By JAMES WOODFORD
Where do fish look when they are locked in an elevator together?
It is a question that will remain a mystery for a little longer, says the Sydney Catchment Authority’s senior environmental manager, Tony Paull.
Even so, elevator etiquette was a crucial consideration for the state’s first ‘fish lift’ which was officially opened yesterday by the NSW water minister Phil Costa.
“This new fish lift is the largest of its kind in Australia and a direct investment into improving the health of this vital river system,” Mr Costa said.
The fish lift is being touted as a solution to one of the biggest ecological problems facing one of NSW most beautiful but troubled rivers – the Shoalhaven.
Tallowa Dam, which forms a crucial back-up to Sydney’s water supply, has been a Berlin Wall for fish and other aquatic organisms. Only eels and gudgeons have the climbing skills to haul themselves up and over the 43-metre-high wall.
The existence of the dam wall is thought to have led to the local extinction of up to 10 native fish species, which have to migrate upstream in order to complete their life cycle.
As part of its program to improve environmental flows on the Shoalhaven, the government committed itself to somehow getting fish from one side of the wall to the other.
A standard fish passage was ruled out as it would have had to have been a kilometre long to be at a gradient that fish could actually use, Mr Paull said.
Instead the NSW Government decided to build a fish lift. The idea is simple but bizarre. When fish hit the dam wall they are now met by an enticing flow of water from upstream. When they follow this “attraction flow” they end up being guided into a 2,500 litre ‘hopper’. The doors are closed 18 times a day and the whole contraption with fish, water and anything else that ends up in the lift is carried over the wall and released.
Perhaps the most incredible thing about the fish lift is that scientists have already shown from tagged fish that it is actually being used.
The Sydney Catchment Authority has banned angling near where the fish are released and has also established refuge habitats for smaller fish to hide as soon as they are released upstream.
Scientists considered installing a camera inside the lift so they could study the fish but in the end decided to settle for making sure there was safe places for prey to hide during the ferry ride over the wall.
“They can hide and be separate from each other if they don’t like the look of their travelling companions,” Mr Paull said.
In order to ensure fish can migrate downstream the Authority has recoated the spillway with a special surface that allows creatures to tumble down without harm. A plunge pool has also been created so fish aren’t smashed on landing. New environmental flows are also improving the health of the river downstream. Altogether $26 million has been spent on the project – about a third of which has gone on the fish lift component.
“Once the water warms up in spring we think we are going to see a lot more fish starting to move,” Mr Paull said.
First published Sydney Morning Herald 24/08/09
A hi-tek fix to a problem that should never have been created. Better than nothing.
What is actually amazing is that Sydney uses lesss water now than 20 yrs ago, NOT per capita but in toto, with almost double the population!!
It shows that even urbanoids care enough to change their god/gov given right to be profligate as they become aware of what we are facing in climate change.
So far it has been only a logical argument – within a generation it’ll be a physical fact so, as a card carrying cynic, I’m impressed.
I knew this was being built. Good to hear it has been launched.
Lets hope that the privateers who wish to pump Tallowa Dam water to the Murrumbidgee and Lachlan Rivers do not get the go ahead.
Seriously – there are plans afoot – from what I hear from well-placed sources.
Their argument is that by the time their plans are ready to g, Sydney will have a Desal Plant, and will no longer need the Shoalhaven Water as an emergency back up.
But given the huge expense on the public purse, how does that justify a private group gaining access to the Shoalhaven Water, for them to on-sell to irrigators, or to Penny Wong?
It is just wrong, and must be stopped in its tracks.
Cheers
Denis Wilson
Robertson
There might be a growing demand for water for Sydney but half baked ideas for future diversions of the Shoalhaven show that nothing was learned from the ruination of rivers like the Snowy, hence the Shoalhaven is now a shadow of its former self. It has been interesting to watch the lack of interest from conservation groups in this issue over the past few years, eg the NCC campaigned strongly against the desal plant at Botany Bay, but had nothing to say about years of water diversions robbing the lower Shoalhaven of its lifeblood. The further these problems are from Sydney the less attention they seem to get.
Peter G – I think (?) the lack of interest in this issue is not because conservation groups disagree with you. Just a lack of capacity on their part. Hopefully the three year moratorium on transfers out of Tallowa is an indication that long term flows will be restored and any additional diversions will not occur.
Perhaps they do lack capacity – that’s understandable and realistic situation for many such organisations – but nonetheless if you look at the media release archives on the NCC website you have to go back three years before you find a media release about the Shoalhaven problem. Local environmental groups on the South Coast certainly kept up a fight but I still reckon the city-based groups let them down, despite drinking so much of the water!