Stormwater drainage

Three Waters Bylaw

The purpose of the Three Waters Bylaw is to:

• manage and protect the Council's water supply, Stormwater and Wastewater Networks from misuse or damage
• control and monitor Trade Waste Discharges into the Wastewater Network
• protect, promote and maintain public health and safety, and
• protect the environment

Three Waters Policy

The purpose of the Three Waters Policy is to provide additional information to the applicants and consumers who are required to work within the Bylaw.

Stormwater Drainage

Throughout the district there are certain stormwater and drainage systems being rated for. By looking after these specific drains and systems, Council wants to:

• Protect the public's health
• Ensure the public's safety
• Improve the natural water quality

Stormwater Management

Stormwater management refers to our commitment to manage the quantity and quality of stormwater through public drains. This includes stormwater flooding, erosion and sediment control and the Stormwater Management Bylaw (found under the Three Waters Bylaw).

Global Discharge Consent

The final notice of decision for the Amberley Global Discharge Consent was issued on 19 November 2014 by Environment Canterbury (ECan).

The application of the Global Discharge Consent for Hanmer Springs is under preparation and will be lodged with Environment Canterbury soon.

Stormwater Asset Management Plan

The purpose of Stormwater Asset Management Plan (AMP) is to ensure that the stormwater assets are operated and maintained in a sustainable and cost effective manner, so that they provide the required level of service for the present and future customers.

Township Weed Spraying Programme

Council Contractors carry out routine township weed spraying, including public drains every year. Sometimes they need to get onto private property to do this.

Public vs Private Drainage

The Council public drainage networks collects stormwater from each property, as well as stormwater that runs off roads and footpaths. This public drainage network is owned and maintained by Council.

When rain falls onto lawns, gardens, roofs, driveways and other hard standing areas within a private property, it is collected and drained through private drainage systems. This drainage system is owned by the property owner, and they are responsible for maintenance and upkeep.

Any stormwater problems within a property boundary are the responsibility of the property owner.

Key Components of Drainage

Some key components of drainage include:

• Driveway crossings and vegetated swales
• Overland flow paths and flood plains
• Water course and urban streams

On-site Stormwater Management Devices

On-site stormwater management devices include:

• Soakpits
• Retention tanks
• Rain tanks
• Soakage trenches
• Rain gardens
• Living roof
• Permeable surfaces

Manage a Stream

Plant natives

Plants can be attractive and help to increase native biodiversity and improve water quality. Native plants allow water to seep into the soils, decreasing the volume of surface water runoff and reducing the flood risk and pollutant discharge into natural drains.

Native plants can make a big difference to the stability of stream banks, as their roots hold the soil together. Planting the right variety of native plants around a stream also creates shade and enhances the stream habitat.

Planting of the drainage network is encouraged by the Council, but this needs to be approved. Some guidelines can be accessed elsewhere:

Keep it healthy and keep it safe

Here are some tips for keeping a stream healthy and safe:

• Slow down stream flow to prevent erosion by using well-sited rocks or logs
• Use wire fences to keep kids safe, whilst letting water runoff through
• Provide shaded areas, as cooler streams can support more natural eco-life
• Keep the stream free from garden waste and any fallen trees (blockages)
• Avoid overusing chemicals like fertilizers, herbicides, pesticides and insecticides near natural streams
• Ensure fences are an appropriate distance away from a natural drain
• Provide designed access for people and/or machinery
• Keep access way free of trees, hedges and other obstacles
• A bridge, rather than culvert, allows for more natural water flow
• Do not put buildings in known or identified floodplains

Stormwater and Your Home

As a landowner, you are responsible to manage the stormwater on your property. This includes managing potential flooding and environmental impacts.

Frequently Asked Questions

Some frequently asked stormwater questions are answered here.

Other resources and reading materials

• Flood protection & Drainage bylaw (ECan)
• Drain maintenance (ECan)
• Caring for urban streams (Auckland City Council)
• www.ecan.govt.nz
• www.ngaitahu.iwi.nz
• You can apply for funding assistance through the Environment Canterbury Biodiversity Fund for projects to enhance natural waterways.