Healthy Streams

Kararo Stream project - artist's impression

Healthy Streams Whanganui is a community project led by Whanganui District Council to keep our waterways clean and tidy.

Community project partners include local iwi, Horizons Regional Council, government departments, charitable trusts, commercial businesses and landowners.

Several projects are underway or have been completed on streams around the Whanganui River.

The Whanganui Catchment streams included in the project include: Kokohuia (Rogers Street), Karamu (Churton Street), Tangingongoro (Russell Street), Kaikokopu (Kelvin Street), Zoo Creek (Aramoho), Tutaeika (Paterson Street East), Awarua (Nepia Road), Mateongaonga (Riverbank Road), Ngatarua (Putiki), Matarawa (Whanganui East) and Purua (Durie Hill). 

Karoro Stream rehabilitation

Whanganui District Council has partnered with GasNet to tidy up the watercourse at the end of Karoro Road in Gonville. This watercourse was probably one of the original estuary outlets for this catchment, but has been affected by intensified industrial and urban development in the surrounding area over many years.

As part of the project, we are renewing the gas mains and also lowering them so they do not cause an obstruction for flows during rain events.

We will also be planting more appropriate riparian type planting along the length of this watercourse.

Awarua Stream makeover – Wikitoria Road culvert

The Council is working with Horizons Regional Council on an enhancement initiative for a section downstream of the Wikitoria Road culvert, which will include some removal of alien plant species and revegetation with appropriate riparian-type planting. This work will be done in 2019.

Matipo Street watercourse rehabilitation

In 2017, the Council partnered with the Matipo Community Development Charitable Trust to revitalise the section of the watercourse at the end of Matipo Street. Local residents did the planting work as part of a training initiative through Land Based Training towards a qualification in horticulture.

Kaikokopu Stream revitalisation project

In early 2016, the Kaikokopu Stream was identified under the Healthy Streams Initiative as an area which required remediation in order to provide ecological, environmental and hydrological gains.

A project was initiated to revitalise a 700m section of the stream that traversed Council land.

Environmental solutions were implemented to provide ‘soft engineering’  solutions to manage any adverse effects. These environmental approaches included the decrease in the angle of bank slopes, scour protection through the use of eco-matting and grass resurfacing, planting a range of New Zealand native riparian plants, the construction of rock pools at strategic positions and the construction of a fish passage, to allow access through a culvert pipe. 

Since this project, the stream has performed better hydrologically, and future fish surveys will determine the effects on ecological conditions of the stream. We continue to monitor the stream’s condition and will consider further enhancements for inclusion in the Long Term Plan.

London Street watercourse rehabilitation

The London Street Watercourse Rehabilitation was initiated in late 2016 on 250m length between Glasgow Street and Victoria Avenue (beside the railway). Prior to the remediation works, the watercourse was clogged with invasive vegetation that slowed water flow and was an eyesore for those walking in the area.

This watercourse was targeted in order to provide a better hydrological, aesthetic and environmentally conscious situation. Environmental solutions were implemented to soften the look of retaining structures that were constructed on vulnerable slopes. To prevent erosion, eco-matting and grass was established on the steep slopes, and New Zealand native plants were planted among mulched product on the shallow slopes. During the course of the project, it was noted that a number of eels were living in the stream. This was quite surprising as the watercourse is only connected to the river through a network of stormwater pipes, with the most direct piped route exceeding 1.5km long.

Kaikokopu Stream: vertical brush walls

A section of the Kaikokopu Stream (between Somme Parade and Boyd Avenue) has had some sections of its banks strengthened, thanks to the Healthy Streams Whanganui project and funding from the Whanganui River Enhancement Trust (WRET).

The Kaikokopu Stream was eroding a section of Council land in Boyd Avenue, which may have caused an erosion risk to Somme Parade. To strengthen the embankments, two vertical brush walls have been created using a sterile dwarf willow species.

The roots of the dwarf willows will stabilise the embankment and the species will remain in place and not self-seed. The willows also release excess moisture from the embankment into the atmosphere and this reduces the weight of the earthen wall surrounding the bank. The vertical walls will allow the banks to maintain a steep angle – in this case the brush wall is 5.5m high.

Awarua Stream fish passage creation

Awarua Stream, in Pūtiki, is one of the streams in which is getting a makeover in the Healthy Streams project.

