There are more than 22,000 legitimate dams in the Mount Lofty Ranges, but high-resolution aerial imagery has identified around 400 new dams that have been illegally constructed in the last 10 years, and around 300 existing dams that have been illegally enlarged.

As a result, the Hills and Fleurieu Landscape Board is increasing efforts to educate land managers about their water management responsibilities, and working to remove illegal dams so water can get to legitimate users.

General Manager Michael Garrod says this is of particular concern given there has been a moratorium on building new dams in the area since 2013.

“Water catchments in the Mount Lofty Ranges were under stress even before the current drought, and this illegal water storage will worsen the situation. These new dams will reduce water availability for legitimate water users, including rural landholders, industries, primary producers, and the environment,” he says.

“Capturing water in an illegal dam amounts to water theft. When more dams are built or enlarged, less water flows downstream, and that can leave legitimate water users struggling to meet their domestic and primary production needs.

“It also means that vulnerable aquatic ecosystems are robbed of the water they need to survive. We could see the local extinction of many threatened species, like the southern pygmy perch and the mountain galaxias, if they don’t receive the water they need.

“With climate change resulting in the region facing drier and more variable conditions, fair and responsible water management is more important than ever. All land managers planning work in a watercourse or on a dam should be obtaining development approval or a water affecting activity permit.

“This system exists to ensure fair distribution of available water and protect the environment,” Mr Garrod says.

Compliance officers are reviewing dams across the Adelaide Hills and southern Fleurieu to identify those built or enlarged without approval. 

While several hundred illegal dams have been identified, some are linked to single landholders who have built multiple dams. 

Mr Garrod says  overall, most landholders are doing the right thing.

“Given the seriousness of the issue, the state government has provided additional funding to support our increased education and compliance efforts.

“We want to work with land managers to ensure they have the right information and advice to meet their legal responsibilities. Encouragingly, most landholders contacted by our compliance team so far are taking the necessary steps to address any issues.

“If a dam has been built or enlarged without authorisation, or if there’s uncertainty about whether it is compliant, we encourage land managers to discuss the matter with us. We’ll work together to achieve the best outcome for everybody.”

Where a landholder refuses to voluntarily rectify an illegal activity they can be compelled to act, and risk penalties if they do not.

“To strengthen our monitoring, we’re also developing an automated satellite imagery ‘change detection system’, which will allow us to quickly identify new and enlarged dams,” Mr Garrod says.

For more information visit the Landscape SA website.