Area grade: A
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
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
The reporting area consists of Great Barrier Island and Little Barrier
Island which cover 320KM2 OF LAND representing 6.5% of the
the reporting area has the largest native vegetation (92%) of any of the
The extent of impervious surface (hard surfaces) is likely to be lower than
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 Great Barrier reporting area is predominantly forested and as a result
the health of the area’s rivers is likely to be excellent.
Rivers in this reporting area tend to have riparian margins with lots of
trees and bush, which provide shade, leaf litter and woody debris to the stream
and anchor the stream banks. The absence of urban development means there is
very little channel modification or pollution from discharges or
The data used to produce this report card is from:
|Native forest average*||||Water quality||2014-16|
|Kaiaraara Stream||DOC hut||SEV||2014|
|Kaitoke Creek||Hot Springs Track||SEV||2014|
|Karaka Bay Stream||Karaka Bay Road||SEV||2014|
|Mabey Stream||Mabey Road||SEV||2014|
|Rarohara Bay Stream||DOC reserve||SEV||2014|
|Tryphena Stream||Medland Road||SEV||2014|
* It is impossible to monitor every characteristic of every freshwater
environment, hence for some areas, such as Great Barrier, we monitor ecological
health but have used results from similar catchments to infer water