Perceptual modelling of environmental Indicators to assess land uses impacts on water quality

Streams’ functioning is closely influenced by land uses along the stream itself and throughout the catchment. Land uses could both translate the natural environment or results of increasing human activities. These different land uses generate various (positive or negative) pressures depending on kind and intensity that alter river water quality for different scales of time and space. The objective of this research, applied on the Saône River (France) is to conceptualize and quantify the interactions between river water quality and land use through spatial modelling. Our methodology is based on (i) the design of indicators’ system using the DPSIR framework (EEA) (ii) the development of relevant environmental indicators able to characterize spatio-temporal evolution of the water quality, land uses and their interactions. The conceptual framework DPSIR helps to understand the global nature and the complexity of the problem; however it constrains the selection and development of environmental indicators. Water quality state is characterized by a bioindicator based on the abundance and the sensitivity of benthic invertebrates that are able to integrate different kinds of pressures at different time scales. The identification of the pressure indicators has been done thanks a literature review. They were built according to the nature of the land use, distance to rivers and location in the watershed. The indicators’ construction has been limited by the representativeness and homogeneity of data gathered from national databases. These data were supplemented by a work of very high spatial resolution land use mapping and by the results of a spatio-temporal change detection analysis.