Fully-integrated hydrological modelling in steep, snow-dominated, geologically complex Alpine terrain

• Main Author: Thornton, James
• Format: Other/Unknown Material
• Language: unknown
• Published: Center for Open Science 2022
• Subjects: Ice; permafrost
• Online Access: http://dx.doi.org/10.31237/osf.io/zktsh

The rugged topographic forms and complex geologies that are characteristic of Alpine terrain typically exert a strong influence on catchment-scale hydrological processes. Glaciers, the seasonal snowpack, permafrost, and forests are other integral parts of Alpine environmental systems, and all are currently responding in one way or another to ongoing climatic change. Since a web of process interactions and feedback mechanisms link all system components together, any fairly direct hydrological changes arising from changing snow and ice could be modulated by the response of the broader integrated systems. Yet despite this complex reality, legacy conceptual or “box-type” hydrological models – which employ highly simplified representations of groundwater and other physical processes, and which moreover usually neglect contemporaneous changes in other system components – continue to underpin most predictions of future water availability in the European Alps. The reliability of some of the resultant predictions may there-fore be questionable. More sophisticated physically-based codes are available, but also employ simple subsurface representations. At the same time, numerous detailed field investigations have been carried out in alpine catchments, but are rarely extended to numerical modelling exercises. In this context, the present thesis sought to evaluate the utility of one of the most advanced fully-integrated surface-subsurface flow codes for simulating hydrological dynamics in steep, snow-dominated, and geologically complex Alpine headwaters – under both present and plausible future climate, forest, and permafrost conditions. Surface flows are particularly relevant in such terrain in terms of ecology, flood hazard, and sediment transport, whilst groundwater flow patterns can be strongly influenced by inherently complex three-dimensional (3D) subsurface structures. Furthermore, bi-directional exchanges between these domains can occur frequently, inducing streamflow ephemerality under certain circumstances. In having the ...