Numerical Modeling Of Thermal Stratification And Water Quality In Reservoir By CE-QUAL-W2 Model

One of the important issues in water quality management is the determination of thermal layering followed by nutritional levels in reservoirs of dams and other water structures. Determining the thermal layering using qualitative models. In choosing a water quality model, there should be an exchange between the complexity of the model, the reliability, the cost of operation and the time available. Determining the parameters of a nutritional index such as total phosphorus and total nitrogen concentration in the lake, the average and maximum chlorophyll a concentration, and the amount of dry algae using these equations requires minimum quality data and less time and cost compared to complex modeling The computer required .In this study, the water quality of the Mahabad dam in West Azarbaijan province, using the CE-QUAL-W2 model, efficient software in the field of reservoir analysis and examination of water reservoirs and lakes analyzed. According to the results, the Mahabad Dam reservoir has a relatively robust summer layering, which began last in April and reaches its peak in August, with the onset of autumn and at the same time as the amount of radiation entering the reservoir of layering has been formed. It also leads towards mixing so that in December, the complete mixing takes place in the reservoir. In terms of total concentration of total soluble solids (TDS), it can be said that the trend towards depth changes is rising, so that the maximum concentration is throughout the year at the bottom of the reservoir. The changes in dissolved oxygen relative to the depth of water in the reservoir are also reducing; these changes start from June and continue until last summer so that the concentration of dissolved oxygen in the substrate will drop to zero, which eventually produces a color And the unpleasant odor is in the reservoir. Mahabad storage dam is a dike dam on the Mahabad river, west of Mahabad city in the West Azerbaijan province. Mahabad Dam has a trifling capacity of 197 million cubic meters and 172 million cubic meters of useful capacity which in addition to supplying drinking water to Mahabad, causes under its coverage over 12 thousand hectares of agricultural land in the city. The dam also has a hydroelectric power plant. Construction began in 1968 and the dam was completed in 1970. In this research, a two-dimensional CE-QUAL-W2 model was used to simulate nutritional (eutrophic) in Mahabad dam. Then the geometry of Mahabad dam reservoir is introduced. To do this, using the topographic maps of the dam reservoir and the AutoCAD software, we produced cross-sectional profiles along the reservoir's line at specified intervals and obtained information by measuring the profiles at depths of two meters in depth. Come into the depth gauge . To investigate the sensitivity analysis, the following items were used: 1. Windscreen coefficient (WSC) 2. Light-to-water penetration coefficient (EXH2O) 3.Temperature Sedimentation Coefficient (TSED) 4. Solar absorption coefficient (BETA) 5. Viscosity coefficient of vortex Horizontal (AX); Horizontal Swing Diffuser (DX); Friction Coating Friction (FRICC).