Dr Roslyn Irwin, Caniaba
An organisation called ‘Our Future NR’ is distributing and promoting information intended to put the Dunoon Dam, which was excluded from Rous Water’s 2020 Water Strategy, back on the agenda.
Unfortunately, they tell only part of the story. Our region has some of the highest rainfall in New South Wales, and alarmist suggestions that any option other than the dam below Rocky will not secure our water supply into the future is simply untrue. Indeed, it’s fair to say that this region would be the least likely in the State to need another dam.
The closest Rocky Creek Dam came to being unacceptably low was in 2002 when, at the end of the drought, it was at 22.8 per cent.
However, this only happened because the longstanding policy at Rous County Council that restrictions should be implemented when the dam was at 60 per cent full did not occur and, when restrictions were finally implemented, they were far more severe than would have otherwise been necessary.
In contrast, on 13 January 2020, after the far north coast had experienced its longest dry period on record (2018–2020) Rocky Creek Dam was 60.7 per cent full. The Water Services Association of Australia (WSAA) says that being dependent on surface water increases water insecurity, and that a diverse range of water supply sources including new or alternative sources – such as indirect potable reuse and direct reuse of purified water – increases water security.
Several councils in the region have already introduced the use of recycled water, but have not yet introduced purified recycled water for drinking water. For the whole story, go to www.waternorthernrivers.org/.
The dam would inundate 25 graves of the Widjabul Wai-bal people, for whom this is a sacred site. It would also intersect with an important koala food tree corridor used by koalas in a very healthy state owing to their lack of exposure to intensive urban areas with all their dangers. Removal of this koala habitat would simply push koalas further along the path to extinction.
Rous never had system wide restrictions before 2002/3. Something went badly wrong at that time, and a delay in restrictions was only a small part of the reason for the sudden unreliability of the water supply system.
In 2002 Rous supplied water only from Rocky Creek Dam until the water level in Rocky Creek Dam was at 47%, and only then were all the smaller sources operated. This went against long standing practice that when Rocky Creek Dam dropped to 95% all smaller sources would be used to maintain the water level in Rocky Creek Dam. Delaying the startup of the smaller sources probably caused the level of Rocky Creek to be 20-30% below where it should have been and greatly reduced the yield of the water supply system – i.e. Rocky Creek Dam could have been at 42-52% instead of 22%.
Using Rocky Creek Dam almost exclusively as the water supply and ignoring the smaller supplies continued up until 2019-20 when the level in Rocky Creek Dam dropped by 40% in 4 months, because the smaller sources were greatly underused. If all the smaller sources had been used in 2019 then the level in Rocky Creek would never have dropped below 80% and there would have been no panic about water supply reliability.
Based on Rous’s performance and the basic errors in the costing for the preferred option for the Alstonville Groundwater Scheme in their report (~$20million in negative costs – the scheme costs $46m+ instead of the reported $25m), should anyone trust Rous to successfully implement and operate a direct potable reuse water supply scheme? Especially since they have stopped reporting the technical information on their system showing a disregard for transparency and openness.