Horizons Regional Council
Kaikokopu Stream Revitalisation Project 2016
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.
London Street Watercourse Rehabilitation
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 makeover begins
In 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