Vermont Bridge Scour Rating Analysis: Looking Toward Utilizing Geomorphic Stream Data

Scour is the leading cause of bridge failure throughout the United States and elsewhere. Reliable scour ratings and methods for estimating the potential for scour can be effective tools in predicting and mitigating scour damage to bridges. The Vermont Agency of Transportation (VTrans) rates every bridge in the state for susceptibility to scour-type failure following the Federal Highway Administration's National Bridge Inventory guidelines. The scour rating is largely bridge and site specific and currently does not account for larger-scale stream geomorphic characteristics. In a complementary effort, the Vermont Agency of Natural Resources (VTANR) performs detailed geomorphic assessments of streams and rivers; more than 2,000 stream miles have already been assessed. This additional stream geomorphic data could prove to be useful in the scour assessment of bridges. This paper uses VTANR's geomorphic observations made around bridges and VTrans' scour ratings to explore preliminary correlations for assessment of scour potential of Vermont bridges.