Climate change impacts on ecological conditions in streams

In many parts of the world, the water environment is strongly influenced by consumption of water for drinking and household purposes as well as for agricultural and industrial activities. In Denmark, over utilization of groundwater resources for drinking water purposes is particular critical in the larger capital region of Copenhagen and in Western Jylland where groundwater is used to irrigate sandy soils. In these areas, groundwater abstraction influences stream flow quantities to such a degree that the water environmental conditions become harmful to fish and other living organisms. The problems are partly related to the traditional independent management of surface and groundwater resources.
The present project focuses on the development of an integrated model tool combining regional calculations of the water cycle with selected bio-indicators of Danish streams. The method is based on a combination of hydrological and habitat-hydraulic modeling to analyze and quantify impacts of climate variations, land use and groundwater abstraction on ecological conditions in Danish streams. Optimal (reference) conditions will be identified for Danish streams and the sensitivity to discharge, temperature and oxygen is determined through the incorporation of preference values in the stream habitat model. The habitat model will be coupled to a hydrological model (MIKE SHE) which is providing information about the stream flow. Deviations between reference conditions and current water stream conditions indicate the ecological quality of the water stream.
The model tool facilitates consideration of climate change processes and uses ecological based criteria to help decision makers improve the management of stream flow and groundwater resources.