My Account
A group dedicated to restoring and maintaining healthy waters in the Matakana-Sandspit catchment area have painted a cautiously encouraging picture of the state of local waterways, in the wake of a damning report on the condition of waterways nationally.
Last month, the Ministry for the Environment and Stats NZ released Our Freshwater 2020, which noted a huge decline in New Zealand’s freshwater eco-systems due to pollution from farming and urban development, changing waterways from their natural course and the inadvertent introduction of exotic species.
The report drew attention to a 2017 study which showed that 76 per cent of native freshwater fish were threatened with extinction.
But Friends of Awa Matakanakana (FOAM) says it’s monitoring of waterways gives some grounds for local optimism.
For example, monitoring of macroinvertebrates (creatures other than fish) using the Wai Care Invertebrate Monitoring Protocol (WIMP) consistently reveals scores greater than 100 – indicating a healthy river for macroinverebrates at the time of sampling.
No FOAM testing site consistently recorded a score of less than 70 – which would indicate underlying water quality problems.
However, FOAM vice-chair Martin Evans says the group recently started conducting bacterial testing to assess the level of animal waste discharges into local rivers and found two locations where there were exceptionally high bacterial levels.
“We need more testing and possibly contaminant source tracking – with Council assistance – before we can reach any conclusions,” he says.
FOAM has also noted elevated phosphorus levels in parts of the rivers, which could come from fertilizer use on farms or in horticulture, but could also be due to natural sediment erosion.
“We have not found any significant nitrogen, but have recently changed to using a more sensitive test and are starting to detect more,” Mr Evans says.
He says based on limited testing to date, rivers and streams are showing some signs of land use runoff impacts, although it does not appear to be severe at present.
Mr Evans says unfortunately there is currently extremely limited technical information on the catchments, which handicaps FOAM’s ability to make targeted assessments to determine the possible source of sediments and the best options for community involvement in riparian planting and other initiatives.
Things could be improved with a Council catchment management plan, such as one being developed for the Kaipara, which provides detailed information about the rivers, their ecosytems and developments across the catchment.
To learn more about FOAM, email matakanakana2@gmail.com
