A simple water quality model as a tool for the evaluation of alternative river basin management plans

A key component in the implementation of Water Framework Directive is the development of a river basin management plan for each river basin district. Water quality models are important tools to test the effectiveness of alternative management plans on the water quality of the respective water bodies. The main objective of the present study was to develop and demonstrate the use of a rather simple water quality model as a tool for the evaluation of alternative water management scenarios for the river basin district of Evrotas. Furthermore an extension of the water quality model based on Monte Carlo simulation to provide for uncertainty identification is also exhibited. The model is based on the basic principles of the Streeter-Phelps model. A hierarchical approach was developed in order to delineate a complex hydrographic network into a series of water bodies being connected by convective terms. The pollution loads which were used as input data were related both to point sources and non-point sources. Based on the results a substantial removal of organic carbon load originating from the industrial activities is needed in order to achieve high dissolved oxygen concentrations throughout the entire hydrosystem even at the dry period.