Monitoring the spatio-temporal changes of watershed health using Vigor-Organization-Resilience (VOR) conceptual approach

Therefore, the purpose of the current research was to investigate the health of Koozeh Topraghi watershed using the Vigor, Organization and Resilience (VOR) model during the years 2000, 2010 and 2021. Ecosystem resilience is considered as the potential of an ecosystem to respond to external disturbances by restoring its original structure and function. Each type of land has a different ability to recover, depending on its nature.To calculate resilience, a coefficient was determined for all types of land uses according to the type of service for each user. The results showed that in Koozeh Topraghi watershed, the Vigor index has the mean and standard deviation of 0.88±0.05 in the first year, 0.81±0.08 in the second year, and 0.17±0 in the third year. Were 0.68. The Organization index had the mean and standard deviation of 0.57±0.08 in the first year, 0.70±0.08 in the second year, and 0.68±0.07 in the third year. Also, the resilience index had the mean and standard deviation of 0.28±0.22 in the first year, 0.30±0.25 in the second year, and 0.29±0.25 in the third year. Also, the watershed health index (WHI) in 2000 was equal to the numerical value of 0.49 and in 2010 it had an increasing trend and reached 0.85, but in 2021 it decreased to 0.47. It can be concluded that the health of the watershed has decreased slightly in the studied period. Various reasons, inappropriate land use especially pasture production for agriculture, and changes in climatic and hydrological components, have caused inappropriate health conditions in the Koozeh Topraghi watershed.