Stream enhancement
Waterway restoration and protection work including riparian planting, habitat improvement, and erosion control
Consultation open
Stormwater is any water that falls on roofs, roads, paths and other hard surfaces. The water picks up contaminants from these surfaces and then flows via drains into local waterways. This affects the water quality and health of our streams, rivers, lakes and harbours.
Stormwater Management Plans outline how we can reduce contamination and progressively improve stormwater discharges. This Stormwater Management Plan is focussed on the 24 urban settlements of Banks Peninsula where there are stormwater networks. The Plan has two key purposes:
- To meet the targets under the Environment Canterbury Comprehensive Stormwater Network Discharge Consent for reducing stormwater contaminants.
- To describe the ways the health of waterways will be improved over time to meet environmental objectives.
Rural runoff including from roads is not included in this Stormwater Management Plan.
This is the last of seven draft stormwater management plans being prepared between 2020 and 2025 for the district’s different stormwater catchments.
Values
Water is a significant cultural resource that connects Ngāi Tahu to the landscape and the culture and traditions of their tūpuna (ancestors). All water originated from the separation of Ranginui (Sky Father) and Papatūānuku (Earth Mother) and their continuing tears for one another. Rain is believed to be the tears of Rangi for his beloved Papatūānuku, and mist is regarded as the tears of Papatūānuku grieving for Rangi.
From a Te Ao Māori worldview, water is a taonga (an invaluable treasure) given by ancestors to provide and sustain life. The taonga value not only refers to the water itself, but the resources living in the water, and the resources in the wider environment that are sustained by water.
Ngāi Tahu consider that their relationship with the waters of the rohe (region) has been eroded over the last 150 years. The current cultural health of the waterways and groundwater across the Waitaha (Canterbury) region is evidence that water management and governance in the takiwā (territories) has failed to protect freshwater resources. Surface and groundwater resources are over-allocated in many catchments and water quality is degraded by urban and rural land use. This has significant effects on the relationship of Ngāi Tahu to water, particularly with regard to mauri (life essence), mahinga kai, cultural wellbeing and indigenous biodiversity.
For tangata whenua, restoration of the cultural health of freshwater resources across the region is important for kaitiaki (guardians) in the present generation to ensure that the taonga is available for future generations.Rūnanga of Te Pātaka o Rākaihautū Banks Peninsula
Manawhenua represents the ability to influence and exercise control over a particular area, or region, and act as its kaitiaki. Manawhenua is derived from whakapapa (genealogy) and is protected and secured through continued occupation of ancestral lands (aki kā roa), the continued use of resources (mahinga kai) and the protection of the mauri of resources and the environment. There are five Papatipu Rūnanga who hold manawhenua across Te Pātaka o Rākaihautū Banks Peninsula: Ōnuku, Te Hapū o Ngāti Wheke, Te Rūnanga o Koukourarata, Wairewa and Taumutu.
Cultural Impact Assessment
Cultural health and mana whenua values monitoring is proposed to be undertaken to inform this Stormwater Management Plan. Mahaanui Kurataio Ltd is leading this monitoring, which will be undertaken in conjunction with Ōnuku Rūnanga, Te Hapū o Ngāti Wheke, Te Rūnanga o Koukourarata and Wairewa. Mahaanui Kurataio will prepare a Position Statement on behalf of Papatipu Rūnanga, based on the draft Stormwater Management Plan. It is not likely that the Position Statement will be ready until July. At that time you can download and read the Position Statement on our website.
Catchment
Te Pātaka o Rākaihautū Banks Peninsula lies on the eastern margin of the Canterbury Plains. The Stormwater Management Plan defined catchment area is east of the summit of the Port Hills and includes a triangle taking in Birdlings Flat and part of Te Waihora-Lake Ellesmere. The Stormwater Management Plan applies only within the catchment’s 27 settlements stormwater network. The rest of the catchment is mostly rural, and mostly in pastoral activities and open/conservation space. Urban zonings in settlements occupy 500 hectares in total.
Contaminants
Controlling the contaminants of stormwater
The most significant contaminants are Total Suspended Solids (TSS, mostly sediment), copper, and zinc. Click or tap below to learn more about where these contaminants come from:
Actions outside of what we’re proposing
Source control options such as painting or treating bare roofs or installing low-copper brake pads are the best means of keeping contaminants out of stormwater. Filters on downpipes are useful too. While these actions are desirable they’re not within the Council’s powers to require under the Local Government Act.
What we're proposing
We’re considering three options for physical works to achieve contaminant load reduction and improved overall waterway health. The selections were based on modelling, environmental drivers, tangata whenua values, and practicality. Each of the options includes a mix of stream enhancement measures, treatment devices and other actions.
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Treatment devices
Engineered systems — like filters or special units above or below ground — that clean stormwater before it flows into our rivers and streams.
Stream enhancement measures
Treatment devices
Other actions
- Stream enhancement measures to improve waterway health.
- Instream sediment remediation trial
- Treat stormwater from some busy urban areas in filtration devices.
- Stormwater from any significant new developments on Banks Peninsula would be managed with filtration devices.
- Erosion and sediment control on development and construction sites.
- Working with community groups and the public to educate the community about the effects of and how to mitigate stormwater contaminants.
- Collect and list future environmental improvement needs for consideration by the Council in future Long Term Plans.
- Collect and list potential flooding improvements for consideration by the Council in future Long Term Plans.
Actions outside of what we're proposing
Source control options such as painting or treating bare roofs or installing low-copper brake pads are the best means of keeping contaminants out of stormwater. Filters on downpipes are useful too. While these actions are desirable, they’re not within the Council’s powers to require under the Local Government Act.
Options we're considering
In our current budgets the Te Pātaka o Rākaihautū Banks Peninsula Stormwater Management Plan has been allocated $8.6m. Here are three options for how this budget could be used to address urban stormwater contaminants.
- Approx. 3 treatment devices ($1.6m)
- Stream enhancement ($7m)
- Approx. 12–14 treatment devices (est. $4.7m)
- Stream enhancement ($3.9m)
- Approx. 22 treatment devices ($8.6m)
- No stream enhancement
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OpenActivity closes 17/06/2025 at 11:59 PMWe will endeavour get back to you as soon as possible, however for more technical questions this may take a number of days to respond to.
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