Cockrone Lagoon Flood Study

This Flood Study comprised the following principal stages:

• collection and assessment of available data;
• investigation of coastal processes to determine design ocean levels for tailwater boundary conditions for the hydraulic model and to determine ocean storm inflows into the lagoon;
• development and calibration of an hydrologic model to convert design storm rainfalls into design flood hydrographs; and
• development and calibration of an hydraulic model to determine design flood levels in the lagoon and on the floodplain.

Available data comprises:

• Council records of lagoon openings (the most comprehensive available);
• Department of Land and Water Conservation (DLWC) Rainfall data at Kincumber Sewage Treatment Plant; and
• Bureau of Meteorology Daily Rainfall Records.

The initial flood studies, outlined in this report, indicated significant sections of the Three Points Avenue area of MacMasters Beach would be flood liable. Ground survey of individual properties showed that the established model was not sufficiently refine to accurately represent the separate flow paths. An individual flood study was undertaken of the drain running parallel to Newell Road and Three Points Avenue. The study report appears as Addendum A to this document, while the results have been included on Figure 10.