Part of the Awarua Stream makeover was completed in May 2014. Two fish passages were constructed, one at the crossing of Wikitoria Road and the other at the intersection of Nepia Road and State Highway 3. This work, thanks to funding from the Whanganui River Enhancement Trust, will make it easier for native freshwater fish to make their journey from the Awarua Stream to the Whanganui River.

Fish passages are created by adding rocks to the water flow to allow fish to navigate the stream and by lowering perched culverts (pipes) so fish can travel through the whole length of the stream.

The native plantings made by children from Te Kura Kaupapa Māori o Te Atihaunui-a-Pāpārangi, Whanganui District Council and Horizons Regional Council in November 2013. The trees are maturing and more plants have been added, thanks to Sustainable Coastlines.

Awarua Stream makeover

In November 2013, children from Te Kura Kaupapa Māori o Te Atihaunui-a-Pāpārangi joined staff from Whanganui District Council and Horizons Regional Council to plant native species around Awarua Stream in Nepia Road, Pūtiki.

The planting day was the first in a series of activities under the Healthy Streams Whanganui initiative.

The children planted appropriate species around the edges of streams to provides shade and create stable embankments, which helps maintain a natural flow pattern for the stream to make it easy for fish to swim to breeding areas. By following best practices for planting, the quality of the water is also improved as plants remove pollutants from streams, reduce silt and help to prevent erosion of natural water courses.

Here are some tips and advice about keeping waterways around the Whanganui District clean, tidy and as close to their natural state as possible.

Flood projection

In the winter, it is timely to remind those with streams running through their properties that minor maintenance can prevent flooding during heavy or prolonged rainfall.

If you have an urban stream on your property, here are a few useful tips:

  • Check streams and open drains for any obstructions – for example, fallen branches, rubbish or a heavy infestation of aquatic plants (most aquatic plants are easily removed by a garden rake and make excellent compost).
  • Consider planting native shrubs and grasses at the edge of your stream to create a favourable environment for aquatic life. Plantings should not be made in the stream bed or in the main channel of the stream.
  • Regular minor maintenance of your stream is easier and cheaper than major restoration works down the track.

How rubbish affects our streams

Did you know that when rubbish is left on the street or in public places, it washes up into the Whanganui River?

Discarded plastic, glass, shopping bags and even metal products eventually make their way into stormwater drainage, which flows to the river and eventually to the sea. From there, it can harm marine life and pollute water. New Zealanders throw away 3.6 million tonnes of rubbish each year and due to our close proximity to the coastline, a large amount of rubbish ends up in the sea if not disposed of appropriately.

There are several ways you can prevent this from happening:

  • Make sure all products which can be recycled (glass, cans, paper, plastic, oil) go to the Whanganui Resource Recovery Centre (79 Maria Place Extension) for proper disposal.
  • If you have family, friends or neighbours who want to recycle but can't get to the Centre, offer to do it for them.
  • Invest in a non-discardable water bottle which you can refill.
  • Use rubbish bins for other non-recyclable packaging rubbish.
  • Be a tidy Kiwi.

The life cycle of the eel

Did you know that native shortfin and longfin eels (tuna) live in the Whanganui River and surrounding estuaries and streams before travelling almost 3000km to deep sea trenches around the Pacific Islands to breed?

The adult eel usually dies at sea while their larvae drift back to urban waterways, developing into ‘glass eels’ (due to their transparent skin) and then ‘elvers’ (young eels). Elvers live in urban waterways for several years before starting the cycle all over again. Eels can live for up to 80 years!

Long lengths of pipe, raised culverts and shallow or polluted streams make it hard for the eels to complete their long journey. Improvements such as ‘fish ladders’ can be installed to allow elvers to swim safely.

If you have a stream in your back yard, you can make it easier for eels by:

  • encouraging the growth of native species around the stream to shade eel habitat
  • fencing off the stream from livestock to prevent stream erosion and pollution
  • creating fish ladders (there is lots of good information online)
  • encouraging your neighbours to follow your example.

Do you have a stream on your property or in your neighbourhood that you or a group want to improve?

Stormwater and freshwater experts at Whanganui District Council and Horizons Regional Council can help you assess the stream's current health and give you advice on actions and plans to improve stream health (including riparian planting and pest control).

They can also assist with getting resource consents and give guidance on how to get wider community involvement in your project and possible funding avenues.

The people to talk to are:

Or call the Whanganui District Council's Infrastructure Team on 06 349 0001 or Horizons Regional Council on 0508 800 800.