Seismic refraction techniques were used to investigate bedrock conditions at the site proposed for a dam at Wirrina Holiday Village. The extent of a landslip which occurs on the left abutment of the dam was detmined from two seismic traverses made on the left bank of Congeratinga Creek. A seismic traverse over a saddle on the hill which forms the right abutment gave information on the depth of weathered rock likely to be encountered in excavations for the spillway.