FAQs

The project is initiated by Kempsey Shire Council, and is funded jointly through Council, and the NSW State Government’s Coast and Estuary Grants Program.  

The Entrance Management Plans are being developed in partnership with specialist coastal management consultants. It will involve significant engagement with the local community, user groups, and public authorities. 

ICOLLs are separated from the ocean by a sand beach barrier or berm. This entrance barrier forms and breaks down depending on the natural movement of sand in an out of the estuary by waves, tides, flood flows and winds. 

Generally speaking, coastal process such as tides and waves tend to push sand into the entrance, while freshwater flows and flood waters from the catchment tend to scour the sand out. The ebb and flow of these forces means that estuaries opens and close to the ocean naturally, in a constant but irregular cycle. 

This balance between open and closed states varies for every estuary. Some ICOLLs are nearly constantly open to the ocean, while others can remain closed for several years at a time. 

Council is responsible for managing ICOLL entrances and undertaking artificial openings under their duty of care to the local community. The two most common objectives for artificially opening lagoon entrances are (i) to mitigate flooding, and (ii) to improve water quality. 

Entrance management plans can be developed and adopted by Councils to set out relevant rules and procedures, such as for carrying out artificial openings. 

Management of ICOLL entrances is sometimes a controversial issue in local communities with competing interests wanting entrances opened more often or less often for different reasons. Developing an entrance management plan therefore requires significant consultation with the local community and a range of public authorities. 

Artificial breaching of ICOLL entrance barriers has been undertaken in many places in NSW in order to alleviate flooding caused by rising ICOLL water levels. Opening up the barrier will cause water to flow from the estuary into the ocean, and can relieve flooding along the ICOLL’s foreshore. While this breaching will occur naturally over time, flooding of low-lying foreshore developments may trigger calls to artificially open an ICOLL before it naturally opens.  

While artificial opening may reduce foreshore flooding, the artificial lowering of water levels can cause the death of aquatic vegetation, leading to deoxygenation of the estuary’s water (i.e. blackwater events), which can suffocate fish and result in extensive fish kills.  

If an ICOLL is occasionally artificially opened within its natural breakout range (i.e. within the range of water levels a natural breakout would occur) there is unlikely to be any significant environmental impact. However, continual and long-term entrance opening can lead to major environmental shifts of the ICOLL ecosystems.