Rātana Pā Wastewater Treatment Project
A long-term project to improve the health of Lake Waipu by removing treated wastewater from the lake catchment and finding a sustainable wastewater solution for the future.
Status: Strategy being reassessed
Budget: Approved budget of $8 million. Forecast completion cost is currently $9 million, but this may change once investigations into alternative options are complete.
Timeline: Unknown due to reassessment.
The Rātana Pā Wastewater Treatment Project aims to improve the long-term health of Lake Waipu by changing how treated wastewater from the Rātana Pā wastewater treatment plant is managed.
At present, treated wastewater is discharged into a waterway that flows into Lake Waipu. The lake has high nutrient levels and is considered to be in poor ecological health. Improving the way wastewater is treated and discharged is an important step towards protecting this culturally and environmentally significant area for future generations.
The original project proposed upgrading the existing wastewater treatment plant, constructing a pipeline to transfer treated wastewater to a new storage pond, and irrigating it onto land near Whangaehu Beach Road instead of discharging it into the lake catchment.
Significant progress has already been made on this approach, including the purchase of suitable land, preparation of engineering designs, groundwater monitoring, irrigation planning and the lodgement of resource consent applications.
As the project progressed, however, a number of challenges emerged. These included increasingly complex consenting requirements, technical design issues, rising construction costs and changes to national wastewater standards.
Rather than continuing with a solution that may no longer provide the best value or long-term outcome, Council is reassessing the project to ensure the final investment is environmentally sustainable, financially responsible and capable of meeting future regulatory requirements.
As part of this review, Council is also investigating whether a broader wastewater solution involving both Rātana Pā and Koitiata could provide greater long-term certainty while reducing overall capital costs.
While this means the project will take longer to complete, reassessing the options now helps avoid investing millions of dollars into a solution that may not provide the best long-term outcome for the community or the environment.
What we've achieved
Council is now investigating whether a broader alternative strategy could deliver better certainty and lower capital cost.
The option currently being investigated would involve reticulating Koitiata and discharging treated wastewater from both Rātana and Koitiata through a sea outfall at Koitiata.
This option has not been confirmed as the preferred way forward. Council officers are still working through concept details, costs, feasibility, and potential impacts.
The next steps are to complete the Koitiata outfall concept investigation, talk with affected communities and stakeholders, and bring the information back to Council for a decision.
The Rātana Community Board was advised that other disposal options were being considered, and that changes to wastewater standards may support other options.
This marked a shift from simply progressing the original land-discharge option to considering whether another strategic option could better meet the project goals.
A hui with Rātana representatives was held on Wednesday 30 October 2024. This covered project costs, consenting and water reforms.
Council contractors, WSP, also met with two consent submitters. Submitters requested additional features, including a wetland and further pond improvements. Council officers considered these requests carefully, noting they could add complexity, cost and ongoing management requirements.
The original estimate and Long Term Plan budget of $2.425 million was no longer enough to deliver the project. A standard procurement estimate showed the project could cost about $11 million.
In September 2023, Council increased the total project budget to $6.532 million. This reflected post-COVID construction inflation, higher land values, more complex consenting requirements, and a longer pipeline than originally hoped.
At this stage, Council was still finalising its response to Horizons Regional Council’s section 92 request. Delays were caused by pond sizing and site-location issues.
Discussions with landowners about the pipeline route were also ongoing, and the pump station, pond, pipeline and irrigation design had not yet been finalised.
Land had been found and purchased.
Pipeline and irrigation design had started, treatment plant upgrades had been defined, and the resource consent application had been lodged.
Iwi support for the irrigation-to-land approach had also been reported.
At this stage, the project was still dependent on resource consent, easements, extra land purchase and final design.
The resource consent application was lodged with Horizons Regional Council in December 2022.
Horizons then issued a section 92 request seeking more technical information, including soil sampling and analysis.
This was a significant delay point. The final design could not be completed until the consent information and likely conditions were clearer.
The subdivision for the purchased land was finalised in November 2022.
At this stage, the resource consent application was expected to be lodged with Horizons Regional Council in early December 2022.
Once consent was approved and conditions were known, Council expected to finalise the irrigation design and move towards construction.
The project was focused on removing treated wastewater from the Lake Waipu catchment and discharging it to land.
The scope included land purchase, irrigation equipment and upgrades to the Rātana Pā wastewater treatment plant.
At this stage, the project budget was $2.425 million and the expected completion date was December 2023.
The 2020/21 Annual Plan and 2021-31 Long Term Plan included $1.55 million across project lines.
This included $875,000 granted to Council through Horizons Regional Council from Ministry for the Environment funding.
The project began on Monday 1 July 2018 through an agreement with the Ministry for the Environment.
It was established as a freshwater improvement project involving local iwi, Rangitīkei District Council, Horizons Regional Council and the Rātana community.
The original purpose of the project was to remove treated wastewater from the Lake Waipu catchment. Once the wastewater discharge is removed, Horizons Regional Council will be able to progress restoration planning for Lake Waipu, including planting and ongoing water-quality monitoring.