Shoreline erosion issues are not unique to Sydney and it has long been held that beach nourishment is, in many cases, the best long-term management strategy. If sufficient sand deposits are available for nourishment works, hazards associated with storm events and sea-level rise can be alleviated.

The primary purpose of this scoping study was to develop the outline of a sand nourishment programme utilising suitable offshore sand deposits for amenity enhancement and to ameliorate increased hazard risk from sea-level rise. A key environmental driver for the study was the projected climate change sea-level rise. Generally, sea-level rise causes beach erosion and recession which could result in permanent loss of beach amenity. The scoping study identified potential benefits and impacts of a nourishment programme associated with physical, environmental, social and economic issues. It also drew comparisons with the “do nothing” approach.

While the study scoped a nourishment programme for the whole of Sydney that is closely aligned to nourishment of all NSW ocean beaches, it case studied three Sydney beaches in more detail. The nominated beaches were Collaroy-Narrabeen, Manly and Bate Bay.
The environmental, economic and social evaluations of the nourishment campaign demonstrated substantial positive benefits associated with the project. Some potential adverse ecological impacts may be caused by the nourishment programme with the smothering of aqueous benthic communities. These are likely to be less severe than the ecological impacts associated with a “do nothing” approach and the subsequent loss of the inter-tidal beach, resulting in a total loss of the beach ecosystem.

Nourishment campaigns are scheduled at intervals of approximately 10 years, with the first nourishment campaign estimated to cost $300M at a unit rate of approximately $25/m3 of sand. The second and subsequent nourishment campaigns are estimated to cost $120M at a unit rate of $30/m3 of sand.