Mayoral Column - Dannevirke Water Supply Update

05 June 2023

Mayoral Update on the Dannevirke Water Supply

Council received the latest update on the Dannevirke Impounded Supply at this month’s council meeting. There is still a risk of an uncontrolled release of water, where the eastern side wall had early signs of a wetter patch. The maximum operating water level was dropped when the wet patch was first noticed and is monitored on a daily basis. Impacted neighbours have been contacted and plans put in place to model the impacts if this eventuated.

The largest risk is to the day-to-day supply of water to the town. Complete failure of the impounded supply would result in water being taken and treated directly from the Tamaki River. This would be fine if the river flow and quality were stable, but would create disruption during times of low flow or very high flow when the water is turbid.

Divers plan to enter the dam this month to fix the two further identified leaks. It was interesting to hear the complexity of this job and that the divers are simulating the exercise to ensure it goes as smoothly as possible. This will also provide further information on the condition at the bottom of the dam and insight into the water flows.

The information in the council papers gave a thorough history and reporting on the dam, including some presentation slides from the optioneering exercise that our team, iwi and experts took part in. We are committed to transparency and keeping everyone informed of exactly what is happening. For those interested this is available on the council website and the team will produce an executive summary also. A public meeting is being planned which will follow the diver’s entrance for us to include the findings.

The key message is water conservation and planning will be required as we move forward. We are looking to progress metering of connections on the main lines between the Tamaki River and Dannevirke to understand the usage. Council is working closely with our large water users, looking for an alternate source for the Alliance Plant and encouraging residents to think about what resilience looks like at your home. Being prepared for a shortage and understanding what essential use is, helps. We have time to plan for a worst-case scenario while we work towards a solution of providing adequate water supply while the dam is out of action and what that repair or build will look like. It will cost millions and it must be both resilient and future proof, along with meeting the new dam safety regulations which have significantly increased since the dam was built, and we can understand why as we face this crisis.

Noho ora mai, All the best,
Tracey Collis - Mayor