This study consisted of a hydrographic survey and determined maximum scour around the piers at eighteen selected bridges on the Cimarron, Arkansas, and Caney Rivers. The survey was performed soon after the 50- to I00-year-frequency flood in October, 1986. It was determined from the survey that maximum scour varied from 0.60 to 18 feet with depth of flow ranging between 0.75 to 25 feet. The October, 1986 flood of the Cimarron River resulted in severe scour around piers of eight overflow structures of the 1-35 bridge. A major portion of the flood passed through these structures, resulting in a high velocity of flow. After the flood receded, the maximum depth of scour ranged from 10 feet to 30 feet. At U.S. 75 on the Caney River, a hydraulic analysis of water surface profiles using WSPRO program was determined for 50-, 100-year, and the 1986 flood because of the old bridge and new bridge. Because design criteria for scour depths at piers are based mostly on laboratory work and because some bridges designed according to these criteria have failed, it is recommended that this study be extended to collect field data on the maximum scour at selected bridges over a four-year period. Field data will be collected four times a year for various high and low flow conditions. Laboratory and field data are to be analyzed and used to produce design criteria so that damages to bridge piers are minimized. Further laboratory and field data will be generated for different river-bed soils (sand, silt and clay) and for varying hydraulic conditions.