10 Aug 2023
#INFRASTRUCTURE MATTERS
Downlands supplies 78,000 hectares within the Timaru, Waimate and Mackenzie districts and has several different sources and treatment plants.
Part of the scheme includes the Waitohi intake supplies the area north of the Opihi and Te Ana Wai.
The Waitohi upgrade is a part of the $26 million investment into the Downlands scheme since 2020. This funding includes replacement of aged pipework, new infiltration galleries, a new pump station, and new treated and raw water reservoirs. These upgrades represent the biggest investment into the Downlands water supply since the scheme’s inception in 1937.
Below is a timeline of the progress that has been done to the Waitohi intake at the Opihi River this year.
October 6, 2023
Downlands boil water notice has been lifted
The day has finally come where the final testing of the Downlands scheme on the Waitohi/Kakahu side of the Opihi River has been completed, and the boil water notice can be lifted.
A soft open of the new pipeline in the Opihi has been going on for a while and with multiple rounds of testing, and today, Council have been given the all go to lift the boil water notice.
The water that was supplied to the Waitohi residents before it was connected to the new Te Ana Wai water treatment plant recently did not comply with the new water standards. During the final stages of building the plant we had an unexpected pipe failure in an ecologically sensitive area, which meant we were unable to connect Waitohi residents to the new treatment plant until we could repair the pipe.
However, this has now been completed and is operational, which means the Te Ana Wai water treatment plant is now providing water to all its customers.
We understand this has been a long process and would like to thank you for your patience while we carried out these needed upgrades.
September 18, 2023
The operations, contractor, and water maintenance teams are on the commissioning plan as this will be a staged approach due to high pressures in the current main.
The team is hoping to complete final connections at Waitohi pump station side this week and will be getting ready for commissioning before the end of September 2023.
September 13, 2023
Good news, flushing of the new main commenced and successfully passed through the new main. After this, the team was able collect water samples which have now been sent to the lab for testing.
Last week, welding on the old main occurred and thrust walls were installed as well as a T connection for possible future upgrade options.
September 8, 2023
Good news, today a new connection spool is being welded to the old main.
All final connections and installations will be completed by next week and the main will be commissioned by mid-September 2023.
Our planting vegetation plan is currently being reviewed and planting will commence as soon as we have some new planting poles.
September 1, 2023
Waitohi Progress Update:
This week the team has reinstated all the stopbanks, and removed all of the excess tree stumps and rubble.
Currently the team is pressure testing the main, and chlorination will commence next week.
The project is still on track to be finished at end of September, 2023.
August 25, 2023
Waitohi Progress Update:
All pipe work is now completed in the river bed sections at the Waitohi pump station side.
The stop bank has been reinstated and the scour chamber has been installed.
The team is now trenching through the stop bank on the right side of the river which is going through a farmer's paddock to do the final pipe laying.
Pressure testing and chlorination will start next Thursday before the final connections are made to existing the structures. The remaining stop bank reinstatement will commence as well.
Connection work to the existing main will also start at the pump station side in the next two weeks.
The team is aiming to have the new pipe main connected and commissioned before the end of September, 2023.
August 21, 2023
Good news, all pipework across the Opihi river and the riparian has been completed.
The pipe assembly and excavations has started at the Waitohi pump station stopbank and pipes have been installed, as well as the scour valve.
Next week the team will begin excavations at the stopbank at Opihi Road. They will connect the existing main and then reinstate the river and the stopbank.
August 10, 2023
Waitohi Progress Update:
It has been a cold yet busy week for our construction and fish management team at the Opihi River.
On Monday, the construction team made sure the site was ready for the fish management team to set up the riparian zone (land along the river) next to the stopbank at Waitohi pump station side.
Fish trapping then commenced for two days.
Successful numbers were collected and removed from site, and were relocated outside of the construction work zone.Over 300 fish of all species were caught and relocated.
Tuesday afternoon the riparian was closed and dewatered, and more fish were caught and relocated.
