We carry out routine monitoring of river water quality under two main programmes:
This monitoring provides information on the condition of the water so that we can assess its suitability for uses (such as supporting healthy ecosystems or human recreation).
We have 10 sites on the Waikato River and 105 sites on other rivers and streams (including five NIWA sites).
Sites are grouped into two river reaches (upper and lower reaches of the Waikato River) and seven zones.
|River reaches and zones||Number of sites|
|Upper Waikato River||5|
|Lower Waikato River||5|
|Inflows to Lake Taupō||13|
|Upland tributaries of the Waikato River||12|
|Lowland tributaries of the Waikato River||26|
|Waipa River and tributaries||16|
The Waikato Regional Council began monitoring sites on the Waikato River between 1980 and 1987. The regional rivers programme started monitoring between 1993 and 1994. Monitoring started at the five NIWA regional rivers sites between 1989 and 1990.
We measure water quality by either taking measurements on site (for example, water temperature and water clarity) or taking samples of water back to the laboratory for analysis. We measure more than 20 water quality variables. They include:
Only the water clarity and microbiological data are used for this indicator.
The Waikato Regional Council has developed three categories of river water quality for contact recreation:
We based these categories on the ‘critical values’ for two water quality variables that are relevant to the suitability of river water for contact recreation. The variables are:
Check out the table below for critical values for the three categories that were derived from national or other standards and guidelines, and from expert opinion.
At each monitoring site, we determined the proportions of all samples collected during 2013-2017 for a given water quality variable which met the standard for excellent water quality. Similarly, we determined the proportions that met the standard for satisfactory and unsatisfactory water quality. This process was undertaken for both variables.
At each site, we calculated the average value of the proportions found to be ‘excellent’ for both of the variables. We also calculated the average proportions for the ‘satisfactory’ and ‘unsatisfactory’ categories.
We then aggregated the results for the individual sites according to site location. We also aggregated the results from the five Waikato River sites upstream of Lake Kāarapiro into an upper river result, and the other sites into a lower river result. The results for the other 105 sites were aggregated into seven water zones.
The table below lists the river water quality guidelines used.
|Water quality variable (units)||Relevance||Categories|
|Clarity, baseflow (m)||Visibility||>4||1.6 – 4||<1.6|
|Escherichia coli, 95th percentile||Human health||<55||55 – 550||>550|
Tulagi, A. 2017. Waikato River Water Quality Monitoring Programme: Data Report 2016. Waikato Regional Council Technical Report 2017/14. Waikato Regional Council, Hamilton.