Property owners downstream of a dam at risk of failing in the Adelaide Hills fear a potential cascade effect, with another dam directly in the firing line if the top one gives way.
Key points:
- Hope Forest residents are holding their breaths amid efforts to shore up a dam
- They say if it gives way, it could also cause major damage to one downstream
- One says a “massive wall of water” would flood paddocks on his property
A watch-and-act message remains in place for the dam at Hope Forest, where urgent efforts are underway to reduce the water level following torrential rain in recent days.
The State Emergency Service (SES) has been closely monitoring the situation at that dam, and another at Basket Range, both of which are on private land.
Nigel Burgess, who lives near the dam at Hope Forest, said efforts were underway to construct a second spillway to reduce both the water level and the potential impact on a smaller dam downstream.
“We have a breach of the dam wall around halfway on the upper dam which is then spilling over into the lower dam here on this property,” he said.
“We need to get rid of as much water out of that top dam as possible in order to prevent the wall from being breached in any further.
“If the dam wall gave way, we’ve been told, this dam here would also go.”
Mr Burgess said the top dam was “almost three times the volume” of the lower one, which supplies water to his home.
“All of a sudden I’m thinking there’s going to be no water, and there’s going to have to be contingency plans put in place in order to service water to the house,” he said.
“Just pray that everything holds to, and that the wall doesn’t collapse.”
Nicole Rice, who has lived at her current home for 15 years, was advised to leave on Saturday night.
She said the risk of fires over summer was something that she gave thought to, but “never in our wildest dreams did we think we’d get evacuated” for flooding.
“We got the phone call, came home, and then a few of our mates actually came up and helped us,” she said.
“Other neighbours down the road came and helped, and we just went and stayed at the neighbours’.”
But Ms Rice said even if the wall did fail, there was “not going to be any tsunami”, and she decided to return to her home last night.
“I guess if there’s a problem we’ll get a knock at the door and evacuate if we need to,” she said.
Richard McCarthy is confident his home, which is on high ground, is safe — but he said water would likely flood paddocks on his property if the dam were to burst.
“It’s only if there’s a catastrophic collapse of the wall of the dam that would cause a major problem,” he said.
“If the top one broke, it would sort of take away the second dam, and then there’s a lot of other dams downstream.
“There’d probably be a fairly massive wall of water that would come down the valley.
“Most of the water course is pretty empty. There’s only a couple of houses at the bottom.”