Trans-boundary land cover changes and its influences on water crisis: Case study of the Aras River

摘要

In a watershed, disturbing land covers (LCs) are one of the most important factors in the balance and flow rate of water. This study aimed to monitor and model LC changes in the upstream of the Aras River Basin in Turkey over 1984, 2002, 2010 and 2016. The main ground to conduct such an analysis was to mitigate severe economic, social and ecological consequences driven by agricultural activities and dam construction along with probable climate change, which would decrease the water flow from the Aras River to Caspian Sea. The study approach consisted of four main steps: 1) producing LC maps using Landsat satellite images, 2) performing the change analysis, 3) identifying the change driver variables for each of the calibration period, and 4) identifying the most accurate scenario and predicting maps of the years 2026 and 2036 based on the calibration periods (i.e., 1984-2002 and 2002-2010) using the Land Change Modeler (LCM). Moreover, the net changes in each LC were studied as well the transition from one LC to another and the spatial pattern of these changes over a 32-year period. The results show the growth of agricultural, industrial and residential lands in the upstream during 1984-2016. This trend seems to be more critical in 2026 and 2036. The construction of small to medium sized dams and redirecting rivers in order to supply water for increasing agricultural lands and industrial/municipal areas will affect the quantity of water flowing to downstream. This decreasing trend in water flow of upstream areas will intensify the shortage of water used for agricultural, industrial and drinking purposes in downstream countries in future. This study suggests that the Aras River Basin, as one of the most important feeders of the Caspian Sea, needs more protection and monitoring programs. Likewise, similar studies must be conducted in Iran, Armenia and Azerbaijan given these countries plan to preserve the quality and quantity of the Aras River.