Dam wall to be raised at Warragamba – ABC Sydney – Australian Broadcasting Corporation
The Federal Government are planning to spend $50 million dollars over ten years to raise the wall of Warragamba Dam.
It is set to be matched by the state government and should lower insurance premiums for people living in the area.
Insurance premiums in the Hawkesbury area have gone up by a significant amount in the last few years, as Hawkesbury Mayor, Kim Ford, explains;
“Depending on where people are, some premiums (in this area) have gone up by $8,000.
A lot of people can’t afford to pay that and perhaps they take the risk.
A few people in those areas can’t increase their income that much to cover it” said Ford.
Protecting the area from flood damage by looking at mitigation and raising the wall by 23 metres is a plan welcomed by the Mayor.
“I’m happy, I’d take the mitigation any way it comes…
The dam for mitigation would be a great effort and would make a great difference. In an ordinary flood event it would make a difference of one or two metres, which keeps bridges open and water out of houses” said Ford.
Insurance companies have welcomed the news.
“We congratulate the Federal Government and Minister Shorten for providing this breakthrough funding for vital flood mitigation infrastructure work,” said Mr Rob Whelan, CEO of the Insurance Council of Australia.
“The announcement today will ensure that at-risk Australian communities will be better protected in the future from the devastating effects of floods” said Whelan.
The plan does have wider environmental concerns.
Richard Kingsford, a Professor of Environmental Science at UNSW is one of Australia’s foremost experts on river systems & inland waterways.
“Building dams on rivers, and, raising dam walls causes incredible ecological damage to the river.
It’s because they trap the water that is essential for that river system.
When you think of a river you tend to think of the main channel but it’s a lot more than that.
It actually relies on the flood plains, on it’s sides, that’s where a lot of nutrients come from.
Then of course, at the mouth of a river there is usually an estuary.
That’s highly dependent on what comes down the river in terms of nutrients and sediment.
We are talking there about our most productive areas for nursery fisheries and oyster farmers” said Professor Kingsford.
Danielle Wheeler, a Wilberforce resident & member of Hawkesbury Greens also addressed the environmental impact on the rivers when she spoke to Linda Mottram two weeks ago:
“Raising the dam wall is pretty short sighted and really expensive in terms of money and impact.
We will spend billions raising a dam wall and entirely destroying a river system.. this river is down to about 5 percent of it’s flow in dry times anyway, it’s given a token amount of water to keep it going and the rest of the flow in the river comes from sewage treatment plants” said Wheeler.
Professor Kingsford thinks that more questions need to be asked of the plan.
“Raising a dam wall will certainly help in terms of flood mitigation. The critical question , where we need some transparency, is, where are the different flooding regimes going to occur? Where is the 1 in 100 hundred flood? Where is the 1 in 1000 flood going to actually go? How many of those houses are actually going to be protected? The other difficult part of this issue is what are the affects of climate change?” said Kingsford.
Wheeler also discussed the affect that the height change might have.
“Even if we do raise that dam height, even where I live in Wilberforce, I’m past the 1 in 100 year flood mark.
So in a maximum possible flood, my house would be eight metres under water without any change to the dam wall.
I’m on one of the highest points of the river.
If the dam wall was raised, I would still be 3 or 4 metres under water.
It’s not going to save towns like Bligh Park, South Windsor of McGraths’s Hill” said Wheeler.