Catchments are the fundamental landscape unit for understanding water quality and managing water resources. Contemporary environmental problems are being approached more than ever by stakeholders on the geographic basis of catchments, where the underlying physical, biological, and chemical science is complex. The EU Water Framework Directive required most European countries to restructure their national water administration along catchment boundaries. In this project, we explore the interactions between hydrological, biological and geochemical processes that shape terrestrial and aquatic ecosystems. An understanding of these interconnected ecosystem processes is required in order to understand responses of catchments and its water chemistry to climate change, atmospheric deposition, land-cover shifts and other drivers of environmental change.