Current Water Restrictions

Water restriction system gauge for the Tararua District signage

  • Ākitio: Total Outdoor Ban
  • Dannevirke: Get ready (no restrictions)
  • Eketāhuna: Get Ready (no restrictions)
  • Norsewood: Get Ready (no restrictions)
  • Pahiatua:  Get Ready (no restrictions)
  • Pongaroa: Get ready (no restrictions)
  • Woodville: Get Ready (no restrictions)

Restriction Definitions

Alternate Day Restrictions

Hand-held hoses only on alternate days, i.e. houses with even street numbers on even days and houses with odd street numbers on odd days.
Examples of Hand-held hoses include sprinklers, hoses and water blasters 

Alternate Evening Restrictions

Hand-held hoses only on alternate evenings between 7pm - 9pm i.e. houses with even street numbers on even nights and houses with odd street numbers on odd nights.
Examples of Hand-held hoses include sprinklers, hoses and water blasters

Total Outdoor Ban

You may not:

  • Use sprinklers
  • Use soak hoses
  • Use irrigation systems
  • Hose gardens
  • Water blasters
  • Wash vehicles, buildings or boats

You may:

  • Use buckets and watering cans to water gardens

Essential Use Only

You may not:

  • Use water anywhere outside (unless is it recycled water/greywater)

You may:

  • Use water for cleaning and cooking
  • Use water to wash clothes and take showers
Under the Total Outdoor Ban restrictions, there is a process to apply for extraordinary water use. Council will consider exemptions, for example for businesses. After completing the form please submit it to info@tararuadc.govt.nz or bring it to one of our service centres. Our teams will then assess the request and contact you. The Application form is available here.

Latest Update:

27 March 2024

Majority of water restrictions removed in the Tararua District.

With recent rainfall and stable river levels all water restrictions  in the Tararua District, with the exception of Ākitio, have been removed.  Ākitio remains on Total Outdoor Ban while all other towns have been reduced to Get Ready (no restrictions).

Previous Update:

25 January 2024

Woodville moved to Alternate Evening Restrictions.  

Woodville's water demand has not significantly reduced since moving to alternate day restrictions on 10 January.  Average daily demand has been 1050 - 1250m³ /day.  As a result it has been neccesasry to increaese Woodville's water restiction to alternate evenings.

18 January 2024

Eketāhuna and Pahiatua move to Alternate Day Restrictions.  Woodville remains on Alternate  Day Restriction

Due to higher than average demand in Eketāhuna and Pahiatua, those water supplies have been raised from "Get Ready" to Alternate Day Restrictions.  Woodville was placed on an Alternate Day Restriction for the same reason on 10 January but there has been no significant reduction in demand, meaning that Woodville will remain on their Alternate Day Restriction for the time being.

10 January 2024

Woodville moves to Alternate Day Restrictions

Due to low flow in the Mangapapa Stream and the long term weather forecast showing no significant rainfall in the immediate future, Woodville has been raised from No Restrictions to Alternate Day restrictions.  No other towns in the district have had a restriction change at this time.

1 December 2023

Ākitio moves to a Total Outdoor Ban

This is the annual water restriction placed on Ākitio for the summer period.  The restrition will be reviewed regulary and lifted at the earliest opportunity

26 September 2023

The Pahiatua Total Outdoor Ban has been reduced to Get Ready (no restrictions)

11 September 2023

Pahiatua placed on a Total Outdoor Ban

The Pahiatua water treatment plant  treated water output  is running at a reduced capacity and water levels in  the new reservoir are critically low.  A letter drop has been conducted informing residents of  the water restriction and the need to conserve water.

2 May 2023

Ākitio water restriction reduces from Total Outdoor Ban to No Restrictions

13 March 2023

Dannevirke water restriction reduces from Alternate Days to No Restrictions

The decision to reduce  the water restriction level for Dannevirke is due to the water level in the reservoir being satisfactory and improved turbidity levels in the Tamaki River.  We ask that everyone continues to practice water conservation techniques.

