Rapid Assessment of Channel Stability in Vicinity of Road Crossing

The ability to assess channel stability of gravel bed rivers in the vicinity of structures such as bridges, culverts, and roadways is necessary for bridge inspection, design, and the mitigation and prediction of erosion at those structures. Given the time constraints for bridge inspections and the expense of conducting lengthy geomorphic studies, it is desirable to have a technique for rapid assessment. Although several methods are currently available for the rapid and qualitative assessment of stability, these methods are often vague or apply only to a specific region. In this paper, we review existing methods and parameters for assessing channel stability and develop a systematic rapid channel stability assessment method based on various aspects of the existing methods. The rapid assessment method provided here is based on 13 qualitative and quantitative indicators of morphologic processes. The indicators are rated, weighted, and summed to produce a stability rating for gravel bed channels. The method is demonstrated through application to several streams in Pennsylvania and Maryland.