led by engineer, Olympian, and three-time World Cup Kayak Champion and Freestyle Kayak Champion Scott Shipley. For more information, visit S2ODesign.com.