Evaluation and Monitoring Water Quality Parameters of Reservoir Dam by Remote Sensing Method (Case Study: Golabar Dam)

Water, as one of the most valuable natural heritage, requires constant monitoring, because the health of all living beings depends on the quality of water. Since the electromagnetic spectrum returned from the surface of the water indicates its nature, satellite imagery can be used to assess water quality and map the distribution of different parameters of water quality which are useful for decision makings by environmental and water resource managers. The general purpose of this study is to extract a practical algorithm for obtaining Golabar dam water quality parameters using Landsat 8 satellite data. The water quality parameters selected are electrical conductivity (EC) and pH, which are the main parameters for determination of water quality. Regression analysis was performed between the measured values of the parameters at the three sampling stations and the reflectance values of the water surface obtained from the OLI Landsat 8 spectral bands. Regression models were used to obtain the values of both parameters in the dam area. Finally, by applying a regression model on the satellite image of the area, the zonation map of the parameters in the Golabar Dam was obtained for 12 months. Also, using the time series, prediction of the quality parameters of the last two months of the year was performed based on the parameters of the past ten months and the results were compared to the previously produced maps, which were the results of the regression analysis. It was observed that similar results were achieved in most zones. The zonation maps of both parameters showed that the water in the middle section of the dam has better quality than the margin areas and the values of parameters in hot summer months in some parts are out of range.