The Big Stormwater Story

Information regarding residential zoning in flood prone areas is available in the District Plan on the Council website. Submissions regarding our District Plan are currently closed; however, if you have feedback regarding residential zoning, please email districtplan@chbdc.govt.nz or phone 06 857 8060.

The urban drainage network is mostly controlled by Council and drains on private rural land are the responsibility of the landowner to maintain. If an informal drain or ponding area is present on your property, it is under your ownership and management. We have a register of drains and flow paths across the district and are working on improving our policies and mapping private and public drainage to provide greater clarity.

Council’s stormwater management extends to Council assets only, which you can view on this map. Drainage issues that are unrelated to Council assets are generally the responsibility of private landowners to remediate.

To improve the performance of your stormwater drains:
• be aware of flow paths through your property; look at ground levels and observe how water flows during rain events.
• remove obstructions to flow; obstructions can gather debris, blocking the drainage channel.
• direct flows away from buildings and structures.
• look at your downpipes; if they discharge onto the ground, consider whether you want stormwater in that location.
• talk to the experts! Local drainlayers are essential when dealing with drainage issues.

To learn how you can actively manage contaminants on your property and prevent blockages in our stormwater network, read Council's practice note on our website. For those not connected to the Council's stormwater network, you can apply to connect to a Council asset nearby using this form.

Alteration or blockage of the stormwater network is prohibited by the Stormwater Bylaw 2021 and can restrict flow to the network. These are primarily caused by stock fences, which can trap debris and is especially problematic when willow saplings establish in the stream, blocking flow. If you see a blockage, please report it to Council by using the Snap, Send Solve app or calling Customer Service on 06 857 8060. Where restrictions and blockages are present, Council is enforcing under the provisions of the stormwater bylaw.

We have heard your concerns around litter and green waste in our drains and are working with perpetrators to stop the practice. Community reporting is one of the main ways we identify stormwater contamination so please continue to report litter and liquid waste in stormwater by phoning Council Customer Service on 06 857 8060. Thank you for your mahi!

We have developed an initial draft maintenance plan that outlines the frequency and extent of open and piped drain maintenance. We continue to refine this plan with key stakeholders and aim to finalise this within existing budgets in October 2023.

Council and our consultant partners have developed a maintenance plan outlining the frequency and extent of open drain maintenance required, which includes recommendations for best practice maintenance. We are currently finalising funding to implement this plan for the 2024/25 financial year, to lift the level of service provided to our community.

To ensure stormwater flows do not exceed predevelopment levels, we use hydraulic analysis of the site and risk mitigations such as tanks and ponds. We also assess the disposal method for effects to neighbouring properties, and protect existing watercourses and overland flow paths as required. We also collect financial development contributions that can be used for public-side services such as stormwater.

Addressing the flood risk for our stormwater systems requires a holistic approach. Some of the factors affecting flooding can be addressed more easily than others. Our technical advisers have identified those projects that will provide the greatest flood risk mitigation most easily in the short term, and these will be carried out as part of Phase 1.

The longer-term, high-value work to be addressed as part of Phase 2 will take the same holistic approach and address all the flood risks factors.

Corrective maintenance addresses those open drains where maintenance has been deferred or not carried out. These typically require intensive works to return them to their original design dimensions and performance. Most of Council's stormwater work since Cyclone Gabrielle in February 2023 has been corrective works. We have been focused on critical channels and can now extend this maintenance to some smaller drains that act as conduits or tributaries to the main drainage channel.

This refers to the day-to-day maintenance of the drain and is intended to keep the drain functioning as per its design parameters. Beginning in the new financial year, routine maintenance will be implemented in Waipawa and Waipukurau, with regularly scheduled vegetation clearance and excavation in open channels. The frequency of works will be dependent on the criticality of the drain.

Council and our consultant partners have developed a programme of easily implemented performance improvements to the network and are currently actioning the recommendations. The programme includes bank stabilisation, pipe upsizing, flap valve investigation and stream restoration. This programme is planned to continue over the next few years, subject to the finalised stormwater strategy.