28 February  2023

Pahiatua water restriction reduces from Alternate Days to No Restrictions

The decision to reduce  the water restriction level for Pahiatua  comes with a request for residents to practice water conservation techniques  to  reduce  the risk of going up a level  in the short term

22 February  2023

Dannevirke has had its water restriction raised from Get Ready (No Restrictions) to Alternate Days

The decision to increase  the water restriction level for Dannevirke is due to high turbidity levels in the Tamaki River,  Town supply is being drawn directly from the impounded town supply much of the time.  When we are able to we are recharging the impounded water supply but rainfall will spike turbidity levels forcing us to stop recharging.  Therefore, the impounded supply can not be recharged as quickly as we would like because of this.   We urge all residents to practice water conservation techniques

26 January 2023

The first water restriction increase for 2023 has been issued for Pahiatua, to take place from 26 January 2023

The decision to raise the water restriction level for Pahiatua  has been made  due to  the following reasons:

  • High water consumption
  • Falling river flows
  • Water  storage  reservoirs not filling to capacity.

As  a result, Pahiatua's  water restriction  has changed from  No Restrictions to  Alternate Days.  As we proceed through summer  it is  possible further changes  could occur.

30 November 2022

Scheduled increase to Ākitio's water restriction to take place from 1 December 2022

The scheduled annual water restriction increase for Ākitio will take place on 1 December  2022 rising from "Get ready" to "Total  outdoor  ban".

This is an annual scheduled summer increase in water restriction specifically put in place for Ākitio that occurs every year on 1 December.

Ākitio's water restriction will be reviewed periodically and relaxed at the earliest opportunity, most likely in the Autumn.

16 September 2022

Temporary  reduction to Dannevirke's  water restriction to Get Ready (No Restrictions)

Many will be aware of the ongoing challenges with Dannevirke’s impounded supply (or untreated water reservoir / dam). If not, you can read the latest update here: https://www.tararuadc.govt.nz/dvk-reservoir

The impounded supply is still leaking and we are operating it to a maximum height of 9.5 metres to mitigate risks on the dam wall, as recommended by external dam advisers. With the Tamaki River at relative stable flows, we see a window of opportunity where we are comfortable in temporarily removing Dannevirke’s water restrictions.

With restrictions removed, we encourage Dannevirke residents to fill up their pools and/or water tanks, and complete jobs like water blasting, while the water source is stable. It is almost certain that some level of water restriction will be required later in the year, when the Tamaki River goes into low flows and there is a reduced volume of stored water in the impounded supply. So take the opportunity now to prepare for summer.

It should be noted that we will be going into this summer with far more water stored in the impounded supply, compared to last summer when initial repairs to the impounded supply resulted in it only being 4.2 metres full in October.

We appreciate that ongoing issues with Dannevirke’s water supply is frustrating, and appreciate your patience as we seek to implement a good, long term solution to this.


25 July 2022

It’s been a while since our last update on water restrictions across the district with a lot happening in the water space since May. So, we thought we would provide a brief update on our supplies:

Pahiatua: Reducing to No Restrictions (get ready)

There has been a healthy amount of rain over the past month which has replenished the Mangatainoka River to a point where consistent water is able to be taken. We would like to commend Pahiatua residents for their patience during this extended period.

Norsewood: No change at Alternate Day Restrictions

Norsewood residents are still consistently using more water than the permitted extraction from the bore. For alternate day restrictions to be removed a large community effort is needed to reduce usage, for some tips and tricks you can visit: https://www.tararuadc.govt.nz/services/water-and-wastewater/water-conservation-tips

Please note that Council has put budget over the next 2 years aside to address this supply issue.

Dannevirke: No change at Alternate Day Restrictions

Many will be aware of the ongoing challenges with Dannevirke’s impounded supply. If not, you can read the latest update here: https://www.tararuadc.govt.nz/dvk-reservoir

Due to this we will be keeping the alternate day restrictions in place. We understand that this will be frustrating, however with the current weather we hope that limiting outdoor water usage to alternate days will have minimal effect on our residents. Finally, Council would like to extend a thank you to you all for your patience over the past year as we work to resolve this ongoing challenge.

