Skip to main content
Auckland Council

Freshwater report card, Waiheke reporting area 2016

Area grade: B​

What makes up this grade?

The overall grade is made up of five indicators:

Water quality: Water samples are tested for temperature, oxygen concentration, turbidity and the levels of pH, ammonia and nutrients (nitrogen and phosphorus). The results of this testing are compared against guidelines for Auckland to produce a water quality index.

Flow patterns: This involves monitoring the hydrologic connectivity of the river to upstream and downstream reaches and the floodplain using the Stream Ecological Valuation (SEV), which is a method of assessing the ecological health of our rivers.

Nutrient cycling: This involves monitoring the inputs and processing of minerals, particulates and contaminants using the SEV biogeochemical functions.

Habitat quality: This involves monitoring the diversity and quality of habitats using the
SEV habitat provision functions.

Biodiversity: Field assessments and samples are collected to assess the type and amount of native plants and animals using the SEV biodiversity functions.

Quick facts

  • The reporting area covers 155KM2 representing  3.2% of the region - the ninth largest reporting area
  • Land cover is a mix of pastoral vegetation (46%) AND native vegetation (45%)
  • The extent of impervious surface (hard surfaces) is LOW (7%) when compared with the regional average of 9%

Monitoring background and interpretation

Auckland Council’s State of the Environment (SoE) monitoring programme has been building a record of Auckland’s environment for more than 25 years. This information is critical to the effective management of Auckland’s natural environment, after all, you can’t manage what you don’t monitor.

The monitoring programme shows there is a strong relationship between the health of rivers and the type of land cover in the surrounding catchment. Rivers that drain through forested catchments (particularly native forests) typically have excellent water quality and ecology, while rivers that drain from urban catchments typically have poor water quality and ecology.

The Waiheke reporting area is predominantly pastoral, but with large forested areas still remaining. As a result, the health of the area’s rivers is considered to be good. Rivers in this area tend to have riparian margins with some trees and bush, which provide shade, leaf litter and woody debris to the stream and anchor the stream banks. The debris enhances the quality of habitat for flora and fauna, although some of the original riparian vegetation has been removed to allow more intensive land use. The low level of urban development means there is little channel modification or pollution from discharges or stormwater, although there may be diffuse sources of contaminants from the pastoral land use and physical damage from stock access.

The data used to produce this report card is from:

​River name​Site location​Measurements​Date range
​Rural average*​Water quality​2013-2015
​Home Bay Stream​Motutapu Island​SEV​2014
​Cascades Stream​Whakenawha Regional Park​SEV​2014
​Onetangi Stream​Forest and Bird Reserve​SEV​2014

*    It is impossible to monitor every characteristic of every freshwater environment, hence for some areas, such as Waiheke, we monitor ecological health but have used results from similar catchments to infer water quality.