Yesterday trenching begun so the team could start installing the blocks and begin backfilling today, which means they can have the riparian back by Friday afternoon.
Stopbank work will commence next week after reinstatement is completed between the trees.
August 2, 2023
Waitohi Progress Update:
Good news, trenching across the Opihi main river channel has been completed right up to where the tree line starts in the flood protection zone.
Backfilling and river reinstatement started this week to ensure works won't be at risk in the event of another flood.
Fish management will also start next week on the side creek, and construction will follow shortly after around the Waitohi pump station stopbank.
We are aiming to have the project completed by the end of August, and will be replanting the area in September.
July 13, 2023
Another quick update on Waitohi before the long weekend.
A 175m long water main will be installed into the riverbed today, while the riverbed will be reinstated to accommodate the river natural flow path.
On Monday, the team will start getting the river diversion back to its original alignment, and start some fish salvaging in the existing river diversion which was created for the contract works. This will take the team about 2-3 days to complete.
Fish salvaging involves collecting fish from where work is being done, and relocating the fish upstream or downstream of the works.
Rooney Earthmoving Limited will be starting construction on the Waitohi pump station side next week as well.
The project is on track!
June 16, 2023
Quick update on Waitohi before the weekend.
It's all go on site now as the settled (if a bit chilly) weather has allowed them to crack on with the works. The team are currently working to temporarily reroute the flow of the river away from the side we're working on.
This enables the team to put the trenching in place for the huge concrete blocks that the new pipe will run through. This will add significant resilience to the new pipe as we face more frequent high flow events.
Lots of work still do to, but they are making great progress.
May 16, 2023
Waitohi Update:
We're continuing to progress the project to replaces the pipeline under the Opihi River and connect Waitohi with the rest of Downlands.
Last week, our pre-ordered pipe arrived on site. Tenders for the construction work close soon and we’ll let you know once a contractor has been appointed.
We’ve also completed some maintenance and cleaning of the Waitohi treated water reservoir so it will be in top condition when we reconnect it to downlands.
April 28, 2023
Downlands: Waitohi update
Work on the major project to replace the pipe under the Opihi River and re-link Waitohi with the upgraded Downlands scheme is underway.
Now that the job is consented, pre-construction, site clearing and ground preparation works have started (pictured), including works required to protect native bats and birds.
The tender for the pipe construction work is currently open until mid may. The pipes required will be arriving next week.
Little bit of history:
The quality of water in the Waitohi scheme hasn't changed, there was a tightening of rules around protozoa, which the testing we had traditionally done didn't meet. Waitohi has its own intake and treatment plant as its main source, but had a connection to Downlands as a backup.
We had planned to use this connection and retire the Waitohi treatment plant but discovered a break in the pipe under the river. This is a highly ecologically sensitive area, home to many taonga species, so it was a complex and involved process to get the work consented.
This is all sorted now so the work can get underway. Once the new pipeline in in place we'll be supplying the township from the upgraded Te Ana Wai and can remove the boil water notice.
April 5, 2023
Waitohi Water Treatment Plan:
During the on-site ecological assessments to support the consenting process for our pipe replacement in the Ōpihi River, several protected species were identified as being present or likely present. These species included the Long-tailed bat, Black-fronted tern, Banded dotterel, Longfin eel, Torrentfish, Chinook salmon and Rainbow and Brown trout.
This caused us a significant delay of several months while we worked through the legal requirements to protect these species under the Resource Management Act 1991 and the Wildlife Act 1953.
In the last week, we have successfully obtained resource consents. This enables us to proceed with construction tendering. On-site preparations on the stopbank and adjacent land will commence from next week, to enable the pipe repair to commence in May.
The full pipe repair should take around two months to complete. We will be working with urgency to undertake our river works as quickly as possible as we have restrictions imposed on us regarding the timeframes we can work in the river. Once the pipe is repaired, Waitohi customers will receive water from the new Te Ana Wai treatment plant, and the boil water notice will be removed.