Time to desilt dams on KI
While the dry weather continues, now is the ideal time for primary producers and landholders across Kangaroo Island to desilt dams before the rain breaks and conditions become too wet and muddy for maintenance works.
Kangaroo Island Landscape Board General Manager Will Durack said that although landholders do not need a permit to desilt dams, they must follow a set of provisions listed in the Board’s Water Control Policy.
"It is important for landholders also to be aware that dams are regularly monitored by satellite imagery to detect enlargement of dams that have not been approved, which is an offence under the Landscape Act that carries penalties," he said.
"During the process of desilting dams, landholders can only excavate the washed in loose silt. They are not permitted to enlarge the dam's size or dump silt into watercourses," he said.
Mr Durack said the best way to avoid impacting local waterways is to not place dredged silt on the spillway, filter zone or drainage lines.
Mr Durack emphasised that desilting dams is not just a necessary chore, but a proactive step that will maximise the volume of water your dam will hold, improve water quality held in the dam and potentially prevent costly structural failures.
"Owning a dam can present some challenges, one of which is the accumulation of silt within the dam," Mr Durack said.
Suspended fine sediments originating from water erosion that occurred upstream of the dam and transported within surface runoff are the source of silt accumulation in the dam.
Maintaining vegetation cover in the drainage lines will reduce water erosion and the accumulation of silt in your dam.
"Silt not only reduces the holding capacity of your dam but can also reduce the quality of water held within the dam and cause problems for pipes and pumps pulling water from your dam," Mr Durack said.
"Dams are not just a set-and-forget arrangement," he said, "They need ongoing monitoring and management to maintain their integrity and continue to serve you."
"If you need advice, please contact the Landscape Board; we are here to help you."
To learn more about the provision that must be followed when desilting a dam please see Section 2.3.2.19 of the Water Control Policyor contact the Kangaroo Island Landscape Board on (08) 8553 2476.
