The aim of the project is to develop an ecological – hydro-dynamical model to show the changes in trophic status of the Szamos and Tisza rivers. The river network is a continuously changing complex spatial system, where the fate of pollutants and biota can be analysed by models. The developed model makes possible to identify permanent and conditional hotspots of pollutions, alga growth and decay, as well as to explain how these hotspots come to existence.The main activities of the project are: intense monitoring along the Szamos River, and up and down its mouth at the Tisza River, eco-hydrological modelling and scenario analysis and preparation of final report (the study should include (I) an executive summary with recommendations for management alternatives (Ii) background of the project, (iii) methodology, (iv) data analysis, including the analysis of the impact of the Szamos River on the ecological status of the Tisza River, (v) model calibration and modelling results; (vi) the results of scenario analysis; (vii) recommendations for management strategies).The target groups: - water and environmental protection agencies, research and planning institutions in the Szamos/Somes River catchment responsible for the implementation of the European Water Framework Directive.- population in the Szamos (Somes) catchment and in the Hungarian catchment of the Tisza River whose living is based on ecological services (drinking water, tourism, recreation, commercial fishing, angling, etc.) provided by these rivers.Among the project results: 1 database of water quality and ecological indicators along the Szamos (Somes) River, 1 study, 2 conferences.