Mehrdis Danapour, IGN, defends her thesis about groundwater by video link

Mehrdis Danapour defends her thesis by videolink

Coupled Groundwater-Surface Water Modeling for Sustainable Groundwater Management

Supervisors:
Professor Karsten Høgh Jensen, IGN
Professor Simon Stisen, GEUS

Assessment Committee:
Professor René Therrien, Laval University – Canada
Professor Roland Barthel, University of Gothenburg – Sweden
Professor Peter Engesgaard (chair), IGN

Summary:
Decline in groundwater level due to abstractions typically leads to decrease in groundwater inflow to streams and alteration of flow regimes. This can potentially have very adverse effects on aquatic ecosystems thus for a sustainable groundwater approach the link between groundwater and surface water is of the utmost importance. The objective of this Ph.D. thesis was to apply a coupled groundwater-surface water hydrologic model for sustainable groundwater management. Special focus was set on an adequate representation of subsurface heterogeneity, groundwater-surface water interaction, and temporal dynamics of hydrological responses at a catchment scale. The study area is located in the central part of Jutland in Denmark and extends over an area of approximately 4,900 km2. Due to high permeability of soil this area is mainly groundwater fed and the dominant land use type is agriculture with high irrigation demand. In order to enhance the physical representation of the system, especially with respect to groundwater flow a regional-scale flow model has been parametrized using Pilot points and geostatistical interpolation method. The model has been calibrated in a multi-objective function framework in which the water balance prediction uncertainty has been quantified with respect to the parameters and observational data worth. The highly parameterized model proved to be successful in terms of meeting different objective functions in addition to estimation of reliable parameters. The impact of groundwater abstraction on the stream flow alteration has been successfully simulated and evaluated. The application of empirically-derived ecological indicators combined with the hydrological model indicated a higher degree of vulnerability of aquatic ecosystems in the upstream of the catchment and smaller streams. A flexible, robust, and yet efficient groundwater optimization framework has been successfully developed. The developed optimization framework considers multiple constraints (stream flow criteria at multiple locations) for different management decision variables (e.g. groundwater abstraction for irrigation) at different management scales (from single well to group(s) of well clusters). The combinations of all these techniques have proven to have the potential to guide stakeholders and water resource managers in finding integrated solutions to groundwater-surface water management challenges.