ENGINEERED TO NATURAL: CHRONICLING THE CHANGES OF THE SAND SPRING RUN STREAM, 1976-2013

The Sand Spring Run stream (SSR) is located in is a small drainage basin (1522 ha) in the Allegheny Mountains of western Maryland in the west central watershed of the Chesapeake Bay. The SSR flows across the campus of Frostburg State University (FSU) and the channel was relocated in 1976 c. 200m to the SW for the construction of a football field. Following the relocation it was again modified in 1995 by FSU via channel straightening. The engineering changed the SSR from a natural sinuous channel Rosgen class C to one that closely resembles a Rosgen class Aa+ channel, but with a low slope range (<2%) and with an apparent initial uniformed channel depth (no numeric data available). Following the last phase of channel straightening the SSR has begun to revert back to a “natural” sinuous state by progressive erosion of its narrow floodplain regulating its transport capacity and efficiency. In addition non-uniformed bed erosion has occurred along the engineered section leading to differential removal and deposition of a wide range of sediment sizes, prompting phases of channel readjustment to seasonal inputs (winter melt) and high magnitude but low frequency precipitation events. In 2013 a channel morphology-monitoring program was instigated, to allow comparison of contemporary channel characteristics with historic records obtained from aerial photographs, with the goal of modeling and predicting future channel modification.