Developing a system dynamics model for phosphorous TMDL in reservoir; a case study

摘要

Eutrophication is the phenomenon observed in the bodies of reservoirs that receive large influxes of nutrients especially phosphorous. Simulation models have been used as useful tools in the study of TMDL for eutrophication in lakes. In this study, a system dynamics (SD) approach is applied to simulate and analyze phosphorus concentration in the reservoir. It is done via an object-oriented modeling software namely STELLA. The modeling process consists of developing, stock-flow diagrams that consider both inflow and outflow of the reservoir for the phosphorous load. Two main processes in the reservoir phosphorous model are sedimentation and release between the sediment at the button and the reservoir water body. Model calibration and validation was done for a 41 month period data The model has been applied to determine TMDL in monthly scale for the allowable load input to the Satarkhan reservoir in Northwestern part of Iran. Results indicated the significant value of the model in the TMDL application.