The Auckland Council operates a long-term river water quality monitoring programme throughout the region. The objectives of this monitoring include state of the environment reporting, identification of major environmental issues and the assessment of the efficacy of council policy initiatives and strategies.

This report documents any changes to the monitoring programme and provides a summary of the data collected during 2014. Water quality is assessed monthly at 36 sites around the region using a combination of field based and laboratory tested parameters. The results are presented as box plots, which display the variation in the measured parameters at each of the sites, and in tables, which provide a statistical summary of each parameter at each of the sites. Water quality indices and classes were produced to show the complex water quality data in a simple form. In 2014 the rivers with the highest ranked water quality class were the Cascades Stream (Whakanewha) and Wairoa Tributary, followed by the Cascades Stream (Waitakere). These were the only three sites classified as having ‘excellent’ water quality in 2014. Poor water quality was observed in streams with a mix of urban and rural catchment land-use, with Omaru Creek having the lowest ranked water quality.

Auckland Council technical report, TR2015/028

November 2015