All other supplies: No restrictions

25 May 2022

Water restrictions reducing, but conservation still a focus for the Tararua District.

Dannevirke: Reducing to Alternative Day Restrictions

Progress has been made getting water into the impounded supply, Dannevirke’s raw water storage dam. This is now around 10 metres full.

We continue to investigate issues with the impounded supply and wider water supply network, to develop plans to address the short and long term challenges, however are comfortable in relaxing the water restriction level to Alternate Day Restrictions.

Norsewood: Reducing to Alternate Day Restrictions

Norsewood’s water consumption is still consistently high, placing pressure on the bore where water is sourced. We ask residents to continue conserving water, and to report any water leaks to Council’s customer services team.

Pahiatua: Reducing to Alternate Day Restrictions

The Mangatainoka River level has increased recently, enabling the abstraction of water. With current usage levels we are comfortable in reducing the restriction level to Alternate Day Restrictions.

Woodville: Reducing to Get Ready (No Restrictions)

Water consumption has remained relatively stable, and we are happy with the volume of water currently stored in the impounded supply.  We are comfortable in reducing Woodville’s water restriction to Get Ready (No Restrictions).

We ask that all users of town water supplies use water smartly, reducing pressure on the systems. We are becoming increasingly aware of unmetered connections to some of the extraordinary water lines (outside the urban town boundaries) and ask those landowners to contact Council’s customer services team so that these can be recorded. Water is a precious resource, and we encourage you to be smart with water all year round.

All water users are encouraged to use water wisely. You can find handy ways to conserve water here: https://www.tararuadc.govt.nz/services/water-and-wastewater/water-conservation-tips


29 April 2022

Water conservation still a focus for the Tararua District.

The weather forecast for the next week looks great for school holidays, but it’s not the best for our water supplies. Many of the rivers that provide water for our towns are in low flow, and this isn’t expected to improve in the near future.

Dannevirke: Reducing to Alternative Evening Restrictions

While the Tamaki River flow has dropped is recent weeks, and continues to do so, there was been progress made getting water into the impounded supply, Dannevirke’s raw water storage dam. This is now around 9.5 metres full.

More work is underway and being planned to address the short and long term challenges with the impounded supply and smart use of water is still required, however we are comfortable in relaxing the water restriction level – moving to alternate evening restrictions - for now.

Pahiatua: No change at Alternate Evening Restrictions

The Mangatainoka River is in low flow which is impacting the volume of water that can be abstracted for treatment. We continue to work with Horizons Regional Council on the river weir, which significantly influences the performance of the infiltration gallery and amount of water that can be taken, with a view to implementing a solution that meets both the needs of community in terms of water supply and Horizons’ environmental expectations.

Norsewood: No change at Alternate Evening Restrictions

Norsewood’s water consumption is still consistently high, placing pressure on the bore where water is sourced. We ask residents to please continue conserving water, and to report and water leaks to Council’s customer services team.

Woodville: Reducing to Alternate Day Restrictions

Water consumption has been relatively good, and we are comfortable in the amount of water currently stored in the impounded supply. If this continues, and there is minimal risk of low flow at the Mangapapa River which supplies Woodville’s water, we hope to lift restrictions completely in the near future.

Akitio: Reducing to No Restrictions

Akitio has a summer Total Outdoor Ban from December through to after Easter. This has now been removed.

Eketāhuna: Remains on No Restrictions

There are no current concerns regarding Eketāhuna’s water supply and consumption, although we continue to work through issues associated with water quality.

All water users are encouraged to use water wisely. You can find handy ways to conserve water here: https://www.tararuadc.govt.nz/services/water-and-wastewater/water-conservation-tips


4 March 2022

The water restriction level for Pahiatua has been reduced from Total Outdoor Ban to Alternate Evening Restrictions.

