Modeling of Non-Point Source Pollution by Long-Term Hydrologic Impact Assessment (L-THIA) (Case Study: Zayandehrood Watershed) in 2015

Background & Aims of the Study: In this research, Long-Term Hydrologic ImpactAssessment model is selected for simulation of runoff and NPS pollution. The aim of this studyis modeling of non-point source pollution by L-THIA model in Zayandehrood watershed in2015.Materials & Methods: In this study, analytical survey and investigation of references in thecontext of library studies has been used. Zayandehrood watershed is located in Esfahan, Iran.Required data in this study are land use, soil and precipitation data from studied period. The firstL-THIA model run and then the spatial distribution of non-point source pollution analysedwithin the study area. The annual average runoff volume, depth and the non-point sourcenitrogen and phosphorus load and the spatial distribution were estimated.Results: According to the study, we concluded that amount of nitrogen and phosphorus load inagricultural and residential areas are more serious and the nitrogen load due to nonpoint sourcepollution was larger than phosphorus load in Zayandehrood basin. The maximum runoff depth inthe region was calculated 501.371 cm and the maximum nonpoint source pollution obtained24244.27 kg. The results indicated the watershed likely is affected to impacts from urbanizationand agriculture.Conclusions: The results of this study can be used for urban planning and decision making in aneffort to protect water and habitat quality of Zayandehrood river. Integration of introduced modeland other hydrologic models can be increased accuracy and precision of results. Also, subwatershedscan prioritize for watershed management in in the vulnerable sections.

کلیدواژه ها:

HydrologyNitrogenPhosphoruswater qualityZayandehroodIran