The study area defined by Council is as follows:

• The Nepean River from Menangle Weir (4.5 kilometres upstream of Camden Council’s LGA boundary) to the river’s confluence with the Warragamba River near Warragamba Park; and
• Five tributaries of the Nepean River within Camden Council’s LGA boundary, namely Navigation Creek, Matahil Creek, Sickles Creek, Cobbitty Creek and Bringelly Creek.

The general approach and methodology employed to achieve the study objectives involved:

• Compilation and review of available information, including previously completed flood studies, streamflow gauge records, rainfall records, topographic mapping of the floodplain and details of bridge crossings and other structures;
• Site inspections and interrogation of aerial photography and other geographical data in order to establish catchment roughness, slope and land-use attributes;
• The collection of historical flood information, including records of peak flood levels for historical floods;
• The development of a computer based hydrologic model to simulate the transfer of rainfall into runoff and its concentration in local streams during flood events;
• The development of a computer based hydrodynamic model to simulate the movement of floodwaters through the reaches of the Nepean River floodplain that lie both within and downstream of the boundaries of the Camden Shire Council LGA area;
• Calibration and verification of the models; and
• The determination of peak flood levels and flow velocities at selected locations along the selected reach of the Nepean River for the predicted 500, 200, 100, 50, 20, 10, 5 and 2 year Average Recurrence Interval (ARI) floods and the Probable Maximum Flood (PMF).