Strelow defends not spending on Rookwood for water security
ROCKHAMPTON Regional Council could play a pivotal role in the future economic viability for the Rookwood Weir project, according to the recently released business case.
With questions raised about whether Rockhampton's water supply could hold up in the face of a multi-year drought scenario, the Rookwood Weir project represented an opportunity for Rockhampton to have a guaranteed water supply.
In the key risks section of Rookwood's business case, which was conducted by Building Queensland last year, they were uncertain what specific measures would be adopted by the water supply strategy under development by Rockhampton Regional Council.
"The measures adopted will impact on the water security risks faced by Rockhampton and consequently, the benefits associated with the development of Rookwood Weir," the document said.
It is understood that if RRC were to seek an allocation of Rookwood's water, the financial viability of the project would be increased and could help the project over the line to unlock the economic benefits including increased employment and agricultural expansion.
Rockhampton Region Mayor Margaret Strelow said "clearly the business case for Rookwood would be stronger if we committed to buying water for our urban use" but "the plans and studies for the new storage have never included water for Rockhampton's urban use".
Cr Strelow said although their storage was small, RRC was not using their existing water allocation.
"We own an allocation of 50,000 ML High Priority water and only use around half each year," she said.
"We are not keen to pay (and keep on paying) for an additional allocation in another storage when we have a more than adequate allocation already."
She explained the rationale behind not contributing money towards the project to assist other regions with their water security.
"It's like we're all crowded at our house because our next-door neighbour is there all the time. If the neighbours get their own place our problems are solved," Cr Strelow said.
"That said, the answer is not for us to rent another house to give our neighbour more room.
"So yes, we want Rookwood for many reasons - not the least of which is improved water security for Rockhampton."
The business case projected the population of Rockhampton to grow by 0.98 per cent per annum and temperatures across the region to rise over the remainder of the century due to the impacts of climate change.
"By 2030, it was anticipated there will be longer, drier periods, interrupted by more intense rainfall events," the report said.
"By 2070, under a 'high emissions scenario, it is likely that eastern parts of the region will experience more time in drought', including Rockhampton and Gladstone."
The Fitzroy Barrage was cited by the report to be heavily reliant on seasonal inflows from the Fitzroy River to maintain continuity of supply, particularly in the occurrence of annual wet season events.
"The Rockhampton Regional Water Supply Security Assessment (RWSSA) 'estimated that at current levels of demand, the storages could fall from full to empty in about 16 months'," it said.
"However, further analysis demonstrates storage levels could fall from full to below minimum operating level well under 12 months assuming no further inflows to the storages during this period and minimal groundwater contributions from the surrounding area to the storage."
Cr Strelow said concerns about Rockhampton running out of water in a certain number of months came from a report that was done some years ago assessing the likelihood of a failure of the Barrage at any given time and was based on a long line of 'ifs' and assumed no steps would be taken to counteract a drought-like scenario.
She said Rockhampton Council's water was high-priority water and the incidence of failure (on the scenario modelled) is one year out of every 100 years and lasting between one and six months.
"The water security report that people are referring to assumed several things with the first assumption that we will have two consecutive dry seasons," she said.
"It also assumed that Livingstone Shire will continue to take water from the Barrage instead of drawing from their own allocation at Rookwood Weir."
Livingstone currently pays for one sixth of the urban use water from the Barrage.
"They are our biggest single customer and when they cease to draw from behind the Barrage this will give considerable improvement to our own water reliability," she said.
Cr Strelow said the report also assumed that Council would not implement any kind of water restrictions as the Barrage water level drops, which they would obviously do if we had consecutive dry seasons.
Another failing of the the report was the assumption that Council would not take steps to increase reliability of the existing storage.
"We can lower the intake point behind the Barrage which gives us access to a pond of 'dead' water that could otherwise not be reached and we believe we can raise the Barrage height by around 40cm," she said.
"These projects are still subject to approvals and consultation.
"It doesn't give us a bigger allocation (which we don't need) but will help improve the reliability of what we already have."
Cr Strelow said they remained very committed to supporting Rookwood and acknowledged that it may be that ultimately (in a decade or three or four) Rockhampton does need water from Rookwood but they were a long way from being able to quantify that or to put a timeline on it.
"And there is no reason for us to start paying out on the basis of 'maybe'," she said.
The mayor also pointed out that water security modelling for dams, which typically catch a lot of water in a large 'pondage' after a heavy flow, was dissimilar to the constant flow which supplied the Barrage.
"Our water reliability comes from almost constant flows given the size of our river catchment not just from the amount of water held at any one time," Cr Strelow said.
"History has shown we have remarkable reliability even though, at any one time, there is only a modest amount of water in our Barrage poundage.
"There is always a bit of rain in the catchment somewhere."
Cr Strelow acknowledged construction of Rookwood Weir would help to ensure the reliability of Rockhampton's existing water allocation if the rules of operation of the Weir are well managed.