|Riverbank between Pollocksford and Merrawarp Roads|
Bedload can build up on the stream bed further upstream, restricting the flow of water and movement of fish and other river fauna as well as adversely impacting on their habitat.
Prior to European settlement, the river environment was believed to be relatively stable, however from 1836 onwards, clearing of native vegetation, the introduction of stock which impacted soil quality and bank stability and the exploding rabbit population burrowing into banks all added to a rapid increase in erosion along the Barwon. Other contributing factors included the draining of wetlands and marshes for farming purposes and the diversion of water from the Barwon and its tributaries.
|The West Barwon Dam|
Another introduced species which can impact riverbank stability is the introduced carp, which not only eats the plants necessary for the survival of native fish, but with its aggressive feeding habits can cause bank erosion. Various initiatives such as "Catch-a-Carp Day" and the draining and dredging of Reedy Lake where a tonne of carp was removed help to control levels of this pervasive pest. If caught while fishing, it is illegal to return carp to the river.
|A carp grazing along the riverbank at Marshall|
In some cases, natural events also contributed to the problems. When a landslide blocked the channel of the East Barwon River in 1952 causing the creation of Lake Elizabeth, water flow was significantly impacted. The following year when the blockage was partly breached, soil and debris was washed downstream, covering lower-lying farmland. Major flooding in 1995 also caused significant erosion.
|Aerial view of the 1995 floods looking south west from the Geelong Advertiser|
Today, ongoing measures to minimise erosion and improve water quality are in place and a multitude of Landcare groups across the region work in conjunction with the Corangamite Catchment Management Authority to rehabilitate the Barwon.
Bank and gully erosion can be reasonably effectively controlled in rural areas by restricting the access of stock to rivers, creeks and gullies and by revegetation along riverbanks and areas likely to suffer from erosion. Education of landholders and improved farming methods are also important.
Hillslope erosion is best controlled by encouraging good ground cover improved soil structure which can be aided by measures such as the retention of stubble from cereal crops and the use of raised-bed farming.
|Sheep on the river between Pollocksford and Merrawarp Roads|
|Bank stabilising near Barwon Valley Golf Course|