Analysis of the Effect of Climatic Factors and Drought on Inflow and Outflow from the Khuzestan Plain in the Karun Basin

In recent years, the outflows from the Karun Basin, especially in the interior of Khuzestan province, have decreased significantly. This study aimed to investigate the effect of climatic factors and drought on the inflow and outflow of the Karun basin in two parts (basin area inside Khuzestan plain and basin area outside Khuzestan plain).  The results indicate the onset of adverse climate change during the last two decades. During this period, especially in the last ten years, the study has witnessed a large decrease in rainfall compared to the previous decade in the Karun Basin. Changes in average, minimum, and maximum temperatures, evaporation and drought have also increased during the last two decades. Also, the results related to the effect of climatic parameters on the output discharge of the Karun basin showed that in Khuzestan province 83% of the output discharge changes were affected by climatic parameters (including rainfall, drought, and maximum temperature, respectively) and outside Khuzestan, 82% of discharge changes are due to climatic parameters (including rainfall, maximum temperature, and drought, respectively). Meanwhile, the surface currents of the basin during the last decade have been more critical than other decades and the output discharge outside Khuzestan (input to the province) has decreased by about 27%, and inside the province and the output of the basin has decreased by 44%, which due to the almost identical effect of climate on both areas, these changes can be attributed to the existence of other factors, including land management and human factors.