GDC held meetings in July last year with the Wainui Stream community over the best way to spend the monies and decided to conduct a study before moving further.
GDC shared services science manager Lois Easton, who presented the report, said there is a public perception the stream is healthy as it leads to a relatively pristine Wainui Beach.
Wainui Stream however is one of the city’s most degraded streams with high bacteria levels making it unsuitable for either contact recreation or stock drinking water.
The worst areas are the upper catchment at Heath Johnston Park, Murdoch Road and the Murphy Road area, mostly from dog faeces and grass clippings.
Problems faced by many urban streamsShe noted many other urban streams face similar problems.
“Dumping of dog faeces is a widespread problem in the city.”
There are also human sources present in the Heath Johnston Park area, particularly after heavy rain.
Ms Easton said the city’s wastewater system is “not all it could be” and further investigation into the sources of human sewage in the stream is continuing.
The report noted the significant effect of the Murphy Road culvert on water quality problems.
Tairawhiti Roads will be asked to look at how it can improve the culvert to allow better water flow during summer and to facilitate tidal flushing.
High water temperaturesLow water flows and poor shading, producing higher water temperatures, were other factors identified.
Naturally high sulphate levels, sourced from geological deposits in Sponge Bay, are the major source of “odour issues” upstream of the Murphy Road Culvert.
Ms Easton said the most effective use of the fine monies would be on measures at Heath Johnson Park, where the March 2015 sewage overflow occurred and where there is a large native eel population.
These measures include wetland and riparian planting, education signage at the park and Murphy Road beach entrances and an education programme.
Deputy mayor Rehette Stoltz commented a lot of people were probably not aware grass clippings were bad for the stream.
She was also amazed at the size of the catchment and said a lot of people would be unaware they were contributing to this problem.
A leaflet dropShe suggested a leaflet drop with basic information about the catchment area and the effects of garden waste and dog faeces.
Councillor Pat Seymour said the problem is also in other urban streams and suggested a wider effort to educate everyone about taking care of the city’s streams.
Councillor Andy Cranston raised concerns that during a discussion with Wainui residents about a proposed subdivision on the hill they were under the impression groundwater from the subdivison would be excluded from the Wainui Stream, yet the catchment map showed it would go there.
Kevin Strongman confirmed groundwater does go into Wainui Stream from the hill but is split into other areas as well.
The preferred options for spending the fine money will be presented to and discussed with the Wainui Stream community during a public meeting in early August before making a final recommendation at the September meeting of the committee.
