Determining High Priority Catchments – Water Quality Monitoring

River water quality is monitored as part of the Council’s State of the Environment monitoring programme.
Go to the State of the Environment Reporting - surface water monitoring page

This monitoring established that water quality was degraded or at risk of degradation in certain rivers. The pMEP identified these rivers and their catchments as priority areas to take action to enhance water quality.

Appeal Version - Policy - Chapter 15 - Resource Quality (Water, Air, Soil) (PDF, 967KB)

The state of water quality is reported using the CCME Water Quality Index. This summarises monthly measurements of several chemical and physical parameters to produce a score for the state of water quality in Marlborough’s rivers. This allows the overall state of water quality to be categorised.

For more information on how this is calculated go the State of the Environment Reporting - surface water monitoring page

The graphs below indicate the current water quality of Marlborough rivers.

5 October 2023 - Item 14 - State of the Environment River Health Monitoring Report 2023 (PDF, 8.3MB)

Water Quality Index

The blue bars on the left side on the graph below show the latest Water Quality Index for all rivers and streams monitored. The right side of the graph shows the contribution of individual parameters that cause a reduction in the Water Quality Index. The index allows categorisation of water quality into five different classes. The classes “fair”, “good” and “excellent” represent acceptable water quality, while water ways in the “marginal” and “poor” categories need to be improved where possible.

National Policy Statement (NPS-FM)

A new National Policy Statement for Freshwater Management (NPS-FM) came into force on 3 September 2020. The NPS-FM provides limits for 22 attributes, which define bands ranging from A to D/E. The A-band signifies healthy ecosystems, while states falling into the D and E-bands are generally designated as "below the national bottom line." Unless attributed to natural sources, states below the national bottom line are deemed unacceptable.

NPS-FM states for the 34 long-term river health monitoring sites.

*please note that the levels for Nitrate are based on toxicity, which are much higher than the levels required for nuisance algal growth. A waterway might have an A-band classification and still exceed the guidance levels for nuisance algal growth.