Investigation of Environmental Changes around Hoze-Soltan Lake Using Meteorological Data and Remote Sensing techniques

Investigation of environmental changes is a necessity for maintenance and optimized utilization of natural resources. For this purpose, field measurements and region sampling, which are time-consuming and expensive, are implemented. In this study, precipitation, temperature and water level variations were investigated in the study area and evapotranspiration rates were calculated using Blanney-Criddle method. Moreover, remote sensing techniques such as Normalized Difference Vegetation Index (NDVI) and water index, MNDWI, were used to investigate the environmental changes. The study area is located around Hoze Soltan Salt Lake beside Tehran-Qom highway. The Landsat ETM satellite images of 2002 and OLI of 2013 in May were prepared to be used in this study. Using MNDWI, the Hoze-Soltan Lake area were estimated as 7835.857 and 6265.062 hectare in 2002 and 2013, respectively, indicating the reduction of lake area in 2013. NDVI index revealed that vegetation cover increased from 65.33 hectare in 2002 to 2942.61 hectare in 2013. Moreover; investigation of rainfall volume, temperature, evapotranspiration and water level using the available data revealed a declining trend of rainfall volume and water level and an increasing trend of temperature and evapotranspiration in the region. The results of this study indicated that some parts of the region around Hoze-Soltan lake were not inundated in 2013 because of the decreased water level. This has provided a good growth condition for more plants and for cultivation in some parts. The increase of vegetation covers and consequently the increase of evapotranspiration along with water level withdraw and precipitation declining trend emphasize the reduction of lake area during the study period as presented by the remote sensing techniques.