Scour measurements at contracted highway crossings in Minnesota, 1997

During record flooding in the Minnesota River basin in April 1997, the U.S. Geological Survey, in cooperation with the Federal Highway Administration, collected real-time scour measurements at contracted bridge openings and provided data collection assistance to the Minnesota Department of Transportation bridge inspectors. Weather and flood plain vegetation restricted data collection to what could be collected from the bridge deck at many sites. The data collected from the bridge deck provided only a marginal description of the reference surface for contraction scour and of the flow distribution in the stream and flood plains upstream from the bridge. However, the measurements reflect the contributions of both local and contraction scour, thus providing the streambed geometry resulting from the total scour.