GIS techniques for developing a habitat classification for rivers

Under the Resource Management Act (1991) water managers are required to promote the sustainable management of natural resources, which involves safeguarding the life supporting capacity of water and ecosystems. To help water managers give practical effect to the concept of life supporting capacity, the Ministry for the Environment (MfE) and a number of regional councils are working collaboratively to develop a system of habitat classification for rivers. This system forms part of the Environmental Performance Indicators (EPI) program and aims to be a tool for planning also. Habitat classification involves sub-dividing river systems into units based on the similarities and differences in a range of physical variables. The underlying principle is that the physical variables chosen determine the habitat and hence the bio-physical attributes of specific parts of rivers. Such systems are extremely useful tools for integrated water resource management as they assist with developing spatially explicit management objectives and setting environmental criteria. This paper presents a physically based river habitat classification system and describes the Geographical Information Systems (GIS) techniques implemented to provide data for this framework.