Whitewood Creek Reclamation Plan: A Sound Basis for Design

A reclamation plan was developed for an approximately 1,100-meter-long, placer-mined reach of Whitewood Creek near Deadwood, South Dakota. The objectives of the design were to provide a geomorphically stable system that will require minimal maintenance, maintain water quality in the creek, and enhance the habitat-limited trout fishery. The objectives of the project were met by designing an integrated landscape in which both the valley floor and channel of Whitewood Creek function to pass a range of flows and their sediment loads, while maintaining the reach in a dynamically stable condition. This was accomplished by providing a two-stage channel that maintains reasonable velocities and depths at low flow, but allows the flow energy to dissipate at higher, flood flows by spreading over a wider area. Vertical stability was achieved with boulder-step structures that also enhanced instream habitat by providing chutes and pools that remain largely clean of fine sediment, even at lower flows. Lateral stability was provided with a combination of boulder edge lining, where site conditions dictate that lateral migration cannot be tolerated, and a series of buried rock spurs in the overbanks where some lateral migration can be tolerated. Principles of hydraulic engineering and engineering geomorphology provided a sound basis of design for the project. In spite of at least two flood flows since completion of the project in 1996, the design has proven to be successful in stabilizing the channel, while significantly improving the fishery and riparian habitat conditions within the reach. Damage that occurred during the recent floods was primarily related to overbank erosion that occurred in areas where the revegetation had not had sufficient time to become fully established.