Multi-criteria evaluation of the environmental carrying capacity (ECC) of Gharesou watershed in Ardabil province to optimal utilization of watershed resource

To manage natural resources in a watershed area, it is essential to evaluate its environmental carrying capacity (ECC) and consider it for sustainable watershed management. This study evaluated the ECC of 27 sub-watersheds in the Gharesou watershed, Ardabil province, which has diverse land use practices and high population density. The study considered five whighted criteria, including physical condition, watershed management, socio-economic status, industrial investment and land value, and land use to calclulate ECC index for each sub-watershed. The Gharesou watershed has moderate ECC (0.4–0.6), while upstream and downstream areas are moderate to good. Meanwhile, the middle regions have a very low ECC due to poor vegetation cover, overuse of natural resources, inappropriate land use, erosion, and population density stress. Factors such as river flow regime, water yield, sediment production, flood frequency, and water consumption index play a significant role in ECC estimation. The classified ECC categories can be used as a guide for land restoration and water resource management. Land value is crucial in the middle regions, and lower sub-watersheds have unfavorable physical conditions. Land use is favorable only in sub-watershed 17. The study’s results can optimize watershed resource management and prioritize restoration measures to strengthen ECC. The methodology can be applied to other regions to evaluate their ECC and provide data for effective watershed management. Determining ECC changes over time can help predict its status in the future.