We are responsible for the management and maintenance of the surrounding foreshore reserves and nearby beaches of Lake Cathie. The estuarine system on both the west and east sides of the Kenwood Bridge are owned and managed by the NSW State government.
Our role in dredging Lake Cathie is to provide recreational amenity to the community and respond to coastal erosion hazards along Illaroo Road. In order to undertake such work, we must request permission from the state to do so. Due to the ongoing nature of these works Council has identified periodic maintenance dredging as a suitable means to remove accumulated sand banks within the waterway. The Dredging Strategy (2007) proposes ongoing dredging every 5-10 years. The Lake Cathie Coastal Zone Management Plan (2016) identifies excess dredged sand to be placed on Lighthouse Beach to act as a mitigation measure for predicted long term coastal recession. We have modified our Development Application (DA) which allows dredging in 2021 to add a coastal hazard based trigger. This allows us the opportunity to dredge the lake more frequently if certain environmental conditions are met. Dredged spoil is placed on Lighthouse Beach adjacent to Illaroo Road and creates a sand buffer from coastal erosion impacts.
In the years following dredging, sand accumulates into the lower estuary and can impact on the amenity of the recreational activities generally undertaken in the lower waterway. The sand buffer on Lighthouse Beach is typically also lost during this time due to the erosional nature of the beach environment.
This work is typically undertaken with a ‘suction/cutter' dredge. The beach nourishment work involves placement of dredged sand in front of the properties along Illaroo road to form an artificial dune. The placement of this sand is typically undertaken by an excavator with the sand being pumped to the beach via a pipe from the dredge.