The twin towns of Forster and Tuncurry are situated at the mouth of Wallis Lake on the mid-north coast of New South Wales, about 120 km north of Newcastle. The towns form an important urban centre which has experienced rapid growth in recent years. Forster and Tuncurry have experienced flooding from Wallis Lake in the past. The highest recorded flood level was 2.25m AHD in April 1927 at Point Road, Tuncurry, just upstream of the bridge over the lake.

It is estimated that under existing development conditions, about 1300 houses would be on flood liable land in the 1% AEP flood event, of which about 1000 houses would be inundated above floor level. However, most of the flood liable properties would be in low hazard areas where flow velocities are low and evacuation could be undertaken without undue risk as the floodwaters rise. The locations which are provisionally considered to be high hazard. in the 1% AEP flood are low lying areas near Beach Street and Wharf Street, and near Point Road and Bay Street, Tuncurry. Great Lakes Council has adopted the 1% AEP flood as the designated flood for the study area. This flood standard was used for the analysis of flood mitigation and development options.