What’s Council doing to ensure a resilient drinking water solution?

Published on November 11, 2022

Our community has been asking us what we’re doing to ensure a resilient drinking water solution is in place for Levin and Ōhau. While we’ve put significant effort into investigating the options available and have set aside budget within the Long Term Plan (LTP) for the work, we still have a long road ahead before concept moves to construction. 

Chief Executive Monique Davidson says “We’re hopeful and have put in a lot of groundwork to ensure we’ve considered what’s best for the river and subsequently what’s best for our community. There are some key milestones yet to be achieved, which means we can’t get ahead of ourselves. The consenting process is complex and could take several years, given the scale of the work proposed. Our iwi partners, who we have been working closely with, need to be confident that the proposed solution is the right one and key stakeholders such as Horizons Regional Council, the Department of Conservation and the New Zealand Fish and Game Council also need to be confident that the proposed solution is the best for the taiao and our community.”

Monique continues “As a Council, we need to do an exceptional job of helping our community understand the context, giving them the right information, asking for their input and listening to their views before a solution will go before Elected Members for adoption and the green light to invest a significant amount of money.

It’s important that our community understands that the challenge we face is not just constrained to water supply or storage. There is a shared responsibility to use water sustainably for both Council and the infrastructure we maintain, and for everyone in our community. So as part of the upcoming community consultation, there needs to be discussion and outcomes that see us valuing and using water in a more mindful way.”

So what is Council proposing and where are things at?

Background
The Levin and Ōhau drinking water supply is currently sourced directly from the Ōhau River at an intake site near the existing Water Treatment Plant (WTP) on Gladstone Road.

Post-treatment storage of approximately 12,000m³ is provided at the WTP site. This equates to less than 24 hours of supply (less than one day of current peak demand). The post-treatment storage does not provide sufficient storage to meet extended periods of drought or high turbidity (muddiness) in the river. Options to increase this are being considered in the short term and will be considered as part of the LTP Amendment.

The Water Supply Reservoir project seeks to construct a large scale off-river raw water reservoir to improve the resilience (during heavy rain events and dry weather periods) and reliability of the Levin and Ōhau drinking water supply scheme and to provide sufficient water to meet the projected growth demands for Levin and Ōhau. 

Following concept design and a multi-criteria analysis, a single reservoir was selected as the preferred option primarily due to cost considerations and the fact that the  embankment required to separate the site into two reservoirs results in a significant loss of stored volume. The storage volume of a single reservoir is in the order of 700,000m³.

What’s been investigated so far?  

• Council has completed a feasibility assessment, which confirmed the feasibility of the reservoir site on Poads Road, Levin for construction. 
• Council also completed an options assessment, reviewing the water supply and storage options available, to ensure the option chosen is the right one. This assessment has been independently peer reviewed.
• Iwi engagement has commenced and will continue through the project delivery, should the project and investment be adopted as part of the LTP Amendment.
• A hydrology assessment is in progress and will continue with technical assessments to support the consenting and design processes. Work to date has confirmed availability of sufficient water in the supplementary allocation framework to support the projected community demand.
• A feasibility assessment  saw three intake options assessed. This work identified the preferred intake as a subsurface infiltration gallery in the Ōhau river adjacent to the reservoir site.
• An ecological assessment has been completed of the reservoir site. This confirmed there were no wetland habitats, sensitive environments or threatened or endangered species within the reservoir site.
• An archaeological assessment is in progress.
• Preliminary design is in progress with the design being developed to sufficient detail to support consenting and costings.
• Consents scoping is in progress, but given the scale and complexity of the project, we’re working through the options available.

Elected Members will attend a series of workshops that began on Wednesday 9 November, to bring them up to speed with everything from our key strategic documents and how they inform work, to key topics like Three Waters, the Future of the Levin Landfill and Rates Affordability.

Shortly we will begin to do the same with our community, to help them understand the key challenges facing our district, the magnitude of decisions required and how they can have their say.  Our community can attend the Council Workshops, but from now until May 2023 they will see, hear and be able to participate in the LTP process.