Scour at bridges, what's it all about? Stream stability and scour-assessment at bridges in Pennsylvania

Scour is the removal of sediment (soil and rocks) from streambeds and streambanks caused by movingwater. Although scour may occur at any time, it is usually more significant during high flows, when the water is swift and deep. Swiftly movingwater has more energy (turbulence and velocity) to lift and transport sediment than slowly moving water.