Identifying sediment compartment dynamics on the Illawarra Coast

This project aims to produce a framework for assessing compartment dynamics

within two sediment compartments in the Illawarra region to assist in assessing

coastal hazards. Sediment sources, pathways and sinks will be examined for the

Wollongong and Illawarra Coast – South compartments, defined by Geoscience

Australia and CoastAdapt. A compartment based approach allows for more

holistic coastal planning and management which considers sediment transport at

differing scales, and interconnectivity of beaches. This type of approach

underpins national guidance on open coast risk assessment and has been

incorporated within the NSW Coastal Reforms and the Draft Coastal

Management Manual.

The adjacent sectors of the Wollongong Coast and Illawarra Coast-South

compartments extend for approximately 30 km from Bellambi Point to Bass Point.

The rock platform of Red Point marks the shoreline division between these two

contrasting compartments. The Wollongong Coast is an urbanized relatively little

studied leaky compartment, whereas the Illawarra Coast-South is a well-defined

and confined compartment whose main sedimentary characteristics are

represented by the infilling of the Lake Illawarra barrier estuary and the erosionprone

Warilla Beach.

This detailed examination of sediment resources brings together the state-wide

coastal seabed mapping program being undertaken by the NSW Office of

Environment and Heritage (OEH), and coastal geomorphological investigations

being undertaken along the southern NSW coast by the University of Wollongong

(UOW). These initiatives involve collation of historical data, sediment sampling,

and the use of recently available sophisticated remote sensing technologies,

such as terrestrial airborne LiDAR, single and multibeam bathymetry, sidescan

sonar imagery, and underwater video and still camera.