Healthy Streams

Contents

​​​​​​​​​​​​​​​Healthy Streams Whanganui logo​The Healthy Streams Whanganui is a community project led by the Whanganui District Council in partnership with local Iwi, Horizons Regional Council, government departments, charitable trusts, commercial businesses and landowners. 

The aim of the project is to keep waterways in our district clean. Several projects have been undertaken on streams around the Whanganui River. Watch this space for more information.​

The streams  in the Whanganui Catchment area which are included in the Healthy Streams project are: 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).  You can see them on the map below.

Download the Healthy Streams Whanganui brochure. (758KB)

Whanganui Catchment Areas

Artist's drawing of Whanganui catchment areas 

Current Projects

Kaikokopu Stream Revitalisation Project 20​16

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 Whanganui District 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. 

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 ‘eye sore’ 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 amongst 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.

Whanganui District Council Senior Stormwater Engineer Kritzo Venter said the Council considered building retaining walls to prevent the erosion but found they were too expensive.

“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 and in this case the brush wall is 5.5 metres high.”

Mr Venter says vertical planting is an example of how environmental resources can be used as a solution to an engineering problem.

“As well as strengthen the banks, the willow planting helps the Kaikokopu Stream retain its natural flow which makes it easier for the stream to connect with the Whanganui River and ocean. This helps create a healthier habitat for native fish species to travel to and from their preferred breeding grounds.”

WRET is a charitable trust which promotes and encourages the enhancement of the quality of the waters and catchments of the Whanganui River.
 

Awarua Stream fish passage creation

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

The next step in 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 Maori O Te Atihaunui-A-Paparangi and Whanganui District Council and Horizons Regional Council in November 2013 are slowly maturing and more plants have been added, thanks to Sustainable Coastlines.​

Awarua Stream makeover begins

Children from Te Kura Kaupapa Maori O Te Atihaunui-A-Paparangi help plant native species around Awarua StreamIn November 2013, children from Te Kura Kaupapa Maori O Te Atihaunui-A-Paparangi (pictured) joined staff from Whanganui District Council and Horizons Regional Council to plant native species around Awarua Stream in Nepia Road, Putiki.

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.

Whanganui District Council Senior Stormwater Engineer Kritzo Venter said the children (aged 10-13) had a great day and he is looking forward to more activities which will get the community ​

Page reviewed: 03 Feb 2017 4:05pm