In my studies, I use fully-integrated groundwater-surface water modeling approach as a tool to study groundwater-surface water interactions processes within boreal groundwater dependent ecosystems (GDEs) i.e. the ecosystems which functions and structure depend on the presence of groundwater. The current EU and Finnish legislation require assessment of the impacts of various land uses and groundwater abstraction to GDEs. However, our current state-of-the-art knowledge and modelling methodology are still insufficient to explain and simulate thoroughly mechanisms of all hydrological processes occurring within the GDEs and thus, challenges meeting these protection requirements. Fully-coupled physically-based models solve groundwater and surface flow equations simultaneously and thus, they are excellent tools to study interactions between subsurface and overland flow domains and to provide us information how various GDEs will respond to changes in hydrological and climatic conditions.
Many groundwater dependent ecosystems e.g. Aapa mire emerge as a result of regional groundwater flow paths, whereas others, such as, springs, spring fens are more local features. Thus, the thorough picture of groundwater-surface water interactions in northern conditions can be only revealed by studying these systems across various scales ranging from local systems to sub-catchment or regional ones. Until now, modelling studies mostly focused on small-scale applications. However, from water resource management and ecosystem protection perspective perhaps more valuable I insight provide regional scale studies. The largest difficulty in regional scale modelling is that the scrutinized characterization of extensive areas through in situ measurements is with current measurement technique challenging, if not impossible, due to large spatial extent, remoteness and heterogeneity of such landscapes and thus, it emphasizes the importance of a proper model parametrization and calibration. This PhD project addresses the issue of identifiability of model parameters related to modelling of both, local and large-scale groundwater systems using sensitivity analysis and uncertainty estimation methods in order to enhance our hydrological understanding of groundwater-surface water interactions in GDEs. In order to decrease the main drawback of fully-integrated modelling approach i.e. long running times, I am utilizing high-performance scientific computing services.
The main objective of the PhD project is to answer the following research questions: