Catchment hydrology and the stream environment

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Stream temperature is one of the most important physical factors influencing aquatic ecosystems. It directly controls species distribution, as well as rates of biological, biochemical and chemical processes. Stream temperatures reflect the interacting effects of meteorological and hydrologic processes, and stream temperature patterns can be influenced by land use and climatic variability and change. Much previous research has focused on the meteorological controls on stream temperature, but recent studies have shown that hydrologic processes are important. The objective of this research is to improve our understanding of the hydrologic controls on stream temperature to provide a more complete basis for predicting the effects of future climate change, land use and glacier recession. Field studies will  use a heat budget approach to examine the roles of water exchanges across the stream bed and banks in steep headwater streams in logged and unlogged areas to evaluate their importance relative to other processes. In addition, the effects of pools, which are common features in small, steep streams, will be evaluated. The effects of groundwater on stream temperature patterns will be assessed by comparing the heat budgets of two sections of a stream that differ mainly in terms of the influence of groundwater discharge. Field work will also focus on stream temperature variability downstream of glaciers in relation to variations in weather and stream discharge.