Habib Abbasi - Department of civil Engineering, Marand Faculty of Technical and Engineering, University of Tabriz, Tabriz, Iran
Mohammad taghi Aalami - Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran,
Mohammad Hossein Niksokhan - Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran
vLeila Malekan - Department of civil Engineering, Marand Faculty of Technical and Engineering, University of Tabriz, Tabriz, Iran

A new approach was presented to manage simultaneously reservoir outflow quantity and quality. Two strategies were used to control reservoir outflow quality: (۱) reservoir inflow control with Best Management Practices (BMPs) in the watershed and (۲) outflow management by reservoir operational strategy. Soil and Water Assessment Tool (SWAT) model was linked to a reservoir water quality simulation model (CE-QUAL-W۲), the linked watershed-reservoir model was coupled with Multi-Objective Particle Swarm Optimization algorithm (MOPSO) to find the best set of decisions to optimize the reservoir outflow quality and quantity objectives. The approach was applied to Alavian reservoir and its watershed, in Iran, for a ۶-year time horizon. The results show the proposed approach could reduce reservoir outflow phosphorus concentration while increasing downstream water supply. The implemented BMPs outperformed the reservoir operational strategy in terms of reservoir outflow quality reducing outflow phosphorus concentration up to ۴۵% comparing with current conditions. Among the four applied BMPs, filter strips had more effect on reducing nutrient loads.  

Best Management Practices (BMPs), Coupled simulation-optimization model, Reservoir Operational Strategy, Selective Withdrawal, Watershed-Reservoir System