Cockle Creek drains a 106 km2 catchment to the northern end of Lake Macquarie at Boolaroo (refer Figure 1). The stream is tidal upstream to the weir located near Northville. It is fed by a number of tributaries including Burkes, Flaggy, Cocked Hat, Brush, Winding and Argenton Creeks. The floodplain of Cockle Creek and its tributaries extends through the suburbs of Barnsley, Boolaroo, Edgeworth and Glendale, downstream to the northern end of Lake Macquarie near Speers Point. The susceptibility of the floodplain areas of all of these tributaries to flooding is well recognised. Flooding along Cockle Creek has occurred on many occasions with the most recent widespread flooding occurring in February 1981. During that flood approximately 35 residential properties in the catchment were damaged by floodwaters. In recognition of the considerable flood hazard, Lake Macquarie City Council is developing a floodplain management strategy for the lower Cockle Creek floodplain. The aim of the strategy is to reduce flood impacts in potentially flood affected areas, and to provide planning controls for development. It will also ensure contingency planning and evacuation measures are in place for any future flood. A number of flood related investigations have been undertaken over the last 15 years to find solutions for existing flood problems and to avoid additional problems created by proposed development in the catchment. These have included:

• the ‘Cockle Creek Flood Study’ (1986), which aimed to identify the nature and extent of the flood hazard within the Cockle Creek floodplain under existing catchment conditions;
• the ‘Winding Creek Flood Mitigation Study’ (1992) and associated ‘HEC-2 Flood Level Estimation of Winding Creek’ (1994); and,
• the ‘Cockle Creek Floodplain Management Study’ (1993), which aimed to assess proposed flood mitigation and development options in the lower reaches of the Cockle Creek floodplain.