Farmers in south-west Victoria may be considering cleaning out sediment from their dams after a dry autumn season.
However, Agriculture Victoria Land Management Extension Officer Clem Sturmfels, is encouraging famers to think carefully before proceeding.
'Cleaning out dams at this time of the year can be difficult, dangerous and expensive. Handling wet dam sediment requires specialised equipment.
'Using a bulldozer to remove this sediment is slow and tedious work and excavators usually don't have the reach to do this work efficiently,' said Mr Sturmfels.
Dams with fresh deposits of soil, manure, and other organic matter are more likely to grow algae and bacteria. Allowing these deposits to dry out over summer allows the material to be removed using a scraper or bulldozer.
'It's important to closely monitor the dams while waiting for them to dry out to avoid any animal health issues.
'Dams with older sediment are less likely to have water quality concerns and a metre or so of sediment will have little impact on dam capacity.
'Assessing the depth of sediment in a dam can be difficult. Farmers can make an estimate by measuring the depth of the dam and comparing that to the dam's dimensions.'
A depth sounder or Damdeep measuring device can be used. A video of making and using Damdeep can be viewed here.
Farmers are encouraged to consider the following when undertaking dam cleaning activities:
- the sides of dams can be slippery and pose a risk to humans, stock and plant operators
- dam sediment should be placed in a location where it cannot re-enter the dam or other waterways
- steepening the sides of the dam can result in erosion and further sedimentation
- avoid any works which impact the structural integrity of the dam or associated outlet devices.
It's recommended to contact the local rural water authority in your area prior to commencing sediment removal works, as a permit may be required.
Details of rural water authorities can be found here.