This means that from now onwards handheld hoses can be used on alternate evenings between 7pm and 9pm, i.e. houses with street number on even nights and houses with odd street numbers on odd nights.

The Total Outdoor Ban in Pahiatua has been in place since 25 January 2022.

Pressure on the Pahiatua water reservoir has reduced, as over the last few weeks Pahiatua residents have rallied together to save water which has resulted in a steady reduction of water use. In addition, work on the water intake point at the Mangatainoka River can now be finished without having to further rely on water from the reservoir.  As river levels are dropping, it is still necessary to keep up the great efforts of saving water.

Council would like to say thank you to Pahiatua residents for their support and continuing efforts to conserve water. Council would also like to thank teams who have been working hard to improve the Pahiatua water infrastructure.

For a full explanation what the various restrictions mean please refer to this link.


23 February 2022

Water Conservation still a focus for the Tararua District.

While there is some scattered rain forecast over the next 10 days, it is not expected to be substantial or prolonged and benefits to water supplies will be minimal, therefore the decision has been made for no reductions in restriction levels at this time.

Rivers across the Tararua District did benefit from the recent rain, however they are already starting to drop. A common misconception is that the heavy rain over recent weekends must have fill up Council’s water storage dams and reservoirs – however the heavy rain also creates a lot of silt and other material in the rivers where water is taken, actually reducing what can be taken until this settles out. Therefore, we need to remain conservative in our water usage, particularly for Dannevirke and Pahiatua.

Dannevirke: Total Hosing Ban

The recent rain has allowed us to increase the take from the river, with surplus water going into the impounded supply (our raw water storage dam). This has recently improved from just over 5 metres to over 7 metres full. While this is a great improvement we need to ensure stored water will sustain the town’s demand through until May if needed, which is typically when the Tamaki River flow is above its “low flow” level.

Pahiatua: Total Hosing Ban

Work continues at the infiltration gallery alongside the Mangatainoka River to ensure existing infrastructure can abstract required water volumes when the river is in low flows. While this has been impacted by rainfall and high flows, we are hoping the work can be completed over the coming week.

Recently there has been a significant reduction in water consumption, and Council would also like to thank the Pahiatua community for its conservation efforts. If consumption levels remain relatively consistent and works can be completed, we will be looking to remove the Total Hosing Ban in the coming weeks

Norsewood: Increasing to Alternate Evening Restrictions

Norsewood’s water consumption has remained high despite an increase to Alternate Days water level restrictions. We will therefore be increasing Norsewood’s restriction level to Alternate Evenings to try and bring down demand. Further restrictions may be necessary is current water consumptions level continue.

You can find handy ways to conserve water here: https://www.tararuadc.govt.nz/services/water-and-wastewater/water-conservation-tips

Woodville/Eketahuna/Akitio:

Residents should still be conservative and follow their respective restriction level.

8 February 2022

Firstly, we would like to say thank you to all the people saving water where they can.

We are hearing some fantastic stories of kiwi ingenuity being used to minimise water usage. Like this simple water recycling system one of our team has set up to water his garden. If you have water saving tips or a similar set up, please share it to our Facebook page.

Dannevirke’s water use over the past week has increased slightly, by around 1%. While this isn’t a lot, it shows conservation habits of some of our residents is slipping. We ask that everyone keeps water conservation at the front of their minds to reduce the risk of increasing water restriction levels.

The Dannevirke reservoir level is still decreasing and this, paired with the Tamaki river level dropping, means we really need to see a further reduction in usage to get us through the coming month/s.

We have some rain forecast, however this is not expected to be prolonged rain. We encourage residents to try and capture some water during rainfall for outdoor use.

Finally, thank you to those calling in potential leaks and potential breaches of restrictions which we are following up. We also have an exemption process in place which is assessed on a case by case basis. The form is available on our website or at our service centres.

The team at council are working extremely hard to get us through this challenging time and appreciate the support of the community.  Mayor Tracey and Chris Chapman, Group Manager - Infrastructure, are providing regular updates on Dannevirke Radio at 11am on Fridays where possible. Tune in to 107 FM. A big thank you to Radio Dannevirke for their support.


