Constructed in 1968 for flood control and recreational use, the Fox Creek Watershed Multipurpose Structure No. 4 dam was designed as a significant (Class B) hazard structure. As originally constructed, it consisted of an earthen embankment, a reinforced concrete pipe and riser principal spillyway, and an earthen auxiliary spillway in the dam’s left abutment. Following the reclassification of the dam as a high (Class C) hazard structure, Schnabel was retained to develop a rehabilitation design to bring it into compliance with NRCS standards.

Schnabel completed a dam break and alternatives analysis to confirm the structure’s hazard classification and develop alternatives to address its inadequate spillway capacity. To meet performance requirements consistent with the hazard classification, the Schnabel team prepared a design that included a 300-foot-wide roller compacted concrete (RCC) overtopping spillway with reinforced concrete sidewalls and a concrete ogee weir. The rehabilitation design was completed in nine months and construction was completed on schedule, even though 90 inches of rain fell at the site in the first nine months. This project represents the first case history in Kentucky where RCC overtopping protection was used for the rehabilitation of a dam.