Eco-hydrological process simulations within an integrated surface water-groundwater model

There are several key modelling challenges in addressing the complementary requirements of the Water Framework Directive and the Groundwater Directive. The first is to consider groundwater, surface water, water quality and ecosystems as an integrated system and develop modelling tools capable of representing these interactions. For example, the restoration of wetlands often requires an understanding of the interaction of surface water and groundwater quantity and quality. Secondly while static indicator-based or statistical approaches are widely used for overall management, the actual ecosystem is highly dynamic and both the actual response to different threats and impact of measures will also be dynamic. To address these challenges a new integrated eco-hydrological modelling tool has been developed that allows hydrologists and ecologists to represent the complex and dynamic interactions occurring including surface water groundwater interactions within a catchment. This is achieved by integrating a general ecological modelling tool into an integrated catchment hydrological modelling framework, MIKE SHE. The capabilities of this new tool are evaluated using analytical solutions and laboratory experiments. Finally we demonstrate the practical application of this tool to two case studies where the interaction of surface water and ground water are important for the ecosystem. The importance of the surface water groundwater dynamics for a riparian wetland on the Odense stream in Denmark is examined and simulations compared to field observations in the wetland. The Silver Creek ecosystem is controlled large-scale interactions of surface water and groundwater systems in the Lower Wood River Valley, USA. We examine ecological impacts related to the flows and temperatures in the Silver Creek ecosystem which are important for the fish population. We show that different water management scenarios can have significant impacts on the ecosystem