American Society of Civil Engineers

Anomalous Contraction Scour? Vertical-Contraction Case

by E. M. Hahn, (Engineer, RJH Consultants, Inc., Englewood, CO 80112.) and D. A. Lyn, (corresponding author), A.M.ASCE, (Professor, School of Civil Engineering, Purdue Univ., W. Lafayette, IN 47907 E-mail:

Journal of Hydraulic Engineering, Vol. 136, No. 2, February 2010, pp. 137-141, (doi:

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Document type: Technical Note
Abstract: Clear-water scour due to a short vertical (pressure flow) contraction was investigated in a laboratory channel. Two approach velocities were studied for a (nominally) single configuration of depth and degree of contraction, with experiments conducted for various durations up to a maximum of 48 h, and the evolution of the scour hole over time monitored. The location of maximum scour in both cases was observed to occur downstream of the contraction, with maximum scour depths substantially in excess of values predicted by published models, even though equilibrium scour conditions were not reached.

ASCE Subject Headings:
Laboratory tests