Riparian management

Enhancing the effectiveness of riparian management along lowland Canterbury streams

The Ashburton-based Mackenzie Charitable Foundation was established 30 years ago by Donald and Alan Mackenzie, who farmed near the mid-Canterbury settlement of Hinds. After their deaths, their substantial farming property and assets became the property of the Foundation. The Foundation has granted UC $1.3 million over five years to fund a new professorial chair, Angus McIntosh, to oversee research into enhancing riparian management. The overall aim of this project is to enhance the effectiveness of riparian management and thereby to reduce the impacts of sediments and pollutants on Canterbury waterways. The research team will investigate the source and fate of nutrients and sediment entering both rural and urban streams. They will develop methods appropriate to streams of different sizes.

Canterbury’s waterways are home to many native invertebrates and fish, but they also play a vital role in the productivity of lowland farms. Often these values are seen as mutually exclusive with high-intensity farms
increasing sediment and nutrient input into streams and degrading their health. However, with effective riparian management, well managed streams can provide both water resources and a diverse and healthy environment for fish and other animals. Current riparian management tends to focus on larger waterways. However, some of the benefits of riparian plantings may be undone if smaller, impacted streams flow into these managed waterways. The effects and practicality of planted riparian zones are likely to vary with stream size, thus there is need for the development of a riparian management plan from the headwaters downstream that deals with specific problems associated with small streams. Appropriate management techniques must be developed in
consultation with farmers to both protect small streams and farmers use of the water. Thus the main research question is ‘How does the influence of riparian margins change with stream size and flow?’. The research will investigate whether it is possible to ‘engineer’ catchments to reduce runoff and enhance use of nutrients to reduce downstream impacts.

Small, unmanaged streams like this one may negate many of the benefits of riparian plantings downstream. Thus the proposed research will reveal how riparian management can be tailored to the size of the stream and to the needs of the farmer.

This research will be divided into three main components: (a) a spatially extensive survey, which will measure a wide range of riparian and in-stream factors to identify large-scale patterns and trends across Canterbury; (b) intensive case studies of a sub-set of streams (including lowland and urban), which will be investigated over the longer-term; and (c) a series of experiments, manipulations and trials will be conducted to further test patterns and mechanisms identified by the large-scale survey and intensive case studies

People involved in this project

University of Canterbury
Jon O'Brien
Angus McIntosh
Jon Harding

Missouri University of Science & Technology
Dev Niyogi