26 January 2022

Council would like to thank the community for the water conservation efforts to date and for their help in reporting leaks. Especially Dannevirke’s solid effort of saving around 2 million litres over the course of the week (around 6% of our towns weekly usage)! While this is great, it is necessary that the community, including extraordinary users, rally together to further reduce water usage.

While Dannevirke is the priority at present, water levels in rivers are reducing across the district so an increased focus on water conservation is important in all our towns. Norsewood, Woodville and Pahiatua will increase restriction levels.

Council would also like to draw attention to the similarities to summer of 2020, where rain was scarce and therefore our water supplies were stretched. During this time, our communities were a massive help with water management by conserving where they could. We are asking if our communities could again employ this community spirit and help us get through these summer months.

Pahiatua

Pahiatua’s water usage has been increasing rather than decreasing since December. Pahiatua’s water restriction level will therefore increase to Total Hosing Ban to try and kerb this high demand. Council is completing work at the intake point at the Mangatainoka River to improve the ability of the infrastructure to take the consented amount of water. In order to do this, we need the main reservoir to be full, as we will be unable to pull water from the river while these works are underway and will need to rely on storage, of which there are around 2 days. The reservoir is currently sitting at around 75% but needs to reach 100%.

Woodville

With minimal rain the Mangapapa River will soon reach low flows (below 24 litres per second). Under the current resource consent Council are not able to take water from the river at this point, meaning all water will come from the raw water reservoir. Under current water consumption levels (between 10-12 litres per second), stored water will last approximately 30 days. We expect summer will last longer than this, therefore Council are increasing the water restriction level to reduce water consumption. This will reduce this likelihood of further restrictions being applied, but only if water use reduces.

Dannevirke

We will provide a further update on the Dannevirke water supply later this week.

Norsewood

Norsewood’s water usage has steadily increased over recent weeks, to a point where it is not sustainable for the current bore. Therefore, Council will apply Alternate Day water restrictions and urge residents to please conserve water immediately.


12 January 2022

Further water restrictions in Dannevirke may be necessary

Council would like to thank the community for the water conservation efforts to date and for their help in reporting leaks. However, it is necessary that the community, including extraordinary users, rally together to further reduce water usage.

On 5th January 2022, Council was required to implement Total Outdoor Ban restrictions which led to some reduction in use. Without further water conservation in Dannevirke, Council will have to move from the current Total Outdoor Ban restrictions to an Essential Use Only restriction to prevent water from running out.

This means that water can only be able to be used for essential drinking, cooking and hygiene uses.

Dannevirke’s water is sourced from the Tamaki River and the water levels are dropping. Following recent dry weather, the river water flow has reduced to “low flows”, below 240 litres per second, which triggers a reduction in the rate of water Council can take. Council’s allowable take during “low flows” is less than the current daily usage for the town.

Typically, Council compensates in these circumstances by drawing water from the Dannevirke reservoir.  While this is now happening, Council has forecast this is not sustainable over summer as the reservoir was only able to be partly filled following the discovery of a leak that meant it had to be mostly emptied for urgent repairs.  The reservoir is approximately a third full at present.

Tararua District Council Mayor Tracey Collis says: “We would like to assure Dannevirke residents that there is enough water to go about the day to day activities of drinking, cooking, and personal hygiene. Other than this, we now need to come together in a collective effort to conserve water. Especially in Dannevirke, now is the time to rally together to adopt an ‘every drop counts’ approach and only use water when absolutely necessary. We’re starting to experience the impacts of climate change on our day to day lives, not only in Tararua but across New Zealand and the world. The conservation of water is being increasingly crucial to maintain our way of life. Water is becoming a scarce resource – let us work together to conserve it.”

As river levels are dropping throughout the region, Council is working closely with Horizons Regional Council to ensure water supply and is grateful for this support. Council has established a dedicated response team to manage this event to ensure security of water supplies in Dannevirke and the other towns in the district. We are also working closely with high water users to maximise the water savings available to them.  We are also looking to provide the community with water savings tips and ideas to ensure we collectively save every drop we can.

