Analysis of Changes in the Bakhtegan Lake Water Body under the Influence of Natural and Human Factors

Bakhtegan Lake, as other lakes and wetlands, depends entirely on the state of water resources of the basin. The lake has been dried up since few years ago. It is believed that periods of drought events have caused this. Meanwhile, there is another hypothesis that the lake has dried up due to anthropogenic activities such as the increased water exploitation in the upstream as well as the effects of two large dams named Mollasadra and Sivand. The present paper aims to assess separately the effect of these factors on the changes in Bakhtegan Lake in the period of 1956 to 2014. The assessment was carried out using the Landsat satellite images and also by analyzing rainfall and discharge data collected by the Ministry of Energy throughout the lake basin including Kor River. To determine the amount of changes in the lake water volume the maximum likelihood classification method, in order to classify images, and post-processing comparison method, for verification of classified landuse of Bakhtegan Lake and its surrounding area, were adopted. The results showed that the reduced rainfall, and more importantly, the increase in the irrigated cultivated area in the upstream of the basin, which has resulted in increased water consumption, can be identified as the main causes of the lake drying up. The second factor has caused the problem of drought-induced water shortage to be transformed into a water crisis.