New Zealand's National River Water Quality Network 1. Design and physico‐chemical characterisation

Abstract

The first 2 years of monthly‐sampled physico‐chemical data from 77 river and stream sites in New Zealand's National River Water Quality Network are summarised. The data for the major ions, pH, dissolved oxygen, conductivity, clarity, temperature, and NO₃‐N from the majority of sites are normally distributed. The data for flow, BOD₅, turbidity, absorption coefficients, and total and dissolved nutrients (except for NO₃‐N) from most sites are positively skewed. Combined data for all sites are compared with water quality standards and criteria, and “average” world freshwater concentrations. The vast majority of samples are well within accepted standards and criteria for a variety of river water uses and the waters can be classed as being of relatively low ionic strength.

Keywords:

• water quality
• statistics
• exploratory data analysis
• standards
• criteria
• network
• periphyton