Rainfall-runoff response and thresholds in a Boreal landscape

Abstract:

Although it is recognized that catchment characteristics, such as topography, soils and vegetation, influence rainfall-runoff responses, the detailed knowledge on the variability of the responses and their controls remains limited, especially in the boreal region. Runoff responses have been shown to be highly variable across space and time, and can be seen as a result of interaction between many complex hydrological processes. Analysis of spatiotemporal variability in streamflow responses and threshold behaviour can lead to improved understanding of landscape hydrology, underlying controls and emergent properties.

Here we investigate how rainfall-runoff responses and thresholds for runoff generation vary in space and time for 14 nested subcatchments in the 68 km² boreal Krycklan catchment. By comparing streamflow responses and threshold behaviour for catchments with both similar and contrasting characteristics, we identify controls on the spatiotemporal streamflow variability in the landscape under different hydro-climatic conditions. We hypothesise that catchment characteristics such as vegetation, soils, topography and scale have a marked influence on streamflow responses, and that their influence varies with season and antecedent water storage in the landscape.