Hundreds of dams across the Adelaide Hills pose a threat to people and property, review finds

Hundreds of private dams across swathes of the Adelaide Hills and Fleurieu Peninsula are a potential flood “threat” to people or property, an official review has found. See the list.

Hundreds of private dams across swathes of the Adelaide Hills and Fleurieu are a potential flood “threat” to people or property, an official review has found.

The Environment and Water Department inspected almost 6300 dams, or watering holes, after a partial levee collapse threatened to inundate Hills homes at Echunga in September last year.

Authorities found 460 dams in the Onkaparinga and Angas river catchment zones where “failure would potentially pose a flood risk” to communities, industries or parks local areas.

SES volunteers on the edge of the dam at Echunga after a night of reducing the water levels in the dam to stop potential flooding. Picture: Kelly Barnes

Special satellite imaging, along with analysis of water volumes and local geography found almost two dozen dams posed multiple “threats” to people, homes, property or assets such as roads from any potential embankment failures.

Woodside’s 48 at risk dams was the Hills’ highest, followed by 45 in Lenswood and 40 at Lobethal.

The review, which also involved government landscape boards, found risks were due to locations and not structural failures as many dams were built in the 1950s or 1960s, prior to planning controls.

Authorities averted disaster after pumping water out of the full dam located on a farm near Echunga in the Adelaide Hills. Picture: Kelly Barnes

Community leaders have raised concerns at potential costs for farmers and property owners, for improving dams that were filled during last winter’s extensive rains.

More taxpayer funds will likely be allocated in next month’s state budget for a “package of works” to improve dam safety, levee bank overhauls, flood mapping and community information.

The state government is also seeking more money from the Commonwealth Disaster Ready Fund.

Onkaparinga River Catchment area. Picture: state government

Environment officials, State Emergency Service, Hills and Fleurieu and Northern and Yorke landscape boards are working with councils, contractors and landholders to improve dam safety and reduce flooding risks.

Angus River catchment area. Picture: state government

Deputy Premier Susan Close said new works are due to start from July while special education campaigns had targeted landholders, councils and other contractors.

“Dam owners are encouraged to conduct routine maintenance to better understand their dams,” said Dr Close, the Environment Minister.

“Regularly checking dams helps owners to spot any defects while they are relatively minor. This reduces the risk of failure, prolongs the life of the dam and makes repair work less costly.”

There are more than 22,000 farm dams in the Mt Lofty Ranges alone, according to a June 2020 position paper.

The paper’s 13 findings included developing annual safety campaigns especially around emergency plans, creating a special register and introducing new flood prevention rules similar to annual bushfire checklists.

Deputy Premier Susan Close hoped works would start from July. NCA NewsWire / David Mariuz

Lower House speaker Dan Cregan said it was important that small land owners were not left facing substantial costs for any upgrades. Picture: NCA NewsWire / Naomi Jellicoe

Authorities warn owners they are “accountable” for damage from any dam failures.

New dams need approval under the Landscape SA Act.

Lower House speaker Dan Cregan, whose electorate covers many at risk areas, said private dams were needed in communities for vital stock and fire water in summer.

“However small land owners can’t face the real engineering challenges and risks of managing dams – especially large dams – on their own,” he said.

“This is an issue we have raised with the Deputy Premier and I am hopeful additional funds will hit the ground.”

Echunga dam aerial from Satellite imagery shows where the issues were: picture: Metromap

Opposition Leader David Speirs, a former Liberal Environment Minister, said “clear communication” was needed about how to handle repairs as we head into winter and high rainfall.

“If repair works are warranted, will the costs be lumped on property owners, councils, or will Labor provide support to affected land owners,” he said.

Originally published as Hundreds of dams across the Adelaide Hills pose a threat to people and property, review finds