Water management scenarios evaluation by using simulation models, environmental impact indices and multi-criteria analysis

The safeguard of water resources requires an unitary and integrated action and needs a prevention not limited to single water bodies, but that takes into consideration all the phenomena and all the anthropic activities that, directly or indirectly, affect the quantity and the quality of water resources. Considering the growing demand and the competition for water resources, an integrated water resource management is expected to provide reasonable solutions. There is a need for taking into consideration non only the point sources of river water pollution (pollution loads discharged from urban and industrial wastewater treatment plants), but also the diffused sources (agricultural and urban). Integrated modeling is an essential tool used to manage water resources and it is indispensable for planning interventions that aim to achieve and maintain high water quality levels. If the number of possible management scenarios is high, it can be difficult to obtain a complete framework of the spatial and temporal evolution of the water body and the decision makers can be overburdened by quantity of information generated by simulation models, and find difficult to select the best scenario. In this paper a decision framework for river water management which includes quality aspects is presented. In particular, its first purpose is the application of the management model, “SWAT” (Soil and Water Assessment Tool, USDA-ARS, Arnold J. G. et al, 1999), integrated with the GIS ArcView to the study area. The QUAL2E model has been applied to evaluate the changes in the river water quality parameters. An objective entropy-based multi-criteria analysis, based on the method proposed by Srdjevic, B. et al., to assist decision makers in their assessment of various river basin management scenarios in terms of standard water quality parameters is proposed.