Infrastructure Projects
The CODC Infrastructure Department has projects on the go all over the district. From small sections of water pipe replacement, right through to large scale projects such as the Clyde wastewater reticulation. This page is designed to give you a snapshot of what we are doing and the positive outcomes for the community your council are seeking through these works.
If you would like to know more about any of the projects you see on this page, please contact us on (03) 440 0056 or water@codc.govt.nz where you will be directed to the correct team.
Below are updates on the projects for October 2022. For a pictorial update check out the Water Stimulus Project presentation (PDF, 18 MB) given to Council on Wednesday 6 July.
District Wide - Disruptions to Projects
As a result of the Covid-19 pandemic and the ongoing war in Ukraine, CODC is not in isolation in experiencing disruptions to the progress of our projects. These disruptions are being felt by the construction industry and infrastructure providers across New Zealand.
A number of factors are impacting the availability of design consultants, construction resources, scheduled timeframes and costs of materials, and labour. Our contractors are experiencing major delays in both international and local shipping of many key materials and components.
CODC is continuing to monitor this closely and working with its contractors to review project costs and timeframes at key stages.
Lake Dunstan Water Supply
Originally consulted on with the community in the 2018 Long-term Plan, the Lake Dunstan Water Supply project is taking shape. The $16.1 million upgrade to the water supplies of both Alexandra and Clyde recognise our focus on the health and wellbeing of our communities.
The project scope includes the expansion of the Clyde bore field and the construction of a membrane treatment plant and water storage tanks.
You might be aware of the benefit this upgrade will provide by reducing the lime in Alexandra’s water, but you may have questions about the membrane treatment. The membrane treatment provides an additional level of treatment, along with chlorination. The upgrade in treatment process will ensure we continue to provide safe drinking water to the community and we meet our responsibilities against the New Zealand Drinking Water Standards.
Progress through October
With all the different components that are involved in this project, the image below may provide an overview of the site as a whole.
The changes to the terrain involved with the water treatment upgrade add to the history of changes in the area to advance the community.
In comparison to the above, the two images below show how much the area has changed over the last 40 years.
The photographs taken in 1978 and 1981 respectively, indicate where our extended bore field now sits.
Photo from Thompson, R., 1991a. Clyde Power Project: Dam left abutment to Clyde groundwater. Letter report from DSIR Geology and Geophysics to Works Project Services, 14 May 1991. Taken by Homer (1978).
Photo from Thompson, R., 1991b. Item No.102, Foundation – Part 1, Excavation, Associated Remedial Work and Diversion Construction Report. Preliminary draft for comment. DSIR Report. Taken February (1981).
The site can be very busy with, at times, up to six different crews all working together towards the April 2023 commissioning date.
Three bores on the edge of Lake Dunstan will supply the treatment plant feeding Alexandra and Clyde. The installation of a new bore and the upgrade of a second, brings our borefield in line with new water safety regulations. The existing bore currently feeding Clyde will be upgraded once the treatment plant is commissioned in April 2023. The upgraded bores will be able to pump water to the raw water tank up to 160L/sec.
Our investment in the upgrade of our borefield ensures we provide safe, healthy and clean water to our community.
Left to right: Completed bore with new above ground design and flow meter. Upgrades to the second bore through September.
The unique design of the removable roof on the borefield building has paid off. The images below show the switchboard installation in September. Designing the building in this way meant that we could continue with the build while we waited for the switchboard to be constructed.
The unique design of the borefield building allowing for the roof to be removed for the installation of the switchboard in September.
Reliant Solutions completed the construction of the raw water tank on site at the end of August. The pre-treatment tank at 350m3 in size, allows for the control of flow through the membrane treatment plant.
Raw water tank at its full height end of August.
The construction of the treatment plant building is progressing well. The internal slab was completed in late August with the construction of the control room, chemical bund, staff amenities, loading bay and analyser room all completed within the last month.
The switchboard, weighing an impressive two tonne (that’s the equivalent of approximately 20 baby elephants!) was installed in mid-September.
The end of September saw the pouring of the plinths ready for the delivery of the three membrane racks due in late November. Throughout the planning and build, efficiency and resiliency have been kept front of mind. With predicted growth in the district, by 2028, it is expected that we will need to upgrade the number of membranes. In preparation for this, we have extra plinths ready to go.
Smart building and resiliency have continued through the construction with the installation of generators at both the treatment plant and the borefield. The generators will kick in within two minutes of any power outage, ensuring a reliable water supply, no matter what the conditions.
The roof, walls and roller doors have been constructed with insulation to ensure that we keep the equipment, and our people, warm in the winter and cool in the summer. To keep the electrical components cool through the heat of the summer, the team selected modern air-cooled scroll chiller units, for the high energy efficiency and sustainable benefits.
Top left – top right: July preparation for slab. Reo steel placed for slab to be poured
Bottom left- bottom right: Late August floor slab poured. Mid-September – installation of the membrane plinths and the switchboard.
June through to October saw the cladding of the exterior of the treatment plant building and the completion of the delivery bay ready for the arrival of the membranes.
Progress of the retaining wall along the south-western side of the treatment plant,
The pipe work and valves have been installed between the treatment plant and the treated water tank. Bypasses have been included throughout the site to allow for resiliency through any emergencies.
Mid-September – Pipework being installed between the treatment plant and the treated water tank.
If you travel between Clyde and Cromwell, you are likely to have noticed the green tank emerging from our construction site over the past month. The treated water tank has been constructed on site, starting in late September. The treated water tank holds 750m3 of water and feds Clyde and Alexandra. The tank is approximately 20m higher than the Alexandra Northern reservoir, so can fill the tank by 100% gravity with no pumping required – a great efficiency.
