THE HYDROLOGICAL COMPONENT OF THE NELUP DECISION-SUPPORT SYSTEM - AN APPRAISAL

The NELUP decision-support system (DSS) has been developed to provide a quantitative description of the main economic and environmental impa cts arising out of rural land-use change at the river-basin scale. The system integrates models of economics, ecology and hydrology with rel ational and spatial databases, thereby permitting interactive evaluati on of different future scenarios through a graphical user-interface. T he models are coupled by means of data transfers via the database and allow, for example, the consequences of economic policies on agricultu ral production to be estimated in terms of predicted impact on water r esources and ecological diversity within a basin. The two hydrological modelling systems employed in the NELUP DSS, namely SHETRAN and NUARN O, are described. The utility of the hydrological component is illustr ated, making use of an application relating to the problem of stream-f ed irrigation in the Cam river basin.