Under the current water restrictions, there will be a process to apply for extraordinary water use in which Council will consider exemptions, for example for businesses. Application forms will be made available at our service centres and on Council’s website. Given the seriousness of the current water situation, enforcement action may be required to be taken against those who do not adhere to the water restriction level.  The application form can be downloaded here. Please email it to info@tararuadc.govt.nz or drop into the nearest council service.

While Dannevirke is the priority at present, water levels in rivers are reducing across the district so an increased focus on water conservation is important in all our towns.

Pahiatua’s water restrictions:

Will move up a level to Alternate Night Restrictions, following reduced river levels and increased demand. This means hand-held hoses only on alternate evenings between 7pm - 9pm.

Woodville’s water restrictions:

Will be increasing to Alternate Days, now that the Mangapapa source is approaching low flows which require Council to stop taking any water.

Rain is forecast across the district for next week starting 17 January. This will help in the short term, however, is not expected to have a long-lasting effect.

Council will provide regular and continuing updates through the usual communication channels. We are very thankful to everybody for their efforts in conserving water, and for their patience, understanding and collaboration to help us maintain our water supply.


3 January 2022

Dannevirke's water restriction level is moving to Level 4 - Total Outdoor Ban, effective Wednesday 5 January 2022.

Following repairs to leaks, Tararua District Council (TDC) have been filling the impounded supply (raw water storage dam) when river levels allowed. Over recent months this has increased the depth of water from approximately 2 metres to nearly 8 metres. The water is 14 metres deep when full.

However, the Tamaki River is dropping and will soon enter low flows (less than 240 litres per second). At this point TDC will be restricted under a resource consent to take less water than Dannevirke is currently using – placing reliance on the water stored in the impounded supply.

It is likely that we are in for another hot and dry summer, with no guarantee on when the river will consistently be at higher flow, so TDC are implementing the increased water restriction to mitigate risks in late summer. While usage hasn’t been unusually high, it has still been higher than what TDC is allowed to take from the Tamaki River in low flow.

Chris Chapman, TDC’s Group Manager – Infrastructure, says “We have delayed increasing the restriction level until after the holiday break, but are now asking all users to play their part in reducing demand on Dannevirke’s water supply”.

TDC will also be progressing various initiatives to support water supply and demand management, in the meantime TDC needs the support of all users (through conservation) to prevent further issues later in summer and autumn – such as those during the 2019/20 summer. We appreciate that this will be frustrating for many and thank all for their understanding during this time.


21 December 2021

Council will be implementing Alternate Day restrictions to the Pahiatua water supply. This decision has been made as a precautionary measure after reviewing the extended forecast, which predicts long dry spells, and as Pahiatua’s water usage has increased over time. These dry periods could reduce the river level below where our infrastructure can take and therefore restrictions have been put in place.
Alternate Day Restrictions

Hand-held hoses only on alternate days, i.e. houses with even street numbers on even days and houses with odd street numbers on odd days.

Please note: Akitio water supply has increased to Total Outdoor Ban restrictions which is an annual water management activity.

This extended forecast also reinforces that water conservation is crucial over the summer months. With the increase in temperatures, Council is already seeing evidence of an increase in water usage to “beat the heat”. While this is expected during periods of hot weather, Council is asking residents to be mindful of their usage, reduce where possible and continue to adhere to the restriction levels in their town.

River levels and reservoirs are stable for now, however with extended dry spells forecast and if water usage trends continue as they are, Council may need to escalate water restrictions to the next level, a Total Outdoor Ban in Dannevirke.

As previously mentioned in our last update, Council has spent months inspecting and repairing Dannevirke’s impound supply after a leak was identified in July 2021.

During the inspection and repair period Council had to stop filling the impounded supply, with the purpose of confirming the height of any leak and reduce leakage. The identified damaged section had several splits, which was contributing significantly to the leakage. This section was removed and replaced, and the underlying protective layer was repaired to prevent future damage, before the cover was welded closed. Other areas in the reservoir were also inspected which meant further stoppages to filling the reservoir.

