Public meeting on Dannevirke water barely raises a ripple

Three Waters manager Roger Earp presents the impounded supply situation. Photo / Dave Murdoch

Plans for the future security of Dannevirke’s water supply are in a holding pattern pending research results, residents were told at a public meeting.

It was discovered in July 2021 that the impounded supply, also called the dam, on Laws Road had been leaking and investigations had been carried out since then to locate the source and causes of the leak.

Not a lot had changed since the extraordinary meeting of Tararua District Council in October at which the issue of $6 million being allocated for measures to secure the immediate supply was voted on because information on the stability of the eastern - and now western - walls of the impounded supply was still to come, the drilling for alternative water sources is currently happening with no conclusive successful results so far and the change of government meant the Three Waters reform would be repealed.

The council is still awaiting information on Dannevirke's dam. Photo / Paul Taylor

It was stressed by council chief executive Bryan Nicholson that the target was still to secure “a safe, reliable water supply for Dannevirke, and to achieve that, all information must be available and decisions on future actions following advice from favoured engineers Tonkin and Taylor [and] peer-reviewed by Dam Watch are taken into account”.

Council Three Waters manager Roger Earp gave some background to the process of decision-making so far, highlighting the plan to install a KlipTank to store untreated water from Tāmaki above a newly installed treatment plant and to build a new treated water storage tank next to the existing one which would give Dannevirke four to five days’ supply depending on demand. These should be in place early in the new year.

Nicholson reminded the audience the impounded supply would still be in use at lower capacity as the repair of it is now delayed until the 2024-25 summer.

Questions on its safety were covered by the constant monitoring process which was currently already under way, and a person who questioned the safety of residents if there was a breach was assured the flow down the Makirikiri Stream would be minimal by the time it reached the town.

Seeking alternative sources of water through bores had not yet reached a successful stage. Drilling near the Alliance works had shown water to be insufficient to replace the impounded supply, which needs a flow of 25 litres per second.

Laws Road testing was currently inconclusive.

Leaks in the impounded supply have been reduced from flows of 25 litres per second to 2.5 litres per second following repairs.

The summer is forecast to be dry and there will be restrictions. Right now, the impounded supply is full, and residents are asked to use it now for swimming pools, water blasting and other uses while it is still available.

After the summary of the situation, Tararua Mayor Tracey Collis directed 20 questions from the floor to various speakers - mostly Roger Earp - which covered:

• How soon anything will start – Early next year.
• Alternatives to the impounded supply – Not really investigated yet.
• Risk of dam collapse to residents – Minimal.
• Subsidising houses to have their own tanks – Too expensive.
• Capacity to pay off loan – There is flexibility and it will be paid over 40 years.
• Extracting more water through Horizons consents - A tough challenge.
• Risk of pine pollen in water as pine plantations spread – Can be filtered.
• Threat of earthquakes – Plans are in place.

The crowd leaves after a productive meeting. Photo / Dave Murdoch

Some questions related to recovering costs from the original impounded supply builders, which was deemed too difficult and expensive to pursue.

The fate of the impounded supply was the central matter from the floor. Roger Earp said all the best advice showed that the impounded supply was a huge asset and should be repaired, but he admitted costs of that operation might yet be too high if Geotech figures were bad, and it might be back to the drawing board.

Dave Murdoch is a part-time photojournalist working for the Bush Telegraph based in Dannevirke. He has covered any community story relaying good news about the district for the last 10 years.