Echunga incident a timely reminder to maintain dams
The near-collapse of a farm dam above Echunga in the Adelaide Hills recently has highlighted the importance of landholders conducting regular monitoring and maintenance of their dams.
Regular inspection and management of dams can significantly reduce the risk of them overfilling and adding pressure to dam walls, potentially causing collapse. Dam overfill and wall failure can jeopardise the safety of downstream neighbours, assets and the local environment. Routine inspection also enables the identification of minor defects which can be repaired cost effectively before major damage occurs, prolongs the life of the dam and protects it against deterioration.
Landscapes Hills and Fleurieu is encouraging landholders to undertake maintenance inspections on their dams throughout the year to prevent similar incidents from occuring. The best time for preventative maintenance is in summer, when water levels are low and land is dry. Proper planning can prevent dam wall failure and also benefit the environment by releasing water to downstream catchments before the dam spills.
Landscapes Hills and Fleurieu Team Leader, Water Resources, Paul Wainwright said recent heavy winter and spring rainfall events have created an elevated level of risk with saturated soils and increased runoff.
“With recent heavy rain, we have had significant inflows to dams and we are advising landholders to watch and maintain their dam water levels appropriately, and check spillways are functioning correctly” he said.
Questions for landholders to consider
- Does my dam have an unobstructed spillway operating that ensures the maximum water level is at least half a metre below the top of the dam wall?
- Are there any leaks or signs of animal burrows, cracking, slumping or erosion on the dam wall?
- Is my dam wall free of obstructions and vegetation other than grasses?
- Does my dam need de-silting to maintain its volume?
- Can I exclude livestock where possible?
“If you have questions about dam maintenance or interventions you can make to ensure your dam is effective, please visit our website or reach out to our Landscapes Hills and Fleurieu staff. Proper design of dams and implementing works with qualified, experienced contractors is important to get it right and for landholder safety.
“It can be as simple as opening a trickle pipe or setting up a siphon to enable some flow to pass down the catchment. This can allow ample water to be stored for farm-use, while also preventing dam wall collapse and having a positive impact to support the ongoing health of the catchment you live and work in.
”Some dam maintenance activities have the potential to impact on watercourses and require a water affecting activity permit and it is important to speak with our team before undertaking any modifications to your dam.
“Those who are holding water in dams for primarily aesthetic purposes should also consider their need to retain the same volume of water, and think about releasing some water back into the catchment,” said Mr Wainwright.
The recent dam incident was also a reminder to know what to do in an emergency. There is a guideline and rapid risk assessment tool to provide dam owners and emergency responders with a quick and simple assessment to determine whether further action is needed, if it suspected that a dam safety incident may occur.
The guideline and resources for how to carry out a maintenance inspection and what to do in an emergency situation are available at www.ses.sa.gov.au/flood/during-a-flood/dams
The South Australian State Emergency Services (SASES) can be reached on 132 500 in the case of a flood or storm emergency.
The Department for Environment and Water is the flood hazard leader in South Australia, with further information available at www.environment.sa.gov.au/topics/flood
For further information about the management of dams or water affecting activities, contact Landscapes Hills and Fleurieu on 8391 7500 or visit www.landscape.sa.gov.au/hf/water