Council staff recommend permanent Rous connection
From this week, until the end of June, Byron Shire Council is seeking community input on staff’s proposal to connect Mullumbimby’s water to Rous County Council, which supplies other towns in Byron Shire, as well as three other neighbouring shires.
Mullumbimby’s founders demonstrated great foresight 100 years ago when they constructed the Lavertys Gap weir across Wilsons Creek. It provided an independent, reliable source of both electricity and water for the town.
Mullumbimby’s water treatment plant, from the weir, came into existence in 1939, and currently feeds the town’s network via the Azalea Street reservoir.
Following droughts in 2002-03, a study was carried out in 2005, including two workshops with all stakeholders. At those workshops, the Mullumbimby community expressed a strong preference for retaining the Lavertys Gap weir.
Council resolved to retain the supply from the weir. Meanwhile, a pipe was built connecting the eastern half of the town to the supply from Rous, on Gulgan Road, for use in emergencies. Drought returned in 2019, reducing the flow in Wilsons Creek to a trickle in December.
For the first time, and for just 30 days, the emergency supply was turned on to supplement the limited supply from Lavertys Gap before rain replenished the creek flow.
This prompted a review by consultant Hydrosphere of the adequacy and reliability of the supply from Wilsons Creek, as population increases and the risk of more frequent droughts arise owing to climate change.
Construction of the emergency water connection to the Azalea Street reservoir is underway, at a cost of $5m. This is being funded by Council.
The final Hydrosphere report outlines two principal options for the future: continued use of Lavertys Gap, with the addition of water storage in an off-stream reservoir in the valley between Wilsons Creek and the town; or abandonment of the supply from Wilsons Creek and permanent connection to the Rous supply, which Council staff strongly support.
Triple-bottom-line
The local option, continuing to use the local supply from Wilsons Creek, is the preference of the Water and Sewer Advisory Committee (WSAC) because it stacks up better with triple-bottom-line measures.
Principles of triple-bottom-line analysis include contributions to environmental health and social wellbeing, as well as economic analysis. Socially, the local option offers Mullumbimby a far more robust system than relying on Rous.
WSAC members say the local option is also a winner on environmental grounds. By including a reservoir holding three to six months’ supply, the creek itself will not need to be tapped into in times of flood, nor during drought.
Rous, on the other hand are still searching for new supplies to satisfy growth in the four shires that they service. They have not yet found the reliable supplies that they need, and are still considering building the Dunoon Dam, which would flood a pristine river valley that contains significant First Nations cultural heritage. Dams on existing rivers generally have environmental impacts that off-stream reservoirs, like those proposed for Mullumbimby, do not.
In the economic contest between the options, neither has been adequately examined. Nobody knows what Rous will charge for water in 2040 or beyond. Rous doesn’t even know. Continuing to use water from Lavertys Gap will require some short-to medium-term expenditure.
A new water treatment plant will be required to replace the existing 85-year-old plant, which is beyond its useful life; this is estimated by Hydrosphere at $6.7m.
In addition, an off-stream storage reservoir could be constructed in the future for $10–20m. Such reservoirs are being built in several other NSW regional towns.
The Mullumbimby Residents Association (MRA) say they prefer the Lavertys Gap option rather than connecting the town to Rous. They say consultation and information gathering is preferable to a rushed decision before the upcoming Council elections.
MRA is holding a public meeting on the matter at Mullum Ex-Services Club from 7pm on Monday, June 17. A panel will describe what’s happening and answer your questions.
To visit the Lavertys Gap Weir email [email protected] before June 16.
• Ben Fawcett is a water and sanitation engineer, resident of Lavertys Gap, and community member of Council’s Water and Sewer Advisory Committee.
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