Wetlands are unique, diverse, and productive habitats in the natural environment. They have significant ecologic values due to their potential to deposit, sediment, and filter out pollutants from the water that flows through them. Wetlands have been investigated from different aspects in the past years; however, the computer modeling of the complex processes that occur in wetlands has attracted less attention. In this study, the mechanism of pollutant removal has been studied by developing a new template for the ecological modeling of the wetlands. The kinetics of oxygen balances, biochemical oxygen demand, coliform, and nutrient removal are numerically simulated. To explore modeling capabilities, a wetland in northern Iran, was investigated as a case study. Field measurements were performed for parameter estimations and model calibration. The numerical results exhibited that concentrations of BOD, total coliform, phosphate, and nitrate decreased up to 45%, 44.96%, 44.8%, and 43.47%, in the outflow when model has run for spring and summer seasons and the results compared to the field sampling data.

Considering the relative good potential of ground water in Gharesoo basin, compared to surface water, quantitative and qualitative studies of ground water resources in this area is very important. Followed by the basic studies such as effective pollutant resources, the qualitative studies were done on the selected places. The test points were consisted of deep and semi-deep wells. The distribution of these stations on the basis of uniform distribution has affected the Gharesoo sub-basins and pollutant resources. Thus 57 stations were chosen for sampling. Because of small variation of qualitative parameters of ground water, sampling in both wet (Ordibehesht month) and dry periods (Mehr month) and nessesary qualitative tests of samples were done. The tests consisted of anions, cations, colliforms, EC, TDS, BOD and COD. The results indicated increased rate of pollutants toward the north west or exit point of the Gharesoo basin and this was coordinated with decreasing the depth of ground water and its direction of movement. Furthermore, in more than 90 percent of places, quality of water was suitable for agriculture and drinking. The main reasons for the low quality of water for agriculture and drinking was high EC and TDS parameters in the proximity of Gharesoo exits. On the basis of Gibbs Diagram and ratio of Ca to Mg ions (less than one), dolomite minerals are dominant.