Fishery Beach (Bremer Bay) boat ramp protection
DoT coastal management investigations into erosion and options for stabilising Fishery Beach determined a groyne, or groyne field, as the most suitable stabilising option.
In March, works were undertaken to recover rock from the original Bremer Bay Boat Harbour construction, from a location at which it was buried. The rock was successfully recovered with assistance from the Shire of Jerramungup and Bremer Bay Earthmoving and Civil, with a sufficient quantity available to construct the proposed boat ramp protection structure (a beach groyne).
Groyne construction works were awarded to WA Limestone following a competitive tender process. Works are forecast to commence in May and be completed prior to Winter 2017.
About the project
The construction of the Bremer Bay breakwater in 1996 caused the permanent realignment of Fishery Beach. DoT is the facility manager and responsible for the breakwater and the wharf, however the Shire of Jerramunup owns the boat ramp and carpark areas, and is the coastal manager of the area. The realignment of Fishery Beach resulted in erosion of the western end of the beach creating a steep escarpment and some loss of usable beach. Eroded sand migrates onto the boat ramp at the eastern end of the beach. This accretion of sand hinders the ramps' use, presents a possible safety risk in an emergency and leads to ongoing maintenance costs for DoT to clear the sand annually.
DoT coastal management investigations into erosion and options for stabilising Fishery Beach determined a groyne, or groyne field, as the most suitable stabilising option. The DoT secured RBFS funding in 2016/17 to attempt to design and construct the proposed groyne option, though sourcing materials to construct the groyne remained cost prohibitive. Investigations into available rock sources identified that the remnant blasted rock from the harbour construction in 1996 was disposed in an old borrow pit on private land approximately a kilometre from the boat harbour, and was able to be accessed with earth moving equipment.
The construction of a beach groyne adjacent to the Fishery Beach boat ramp with the identified rock will prevent sand migration onto the ramp and significantly improve the amount of time it can be used safely. The proposed 55 metres long groyne is close enough to existing rocks and the shore line, not to anticipate any siltation of the boat harbour basin. The groyne should secure all year round safe access to the boat ramp for recreational boaters and marine rescue activities. The groyne should significantly reduce the frequency of sand excavation exercises leading to a reduction in ongoing maintenance expenditure.
This project has been funded by the Recreational Boating Facilities Scheme (RBFS), and has been progressed with support from the Shire of Jerramungup.
|Fishery Beach, Bremer Bay, 3D Visualisation Groyne||Kb|
|Fishery Beach, Bremer Bay, photo match||Kb|