Room for second treated tank on the same site has been allowed as we plan for the future growth of the district.
Left to right: Construction of the treated water tank through September and October.
Alexandra Northern Reservoir
The construction of the reservoir will feed clean, safe water to Alexandra from the Lake Dunstan Water supply. Funded through Water Stimulus funding, the $2.8 million construction of the 4000m3 tank holds nearly enough water to fill two Olympic pools. The reservoir will be filled and commissioned when the Lake Dunstan Water supply project is completed in 2023
The reservoir will provide storage of treated drinking water for Alexandra for 10 hours during any periods of unplanned outages. We’re committed to improving the resilience of our local water so that everyone in our community benefits.
Progress through October
Fulton Hogan crews have completed the pipework that will connect the new reservoir tank to the main pipes laid at the bottom of the hill.
Reliant Solutions will be back on site through November to carry out leak testing. Leak testing consists of filling the tank to ensure there are no issues before the Lake Dunstan Water Supply go live date in April 2023.
During the construction of the new reservoir, resilience has been built in through the inclusion of valves to maintain flows through any required maintenance and an onsite generator for any unexpected power outages.
The unique construction of the tank can be seen in the time-lapse video capture by our contractor.
The new and old reservoirs.
Clyde Wastewater Reticulation Stage 1
A new reticulated wastewater system will replace Clyde's existing system which relies on septic tanks and disposal fields. The upgraded system will meet environmental and resource consent requirements, significantly improving the quality of Clyde's urban wastewater discharges.
Importantly, it will provide the Clyde community with an environmentally safe wastewater system that will bring significant environmental, health and well-being benefits for decades to come.
The project is being completed in three stages spanning from 2020 - 2043. Stage 1 involves connecting almost 200 properties many of which are in the Heritage precinct. The work includes installing main wastewater pipelines and two pump stations in Miners Lane and the Clyde Campground.
The image below, provide an overview of the recent work involved in this project.
We are on target to have all Stage 1 homeowners connected by Christmas 2022.
Installation of connections and low-pressure pump systems on private property.
Pump Station at Miners Lane completed
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If you would like more information on this project, check out the Clyde Projects - Central Otago District Council (codc.govt.nz) page and sign up for the E-newsletter.
Clyde Main Wastewater Pump Station
This $3.4 million project is a key component of the Clyde wastewater reticulation system. Clyde’s wastewater will be gravity feed from the township through two smaller pump stations before reaching this main pump station off Sunderland Street adjacent to the Clyde dog park. This pump station will then transport the waste through to Alexandra for treatment.
This project provides infrastructure to support growth and will contribute to improved water quality in the Clutha Mata-au.
Progress through October
Through the last week in October and early November the commissioning of the Clyde main wastewater pump station is being carried out.
The commissioning is a multi-stage process that systematically works through each process within the pump station to ensure correct operation before the go live date.
The commissioning included the installation and testing of the two pumps into the well. The pumps, at 55kw each, will work one at a time to pump the wastewater from Clyde to Alexandra at 69 litres per second. The well is 8m deep and 3m wide and will control the flow of wastewater from Clyde through the pipeline to the Alexandra wastewater treatment plant.
Other processes being tested through this phase of the project include the odour controlling chemical dosing unit, instrumentation and telemetry, connection with the Alexandra pump stations, the generator, valve operation, the operation of the emergency storage tanks, and the priming of the 8km wastewater pipeline from Clyde to Alexandra
The completion of the commissioning will allow for the final connections to be made to the properties and stage one of the wastewater system to go live.
Commissioning of the Clyde main wastewater pump station. Pumps being installed into the 6m deep wells.
Alexandra Wastewater Pump Station Upgrades
As part of your Council's commitment to reduce the environmental impacts from urban wastewater discharges, we are upgrading two wastewater pump stations in Alexandra. The first in the Linger and Die Reserve adjacent to Walton and Rivers Streets, with upgrades to the Dunorling Street station to follow.
Both projects include the connection of the Clyde wastewater reticulation system to the Alexandra treatment plant and increase the emergency storage capacity of each station. The emergency storage ensures that we have storage capacity within the stations during any unplanned outages.
Progress through October
At the Wrightsons Pump Station, which is in the Linger and Die Reserve, the Fulton Hogan team has installed the underground tanks and completed the welding and electrical work.
This was then backfilled and reinstated, the grass will be seeded in the upcoming warmer months.
The commissioning of the Clyde main pump station is closely linked with the Wrightsons Pump Station. Ensuring the two assets are synced with each other is an important step.
The storage tanks for the Dunnorling Street pump station upgrade have been ordered with delivery expected in early 2023.
Ensuring the protection of the flood bank and the restoration of the local area is an important part of all our projects. We gratefully thank the community and local residents for their understanding throughout this important project.
Pictured above the tank sections being craned in.
Clyde Falling Main Replacement - Completed
The completion of the renewal of the Clyde Falling Main through April and May was an important achievement.
Funded by the Central Government Water Stimulus package, the $1,050,000 project, replaced the existing gravity-pressured water main, a critical piece of infrastructure for the Clyde water network. The falling main supplies water from the reservoir, at the top of the hill, down to water mains at Sunderland Street.
The original falling main, constructed in 1987, was identified as having several issues that presented a risk to a resilient water supply in Clyde. The pipe material was identified as having poor seismic resilience and due to the steep terrain, effective maintenance and repair on the aging pipe was difficult.
This work will ensure that we continue to provide safe and reliable water to Clyde.
To create efficiencies across projects, three other pipelines were installed in conjunction with the falling main upgrade. Two pipes from the Lake Dunstan Water Supply and one from the Clyde Wastewater Reticulation project. We’ve invested our ratepayers' money effectively at the right time to ensure a positive outcome for the community.
