Moderately hazardous: 4-6
Highly hazardous: 7-8
Extremely hazardous: 9-10
Busselton Beach (WA 749) is the longest continuous section of this part of the bay shore. It commences at the Siesta Park groyne and gently curves to the east for 15.3 km past the long Busselton jetty to the rock groynes of the Port Geographe development.
The beach along this section is a relative continuous crenulate beach, broken only by human structures, including the Buayanyup and New river drains and the 2 km long Busselton jetty, the longest in Australia. The length of the jetty is an indication of the extensive shallow sand flats, including sand waves and seagrass meadows that line the southern shores of the bay.
The sand waves slowly migrate eastward along the bay, causing the adjacent shoreline to oscillate. Unfortunately structures and roads were built unwittingly in this zone of natural oscillation resulting in the need for seawalls and groynes to protect the road and property along parts of the beach.
Most of the beach is backed by a wide foreshore reserve. It contains a bike path, and either side of the jetty numerous amenities, including an oceanarium and entertainment centre at the jetty, as well as boat ramps and sporting facilities.
The beach along the Busselton shoreline lies in the apex of north-facing Geographe Bay and initially faces northwest, then north and finally northeast against the eastern groyne. Owing to protection from Cape Naturaliste, it generally receives no to very low swell and only small local wind waves during northerly wind conditions. These result in a moderately steep narrow beach, fronted by the extensive sand flats and sand waves, with boats often moored off the beach. Seagrass is commonly washed up onto the beach, and at the far eastern end of the beach is causing major problems as it piles up against the Port Geographe groyne.
This is a relatively safe beach under normal conditions. A tidal swimming enclosure is located just west of the jetty, otherwise people swim all along the beach.
Port Geographe is a marina and canal estate development, constructed between 1995 to 2003, on the Wonnerup wetland and beach area 5 km east of Busselton. In developing the canal estate the wetlands were dredged, and to connect the canals with Geographe Bay, a drainage-navigation canal and entrance training walls, and associated groynes were built. The structures cross a once continuous beach and include two training walls, two inner secondary walls and two downdrift groynes. Between the six shore perpendicular rock structures are four new beaches (WA 750-753) (Fig. 4.154), while the original beach is broken into beaches WA 749 and 754. The construction of such a structure has had a number of predictable impacts on a shoreline experiencing west to east longshore sand transport and with extensive seagrass meadows offshore. First and most obvious is the trapping of the seagrass debris against the updrift wall, along the eastern few hundred meters of beach WA 749, within the entrance canal on beaches WA 750 and 751, and towards the eastern ends of beaches WA 752 and 753. Second, has been the accumulation of sand on the same updrift side of the groynes and training walls causing the beach to build out tens of metres. Third, has been the starvation of sand from the downdrift Wonnerup Beach (WA 754) which is has lead to erosion of the beach back to the main Layman Road. As a result the council constructed first one, then a second rock wall to protect the road, and replace the former sandy beach and foredune . The four ‘beaches’ have all be artificially formed through the construction of the boundary groynes and training walls, then filled with sand. They may take some years to fully adjust to a more equilibrium states. The following description is based on site inspections undertaken in August 2001.