River Water Quality Reports

This section contains State of the Environment reports for River Water Quality. The most recent report was published in 2015.

Overview

This is the third five-yearly report on river water quality released since monitoring began in 2000. It contains detailed information on the condition and trend of river water using a range of chemical, physical, microbial and ecological indicators.

River water quality information from our core “State of the Environment” monitoring sites, national river water quality network sites as well as special investigations conducted by Council and external organisations are used in the report.

Results consistent with earlier reports

Results are consistent with earlier reports showing that streams draining intensively developed land were in poorer condition than sites draining undeveloped areas. In particular, sites classified as having pastoral or urban land cover had higher concentrations of nutrients, disease-causing organisms, and deposited fine sediments than sites with indigenous forest or exotic forest land cover. The main findings were:

  • About 40% of sites influenced by pastoral land use did not meet the national bottom line for secondary contact (activities without full body contact with the water such as boating or fishing).
  • Across all streams, nitrate and ammonia concentrations were well below toxicity levels for stream life. In several streams however, particularly spring-fed and lowland streams in the Waimea and Takaka areas, nitrate concentrations are high enough to fuel undesirable growth (filamentous green algae).

Trends

The major positive trends identified in the report are:

  • Significant improvement in water clarity at nine sites, including the upper Reservoir Creek, Sherry, Onahau, Onekaka, Mangles (2), Motueka (2) and Buller rivers
  • Reduction in disease-causing organisms particularly in the Sherry, Little Sydney and Motupipi rivers, but also at Wairoa, Wangapeka and Motupiko.
  • Very low levels of E.coli in the Aorere River and most of Tasman’s major rivers
  • Dramatic reduction in dissolved reactive phosphorus (which can encourage the growth of nuisance algae) in the Motupipi River

In addition, big improvements in abundance and diversity of fish and invertebrates are expected over the next 10 years in Richmond’s lower Borck Creek as a result of one of the largest stream restoration projects the Council has undertaken.

The Council recognises there is still work to be done to improve water quality in some places.

Some of the challenges that remain are:

  • Small streams surrounded by pastoral land often have high temperatures, low dissolved oxygen, heavy sediment deposits and poor habitat lack of streamside trees
  • Urban streams contaminated by run-off from roads, roofs and other pollutants
  • High levels of green algae in spring-fed streams in the Waimea and Takaka areas

The solution to many of the problems that remain is likely to be targeted streamside planting, which effectively addresses problems with dissolved oxygen levels (essential for the survival of fish and other aquatic life), water temperature, habitat removal and fine sediment trapping by aquatic plants.

Map

The map below links to the State of the Environment River Quality reports for each of the five main catchment areas.


Aorere Water Management Area

Buller Water Management Area

Motueka Water Management Area

Takaka Water Management Area

Waimea Water Management Area


This section contains the 2015 State of the Environment report for River Water Quality.

Related Links