This Flood Study was carried out for Lake Macquarie City Council, to define the nature and extent of the flood hazard under existing catchment conditions. The Study area encompasses Dora Creek and its two main tributaries up to their tidal limits. Flood levels have been determined downstream of the weir below the Freemans Drive bridge (Cooranbong) on Dora Creek, downstream of the Newport Road Bridge (Avondale) on Jigadee Creek, and downstream of the Cooranbong Road bridge on Stockton Creek. Although the catchment has a history of flooding, reliable long term streamflow records are not available. In the absence or such records, design discharges for the 5%, 2% and 1% probability per annum floods were derived using the Cordery-Webb synthetic unit-hydrograph method. Flood behaviour throughout the study area was determined using the "SAK>D" mathematical hydraulic model. SAMOD is an unsteady state, quasi 2-dimensional cell type model which enables floodplain storage effects, off-channel storage areas and flow through specially designed floodways