Due to this we have a comparatively reduced capacity coming into summer then we would normally. Therefore, from 1 December 2021, Dannevirke will head into Alternate Evening Restrictions (7pm – 9pm).

Alternate Evening Restrictions (7pm – 9pm).This means hand-held hoses only on alternate evenings between 7pm - 9pm i.e. houses with even street numbers on even nights and houses with odd street numbers on odd nights.

These increases are precautionary, and over recent weeks we have been filling the impounded supply with urgency. This has rapidly increased the height of water from ~2 metres to ~5 meters. There are some limitations when it comes to how fast we can refill due to our resource consent conditions and minimum river flows, as well as limits of our plant when it comes to taking water however our team are working hard to manage this as best we can.

While council works on its side to manage this, our residents can help us by conserving water where they can. The less water we send to town, the more we can send straight into the reservoir.

  • Make sure your tanks and swimming pools are full. Remember, covering your pool when not in use, can slash evaporation by 95 per cent.
  • Find and Fix Leaks. Finding and fixing leaking pipes around the house and your private property helps more then you may think. A single leaking bathroom tap can waste up to 33 litres each day!
  • Upgrading your appliances for Christmas. Retailers have the latest in water efficient appliances, meaning you can simply use less water by purchasing one which has an extra star on its water rating label.

More handy tips and even how to build a Rainwater Collection System


11 November 2021

Over the past four Months council and various suppliers have been investigating a leak in the Dannevirke impounded supply and providing our residents with updates when available.

Most Likely Cause

The unexpected effects of the 2020 drought is the best explanation for the leaks found at the Dannevirke impounded water supply.  The one in fifty plus year drought caused the ground to dry and contract which, when paired with the lowering reservoir level, exposed the plastic liner on the reservoir causing it to vibrate and wear until it finally failed from fatigue.  The splits found in the plastic liner allowed for water to start removing the protective clay layer below, exposing the liner to underlying stones which then increased the damage. Once the reservoir began refilling, only then did the leak become obvious, and water moving over the liner was able to be detected.

We still cannot say with 100% confidence the precise sequence of events leading to the major leak discovered to date, however we are taking the opportunity to assess various possibilities and prepare mitigation strategies to prevent a repeat situation.

Work Done to Repair this Issue

“With over 22,000 square metres of surface area, there has been a lot of area to assess. Initially it was like looking for a needle in a haystack.” said Council’s Group Manager – Infrastructure Chris Chapman.

Given that leaks of reservoirs with liners is rare, experts have had to come in from across the Country to investigate the source and points of the leak. We can now confidently say that our team has inspected all seams and points of suspicion.

Council also brought in an underwater drone on 2 separate occasions to assess the liner in the reservoir. With the first drone focusing on the bottom of the reservoir and assessing the “plug hole”, the point at the bottom which the water outlet is taken and fed to the treatment plant. There was no visible leak from this point. The second drone focused on the walls and liner, when the drone pointed up, we saw a tear in the cover and some small holes. We have now been able to expose this area for later repair as the weather again closed in for another fortnight.

Up to four tonnes of protective lime has been replaced and compacted below the liner covering the hillside metal that was exposed during the event.  In addition, an extra thick layer of geomembrane material has also been installed to mitigate this from reoccurring. In recent years, this extra layer has been considered best practice and was installed in the new Woodville water reservoir.

Next Steps

Since July, progress has been continually stalled due to poor weather. However, the impounded supply is now being filled and will be monitored closely for any further leakage. Improvements to monitoring devices on the cover (measuring the water depth) and at the drain discharge (measuring the flow of subsoil drain and possible leakage) are being completed.

We would like to thank everyone for their understanding and patience during this unprecedented event. We are still exploring ways to reduce pressure on our water supply without increasing restrictions for urban users. We are unsure what this looks like yet but will provide you with an update when we can.