چكيده به لاتين
In this research, the developed hydrological, sediment, and nutrient modeling, SWAT model, has been calibrated and validated in the Seymare watershed in spatial and temporal scale. The performance of SWAT model in simulation of flow, sediment, and nutrient cycles at different hydrometric and water quality stations have been evaluated using R2 (correlation coefficient) and NS (Nash-Sutcliff) indices. The important and effective parameters in simulating of hydrological, sediment, and nutrient cycles (nitrogen and phosphorus) in the SWAT model have been identified based on valid scientific references. Then, in the SWAT-CUP environment, the role of each parameter and coefficients have been determined and set accurately. The point source pollutions (urban and rural sewage, fish farming units, etc.), and non-point source pollutions due to agricultural and livestock activities (the type and amount of applied fertilizer and pesticides in the farms and the number of regional animals) have been introduced to the SWAT model as pollutant loads. In order to determine the role of each phosphorus pollutant source, various waste load allocation (WLA) scenarios have been evaluated in SWAT model. The results indicate complete phosphorus removals of five important point pollution sources (municipal wastewater of Malayer, Kermanshah, Dinavar, and Sahneh cities, Islamabad-Gharb and Sahne-Kangavar Aquacultures) have resulted in reduction of the mean phosphorus concentration from of 1.34 mg/L to 1.21 mg/L in the river basin outlet. The analysis on water quality simulation model results show Kermanshah wastewater treatment plant (WWTP) has significant effects on water quality degradation in the study area in comparison with other point source pollution units. Furthermore, the results indicate non-point source pollutions (agricultural and animal husbandry) and soil erosions have significant effects on water quality deteriorations in comparisons with point source pollutions. In this regard, applying only WLA programs have less effects on water quality enhancement in the river basin scale. To resolve the conflicts among various decision makers, GMCR-II (Graph Model Conflict Resolution-II) model is used to determine suitable WLA strategy. Iran Department of Environment (IR DoE), Kermanshah water & wastewater company, and Islamabad-Gharb Aquaculture as decision makers have defined strategies such as 1- Application of WLA and LA (load allocation) programs in river basin, 2- Application of no WLA and LA programs in river basin, 3- Application of WLA program of Kermanshah WWTP and LA programs of agricultural and animal husbandry activities, 4- Application of WLA program of Islamabad-Gharb Aquaculture unit and LA programs of agricultural and animal husbandry activities. The defined strategies have been considered in conflict resolution model, GMCR-II. The analysis show, implementation of strategy 1 with strategy 3 or 4 could results in the strong stable equilibrium.
