Mangakootukutuku Integrated Catchment Management Plan

Hamilton City Council is preparing an Integrated Catchment Management Plan (ICMP) for the  Mangakootukutuku Catchment.

​It’s important that as urban development occurs, potential impacts are understood and there is a clear plan of what infrastructure is required to enable and support growth. ICMP’s outline how stormwater, wastewater and water will be managed in different catchments, with a particular focus on stormwater. They help Council make better decisions about land-use, water resources and infrastructure. 

Each catchment is unique and requires investigation to understand how stormwater flows through the catchment and what requires protection in the receiving environment (gullies, streams and lakes).​

Mangakootukutuku ICMP FAQs​

What is an ICMP?

The purpose of an ICMP is to outline how the Council manages water supplies, wastewater and stormwater in a particular catchment. It recommends improvements in areas that have already been built, and plans infrastructure for areas where future developments will be built.

Stormwater is the main focus of an ICMP, although wastewater and water supplies are also managed through ICMPs.

ICMPs give guidance on issues including:​

  1. Pipes and infrastructure.
  2. Requirements on new development or subdivisions to manage water supplies, wastewater and stormwater.
  3. Managing streams and waterways, including identifying problems like stream erosion and coming up with projects to help fix these problems.
  4. Identifying flooding issues and options to reduce flooding.
  5. Restorations and environmental projects.

Why do we have to treat and manage stormwater?

Storm water is often thought of as clean, but when it comes into contact with other surfaces it can collect contaminants such as sediment, phosphorus, copper and zinc. These contaminants flow into waterways (such as streams and lakes) and can create poor water quality environments for our native fish, wild life and plant life.  

When rain falls on hard surfaces such as paths, roads and roofs, it can’t sink into the ground. Instead it flows quickly downstream into gutters, pipes and streams. In some cases, where there is too much stormwater, this can cause flooding. Fast flowing water can also cause erosion and scour.​

What important stormwater features are in the catchment?

The Mangakotukutuku stream is the major stormwater network feature in the catchment. Many parts of the stream have high ecological value (eg. habitat for nationally at risk species including longfin eel, giant kokopu and inanga). Ecological restoration work has been carried out by different groups in parts of the stream.​

How do we treat stormwater?

There are many ways to treat stormwater to remove contaminants and reduce its speed before it gets into our waterways. These include encouraging more public and private green spaces, and building stormwater treatment devices such as wetlands and raingardens. Treatment can also include collecting rainfall and slowly releasing it or even re-using it so pipes and streams do not become overwhelmed with stormwater.​

What is a treatment system (train)?

Sometimes it will take several devices to remove certain contaminants and manage the volume of water.  A treatment train is made up of a number of individual treatment devices. Water flows from one device into the next, with the goal of removing a higher percentage of contamination than a single device could achieve.  A treatment train can be on private or public property. ​

Who maintains treatment devices?

Treatment devices located on private property such as rain tanks and rain gardens are required to be maintained by the property owner. Treatment devices that have been assigned to the Council, such as wetlands, will be maintained by the Council after a contractor or developer maintenance period.  

If you require more information or would like to provide feedback, email or phone 07 838 6903.​

Page reviewed: 05 May 2020 4:18pm