Flow and transport in lowland area aquifers are strongly influenced by recharge processes and interactions with the surface water network. In lowlands, the groundwater table is close to the topographic surface. Therefore, the interactions between groundwater, atmosphere, soil, vegetation and surface water take place over short distances, within the so-called critical zone. Because of these short distances and the non-linearity of flow processes in the critical zone, a correct representation of these processes in catchment/regional scale groundwater models remains a challenge. This thesis presents an attempt to improve the representation of critical zone water transfer processes in a temperate lowland area catchment scale groundwater model while maintaining computational costs reasonable. In particular, the representation of groundwater – surface water interactions and groundwater recharge were studied in depth. The general approach used in this work is a bottom-up upscaling. First, processes are mechanistically simulated at a smaller scale (point and field scales), considering the small scale spatio-temporal features of the system. These simulated processes are then averaged or aggregated to a larger scale (catchment scale) and functional relations between larger scale averaged processes and features of the smaller scale structure are derived. In this way, small scale process understanding is effectively used to constrain relations that emerge at larger scales.
|Qualification||Doctor of Science|
|Date of Award||12 Jan 2020|
|State||Published - 1 Dec 2020|