2021-10-08 SM - Item 1 - Attachment 2 - Draft Coastal Hazards Adaptation Plan - tracked changes

MARCUS BEACH AND CASTAWAYS BEACH
Setting
Marcus Beach and Castaways Beach are localities set in undulating coastal dunes and vegetation.
They are located midway along what is locally known as the ‘Eastern Beaches’. Both localities
each have beachfront totalling approximately two kilometres in length. Protected by vegetated
dune buffers, both localities predominately provide housing for permanent residents, with some
short-term visitor accommodation, and commercial or retail uses. Two coastal creeks, Marcus
Creek, Castaways Creek, and Burgess Creek flow through the coastal dunes to the beach and out
to sea. David Low Way represents the primary means of entering and exiting these localities from
the South and the North. For much of this area, David Low Way is situated between residential
areas and the dune zone and beachfront.

Risks to Marcus Beach and Castaways Beach
The beachfront in this area has historically experienced some short term erosion along the beach
and frontal dunes after large swells and tropical cyclones, with recovery occurring through natural
coastal processes gradually over time. Appendix 4 shows the projected change in the erosion
prone area due to sea level rise across various parts of Marcus Beach and Castaways Beach
during a severe storm event. Appendix 4 shows the change in risk profile across various parts of
Marcus Beach and Castaways Beach as the area exposed to the effects of coastal erosion
increases. Table 6 provides a summary of the changing risk profile for six broad asset types within
the locality that are projected to be exposed to the effects of coastal erosion between present day
and 2100.

Due to the ongoing presence of wide vegetated dune systems in this locality, much of the risk from
erosion is only likely to affect natural assets, with some potential for risks to David Low Way and
the parking area at Castaways Beach expected toward the end of the century. Damage to David
Low Way in this locality could present an accessibility hazard to the community in Castaways
Beach, as this road provides the only access to this suburb from the north and south. Costs
associated with repairing this damage would be significant and involve lengthy construction times.


          Asset Type                                 Erosion Risks by Year
                               Present Day            2040          2070                     2100
          Tourism                                            Low
          Business                                               Low
          Residential                                            Low
                          11
          Infrastructure            Low              Medium               High            Very High
          Recreational                                 Low                                 Medium
          Natural                            Low                                  Medium
         Table 6 - Change in Marcus Beach and Castaways Beach asset risk profiles across planning horizons


At present, the only methods for mitigating coastal erosion risks in Marcus Beach and Castaways
Beach are:

    -   Maintaining and enhancing vegetated dune areas, which act as a natural buffer to erosion
        by dispersing wave energy during storm events
    -   Planning controls on coastal development that prevent encroachment into the vegetated
        dune areas, thereby preserving natural coastal processes of erosion and accretion.

11 Some buried infrastructure is at risk, however the primary infrastructure concern in this locality is David

Low Way
Noosa Council – Coastal Hazards Adaptation Plan 2020 - 2030                                                  Page 40