Darfield and Kirwee are two of the largest communities in New Zealand without a reticulated wastewater (sewerage) system. Currently, residents and businesses in Darfield and Kirwee manage their own wastewater, relying on septic tanks and on-site treatment plants.

men in high visibility jackets and hard hats support a black pipe as three diggers lower it into place across a road

The existing approach to wastewater discharges (on-site and to ground) has been identified as a potential risk to public health in the long-term and a limitation to growth of these communities.

To reduce any potential risk to human health or the environment, and to better provide for the ogoing population growth that both Darfield and Kirwee are experiencing, the Council is constructing a new wastewater system to service these townships.

This wastewater system will collect the sewerage from both Darfield and Kirwee townships, and pipe it to the existing Pines Wastewater Treatment Plant (WWTP) in Rolleston for treatment.

The project is part of the Council’s Long-Term Plan 2021-2031 and the Council successfully applied for $10.66 million of government funding for this project as part of the post COVID-19 Water Stimulus Package.

A stack of white pipesWhere is the pipeline going to be built?

The pipeline is 26.5km long and begins south of Darfield and ends at the Pines Wastewater Treatment Plant (WWTP) on Burnham School Road, Rolleston. A pipeline from Kirwee will also be constructed, connecting to the main trunk at the junction of Courtenay Road/Miles Road. The pipeline will be located within the road reserve (between the road and private property boundaries). The route is shown on the online project map below which shows the progress made.

Latest road works Summary

Current Closures:

all completion dates are approximate depending on weather

Project progress snapshot

Project update - 13 April 2022

Pipelaying has been continuing through March with the weather playing ball to keep good progress as we near the 80% of the pipeline being laid. We are expecting to see crews finish sections in areas shortly which will allow sections of road to be reinstated and reopened. The remaining 20% of the pipeline also involves some of the more specialised works as we cross busy highways and services over April.

Coming up these include

Pipe ramming to cross State Highway 1 and the Rail line at Aylesbury/Burnham Road intersection.

This method involves ramming a steel sleeve under ground before pulling through the pipeline. There are three lines to put in place at this point, one for Darfield to Pines WWTP and a water and wastewater line to cater for the District’s needs. Overall these works are expected to be completed in 9-10 weeks.

During this time there will be a one way system in place on Aylesbury and Burnham Roads.

Siphon Crossings under the Central Plains Water Line

The scheme crosses Central Plains Water lines in a number of locations and some of these require more complex works to do so. This involves installation of an inverted siphon and requires excavations up to 5m deep either side of the existing CPW line to complete. This is part of the works at Ansons Road works, between the Miles and Pole Road intersections, and requires a road closure to complete.

We appreciate these works are causing disruption to regular use of the roads and wish to thank road users in the district for following the traffic management in place. These measures are there to project yourselves and our site teams to safely and efficiently install the pipeline.

Check our road closures and detours map for the latest closures and detours.

Key facts and figures

  • 34L/s of flow with the current population of 4,373 people
  • >120L/s of flow is expected in the future when population is projected to exceed 13,000 people
  • 26.5km of pipeline to be laid
  • 54 manholes to be installed
  • 1000KPa of pressure that the pipeline is designed for
  • 2 pumpstations to be built
  • 8m the depth of the deepest excavation for the Darfield pumpstation
  • 6 pipeline sleeves to be installed below the state highways and rail lines using pipe ramming
  • 51 full time equivalent jobs directly involved in the project
  • 20,000 m3 of material being screened onsite and reused rather than imported from quarries
  • 6 work fronts are currently working across the project to install the pipeline
  • 114m the highest length of pipeline installed in a single day
  • 40,250 site hours completed
  • 26,500m of pipeline supplied

Frequently asked questions

How long will construction take?

The construction of the main pipeline to the Pines wastewater treatment plant is planned to begin in August 2021 and be completed by July 2022 for Darfield and August 2022 for Kirwee. To see the latest progress on the construction of the pipeline, check the map above.

Will my property be affected by the construction?

The Council and its contractors will maintain access to your property throughout these works but please contact us if you have any specific concerns.

There will be no disruption to your mail delivery or existing services, such as water, wastewater and storm water during the construction of the pipeline.

If your property is directly affected by works you can expect to receive a works notice from SDC’s contractor prior to starting.

Information on the latest road works for the project can be found below.

I have requirements for my home or business that I would like to know if they can be addressed

We are aware some of these roads are utilised for specific needs, such as moving stock or business access, and in most instances we expect to be able to accommodate specific needs.

Please contact us if you have any specific needs and wish to enquire how these will be addressed.

What’s the plan for properties connecting to the new pipeline?

The new pipeline will service both Darfield and Kirwee townships. Properties will connect to the pipeline in the following stages:

Stage 1 (starting August 2021): Complete the pipeline to the Pines wastewater treatment plant and require all new developments in Darfield and Kirwee to connect. Construct the sewer pipeline along the main street in Darfield in 2022/23, with businesses connecting from 2023/24.

Stage 2 (2021–2023): Together with Environment Canterbury, gather information on the current status of consented septic tanks. This will help inform the timing of the connection rollout. The Council will also review how the scheme should be funded.

Stage 3 (2025–2030): Construction of the local pipework to allow connections in higher risk areas of Darfield and Kirwee townships, such as areas with unconsented septic tanks.

Stage 4 (2031–2035): Construction of the local pipework to allow connections in lower risk areas of Darfield and Kirwee townships, such as areas with more recent consents for septic tanks.

When the project finishes work on my road how will it look?

SDC intends to reinstate areas that have been worked on to how they were before. For example, in areas where grass berms were trenched the contractors will shape the berm to return a similar profile, then remove large stones and wood that may be present, before seeding the berm. SDC’s contractors will also be using water carts to help the grass to strike quickly over the summer months.

If you have any concerns related to the reinstatement please get in contact with us.

History of the project

History and past reports

In the 2017/18 Annual Plan the Council signalled that a joint working party involving representatives from the Council, the Malvern Community Board, the Darfield and Kirwee Township Committees, Canterbury District Health Board and Environment Canterbury would further consider options for the possible establishment of a wastewater scheme for Darfield and Kirwee, which do not currently have a reticulated wastewater system.

The Council undertook a business case for the scheme, including consultation with Darfield and Kirwee residents in 2019.

Following this, the Council voted in February 2020 to progress work on a wastewater scheme for Darfield and Kirwee.

The Council agreed that there was sufficient evidence to support planning for a wastewater scheme in central Darfield. Further consultation on a possible system for central Darfield and developments in the township was part of the consultation for the 2020/21 Annual Plan. The Council confirmed it would continue to seek cost-effective and environmentally sound solutions for both the Darfield and Kirwee communities.

In December 2020 the Council was granted $10.66 million of funding from the Department of Internal Affairs for the project as part of the three waters infrastructure stimulus funding post-COVID-19.

In the Long-Term Plan 2021-2031 the Council included further consultation on the proposal for the wastewater scheme. In response to feedback from the public it agreed to continue with the proposal, constructing the scheme for all new developments and for the central business area in Darfield, and to review the costs and timeline for existing homes to connect to the to the scheme.

The following documents have been previously commissioned and are available for download.

A man in construction safety gear carries a pipe to two men in safety gear in a trench