Trends in river water quality in the Waikato region, 1991-2020

Report: IS 2021/16

Authors: Bill Vant

River water quality has been routinely monitored in the Waikato region since 1980. Monitoring at several Waikato River sites began then, with other sites being added later.

Vant and Wilson (1998) undertook the first comprehensive analysis of trends in water quality in Waikato Regional Council’s river monitoring programmes, examining records for the period ending in 1997. This was subsequently extended at 5-yearly intervals, covering the periods ending in 2002, 2007, 2012 and 2017 (e.g. Vant 2018).

This report describes a further extension of the analysis, covering the 30-year period 1991 to 2020.