Scour of riverbeds at bridge abutments has been a problem for many years. Excessive scour can cause abutment damage and potential loss of life due to bridge collapse. Various countermeasures have been investigated and used with varying degrees of success. Countermeasures can be described in two categories: "bank- and bed-hardening" and "flow-altering". Among bank- and bed-hardening countermeasures are riprap, cable-tied blocks, Toskanes and similar interlocking devices, and soil cement. Flow-altering countermeasures include vanes, guide banks, and spur dikes of various configurations. These countermeasures either reduce local scour at the abutment or attempt to maintain the channel alignment so that the channel does not outflank the bridge. However, several practical considerations limit the viability of most countermeasures. The considerations include washout of bank-hardening elements, winnowing of the fines between bank-hardening elements, and scour outside the lateral domain of the bank-hardening elements. Flow-altering devices can be outflanked, can be ineffective when flow direction is altered, may wash out themselves, and can snag debris or ice. A three-year research project is underway by the authors and sponsored by the National Cooperative Highway Research Program of the Transportation Research Board to define which countermeasures merit further study and to develop design guidelines for those countermeasures.