Twenty bridge sites in Indiana were evaluated to determine: the extent of scour during floods, streambed stability, the maximum historical scour, and estimates of potential scour. Historical scour data were collected by means of geophysical methods and used to evaluate the scour-computation procedures recommended by the U.S. Federal Highway Administration and 13 other published pier-scour equations. Hydraulic conditions for the peak historical discharges were estimated by use of WSPRO, a water-surface profile computation model. Depth soundings were made periodically at all of the sites and during flooding at some sites. These data indicate that scour may not totally be a function of discharge or depth but is influenced greatly by debris on piers.