Climate and landscape controls on the behaviour of catchment storage and streamflow

Abstract:

Streamflow is dictated by the volume of storage contained within a catchment and the hydrological processes that control how storage is released. The relationship between storage and streamflow can be complicated as it is known to be non-linear and sometimes hysteretic. As the key fingerprint of catchment emergent behaviour, there are benefits for understanding what controls this relationship and how it manifests in different geographic regions. Climate will control the typical amount of storage held within a catchment, and the predominant runoff generation processes that can occur. Spatially organized landscape traits such as topography, soils, vegetation and bedrock geology also, similarly, control the distribution of storage and predominant runoff generation mechanisms. This study utilized observed storage streamflow curves for two contrasting Canadian landscapes - the subarctic Canadian Shield and the semi-arid Prairie - to evaluate how catchment traits influence the characteristics of these curves. These characteristics include the degree of non-linearity, direction of hysteresis and location of breakpoints. Defining the characteristics of observed storage-discharge curves is important because they reflect catchment functioning. Furthermore, it will ensure the type and form of algorithms in catchment models reflects field based understanding. To this end, the form of observed storage-discharge curves were compared to theoretical curves from the literature to determine the most appropriate applications for these prediction of streamflow in these landscapes.