The wider Barwon area is shown in Figure 6-6. The bluff west of the Barwon River entrance protects much of the shore east of here. Waves refract and energy dissipates as they approach the Ocean Grove shoreline, reducing wave heights. The Barwon Heads township is on the western bank of the river. The western bank is protected by a series of high vertical timber and masonry retaining walls. These protect the hinterland properties against high river and coastal flooding events. The elevations of the walls range from 1.6 m to over 3 m AHD with numerous properties lying behind. There is also a section near Ozone Road that has no formal protection; however this backs on to high ground.

Figure 6-6     Compartment 3: Barwon Heads, Barwon Estuary and Lake Connewarre

The estuary fringes are characterised by very fine muddy sediment, indicative of a low-energy environment. The Ocean Grove spit is protecting the inner reaches of the estuary from wave energy which has allowed the establishment of extensive areas of saline habitat, such as mangroves and saltmarsh. The historic imagery shows some migration of the low water channel which may have contributed to the localised bank erosion. The western bank (Barwon Heads township) is fronted by a series of mostly vertical retaining walls (Figure 6-7a). The eastern bank of the river (Ocean Grove) has erosion protection in the form of a low rock revetment (Figure 6-7b); however this will have little effect against inundation.

The Ocean Grove spit has evolved through the alternate ocean and river pressures. Waves refract around the bluff and deposit sediment in a curved spit, whilst the flowing river contributes to spit formation from the inside. In the past, the spit migrated in response to changing conditions, however now it is largely fixed in place by rock work.

Figure 6-7      (a) vertical retaining wall - western bank Barwon River (b) erosion protection - eastern bank Barwon River (Ocean Grove)