The Narrabeen Lagoon entrance periodically fills with sand transported from storm tide events and trapped by the lagoon. This causes increased flood risk for built and recreational infrastructure during heavy rainfall and king tides, as water cannot escape the estuary rapidly. Sand is periodically removed from the lagoon entrance and placed on the nextdoor Narrabeen and Collaroy beaches, which are experiencing substantial erosion pressures. This project successfully addresses the flood risk at the lagoon, but the renourishment is not enough to address the ongoing erosion at the beaches.

Beach renourishment

Method: Artificially nourished

Sand source: River

Sand volume (m2): 45,000

Sand placement: Visible beach

Frequency of renourishment: 3 years (2018 then 2021)

Date of last renourishment: 2021