Oxley Island – Polsons, NSW

Rock fillets are constructed adjacent to eroding estuary banks for stabilisation. Rock fillets are energy dissipating structures, which are typically built to mean high water level from locally quarried rock, although fillets may also contain other habitat enhancement structures such as timber snags, or prefabricated reef balls. The fillets are a bank parallel structure, keyed into the bank at one end and open at the other, creating an area of low hydrodynamic energy in the intertidal zone between the fillet and the bank. This area of still water encourages sediment accumulation, and the regeneration of mangroves and other estuarine vegetation, where the mangrove propagules, fish and other estuarine fauna can pass through the fillet opening.

Project details

Mangroves

Method: Hybrid, Rehabilitation

Rehabilitation - method: Grazer control

Mangrove species: Avicennia marina

Hybrid structure: Rock fillet

Hybrid structure height (m): 1.5m

Hybrid structure width (m): 2.5m

Hybrid structure length (m): 25-60m

General information

Approach

Mangroves

Geographic context

Estuary

Primary objective

Coastal protection

Coastal hazard

Erosion

Asset vulnerable

Natural

Length of coastline targeted (m)

415

Date of completion

2016

Cost ($AUD)

$60,000