The Effects of River Ice on Scour and Sediment Transport

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Cold Regions Research and Engineering Laboratory
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.538.7648; http://cripe.civil.ualberta.ca/Downloads/13th_Workshop/Hains-Zabilansky-2005.pdf

Field observations indicate ice covers significantly affect sediment transport processes in rivers, especially scour at bridge piers. To establish the sensitivity of various parameters affecting sediment transport processes under ice, twenty tests were conducted in a refrigerated flume at the United States Army Corps of Engineers Cold Regions Research and Engineering Laboratory. All tests were conducted using a 5.08-cm-diameter circular bridge pier and sand with d50 = 0.13 mm with various discharges. Flow velocities were selected to focus primarily on clear-water scour using both smooth and rough simulated ice covers for three surface conditions: open water, floating cover where the ice was free to respond to changes in water level, and a fixed cover simulating ice frozen to the pier and banks with a hydrostatic head created by an upstream ice jam. The cover roughness and pressure flow condition both alter velocity distribution and caused live-bed scour even when the mean flow velocity, Vavg, was less than the critical velocity for bed movement, Vc. The combination of increased cover roughness and pressure flow resulted in the largest scour depth. This paper presents a summary of the field investigations and laboratory experiments, and discusses both the velocity distributions and shear stress analysis. 1.