The Floodplain Management Plan divides the Cockrone Lagoon area into six precincts:

• Cockrone Lagoon - Beach Berm High Hazard Floodway/Investigation
• Cockrone Lagoon - Entrance Area High Hazard – Low Hazard Floodway/Investigation
• Cockrone Lagoon - Storage Area Low Hazard Flood storage
• Cockrone Lagoon - Floodway Area High Hazard Floodway
• Merchants Creek - Floodway Area High Hazard Floodway
• Newell Road Floodway High Hazard Floodway

These precincts have been classified for flood hazard as: High Hazard - Floodways - Cockrone Lagoon beach berm; - Cockrone Gully, from the upstream study boundary to its confluence with Cockrone Lagoon (identified as Cockrone Lagoon floodway); - Merchants Creek floodway from the confluence of Merchants Creek with Cockrone Lagoon to the upstream study extent; and - an existing open drain through the residential areas bounded by Newell Road and Three Points Avenue. High Hazard – Low Hazard Floodway (Floodway Investigation area) - Cockrone Lagoon at its entrance to the ocean (Floodway/Investigation Area); Low Hazard - Flood Storage - Cockrone Lagoon and foreshores excepting high hazard areas above. These precincts are illustrated on Figures 2 and 3, while Figure 4 provides greater detail in the Cockrone Lagoon Entrance Area. Council has adopted a policy of opening the lagoons when water level reaches RL 2.53 m AHD (identified as the let-out-level). Council has, in the past, also adopted a policy that requires new buildings to have floor levels above RL 4.3 m AHD. These two policies effectively constitute Council's current floodplain management practice around Cockrone Lagoon.