The health of our waterways is also impacted significantly by the amount of surface water that flows into them. Changing climatic conditions means that even without any human influence, this “natural” runoff is decreasing. The chart below showing a 30%+ decrease from the Upper Barwon Catchment into Barwon Water’s storage, which is used to supply the City of Greater Geelong.
As the river flows from this site in the Otways to Geelong, water is “harvested” by local communities and individuals for their own use, whether it is for irrigation of crops or gardens or for domestic stock.
Water also finds its way to the river as runoff from the surrounding catchment, but as the number of landholders increases across the catchment, more and more of this water is being trapped in dams and tanks.
The Barrabool Hills Landcare Group has run a number of programs to support landholders to make more efficient use of water on their properties. These include:-
- Managing stocking rate so that water is able to penetrate the soil and stay in the landscape longer
- Supporting projects which provide incentives to pump water into off stream tanks
- Efficient harvesting of water from roof areas
- Construction of dams which have smaller surface area and which are fenced to maintain water quality. Unfenced dams result in contamination from animal faeces and silting from the surrounding exposed banks as seen in extreme example below.
As an alternative dams can be fenced off and evaporation minimised by adding banks of native vegetation, including grasses to minimise soil contamination of the water. See below a suggested plan.
Other programs include: