Simulation modeling of nutrients, dissolved oxygen and total dissolved solids in Peer-Bazar River and Anzali wetland eutrophication prediction.

The Peer-Bazar river delivers pollutants in the water bodies of Anzali International Wetland especially during flood events. Here, the two-dimensional (2D) finite volume hydrodynamic models for the prediction of nutrients are developed. The model is based on the mass balance equation including advection and diffusion transport and chemical and biological transformation considering the impact of inflowing river and climate change. The model is formulated to simulate nutrients such as Amonia-Nitrogen (NH₃-N), Nitrate (NO₃-N) or overall Total Nitrogen (TN), Phosphorus (PO₄^3-) or TP, Dissolved Oxygen (DO) and Total Dissolved Solids (TDS) and prediction of spatial and temporal distributions of concentration of each parameter in the Peer-bazar estuaries leading to the Anzali International Wetland. Ten points of the Peer-bazar River were studied during an 18-month period from June 2014 to December 2015. The simulation and numerical analysis of water quality parameters were conducted in a 2-dimensional approach using the geometric and topographic data and imposing boundary conditions. This research used the software developed by the author, FLOW-3D mathematical model, and HEC-RAS for simulation and qualitative evaluation of the river. Results revealed that the mean concentration of phosphorous, nitrogen and TDS exceeded the permissible limits reported by the European Directive 80/778/EEC and OECD and USEPA standards. Therefore, water of the region is subject to the advanced eutrophic conditions. Simulation predictions showed that the variation in TDS and nutrients contents will increase in the next coming years and the region will reach to the stable conditions. Using regression, a relationship between EC and TDS was obtained in the next step. Comparing the results obtained by the simulator and the values measured in laboratory indicated the suitable performance of reference values. [ABSTRACT FROM AUTHOR]