Extended Abstract
Introduction: The main goal of this study was to analyze and forecast the health condition of watersheds within third-order catchment basins across Iran, based on the variability of dynamic factors and their quantitative influence on future watershed health. The research takes a forward-looking approach, aiming to evaluate the state of watershed health for the years 2033, 2043, and 2053. The introduction highlights the importance of conserving and maintaining water and environmental resources for sustainable development, especially in a country facing diverse climates and significant human and environmental pressures. Watersheds play a vital role in water supply, flood control, and biodiversity conservation, making it crucial to understand the factors affecting their health.
Materials and Methods: In the study, key indicators and criteria influencing the health of priority watersheds in the country were collected and analyzed. These indicators were divided into two groups: static and dynamic. Initially, 173 indicators related to environmental, climatic, and human factors were selected as pressure indices, 331 indicators of similar factors were chosen as state indices, and 13 human and ecological factors were designated as response indices. After standardizing the averages of these indicators, the health status of watersheds for each targeted year was estimated by combining and weighting these indicators. To analyze the effects of independent variables on watershed health, multiple regression methods were used. These variables included maximum and minimum temperature parameters, land use, and vegetation cover levels.
Results and Discussion: The results showed that in 2033, watersheds in the northern regions —especially in Gilan and Mazandaran—are expected to remain in good to very good condition (about 60 to 70% of areas), owing to extensive forests and sufficient rainfall. Conversely, in the southern regions such as Hormozgan and Sistan and Baluchestan, conditions were assessed as weaker (around 40 to 50% in moderate to poor categories). By 2043, this trend continued in the north and northwest, mainly because of persistent dense vegetation cover and adequate rainfall. However, in eastern and southeastern areas, decreasing rainfall and human pressures resulted in an increase in unhealthy areas to roughly 50 to 60%. By 2053, regional differences became more prominent; in the north, especially in Gilan and Mazandaran, abundant rainfall and dense cultivation helped sustain relatively healthy conditions (about 40 to 50%). In contrast, in eastern and northeastern regions, reduced rainfall and increased human activities led to a decline in watershed health, with healthy areas falling to approximately 30 to 40%. Analysis indicates that temperature fluctuations, particularly changes in minimum temperatures, play a highly sensitive and significant role in altering watershed health. The impact of these fluctuations in each of the three years exceeds 47.66% on the health index. These findings emphasize the importance of managing climate change, land use modifications, and vegetation cover for the sustainability and health of watersheds in the country. The effects of dynamic variables related to land use and vegetation cover are steadily increasing, and by 2053, their influence on the health index is expected to surpass 33.5%.
Conclusion: This study highlights that future planning should focus on controlling and managing temperature fluctuations, human pressures, and land use changes, as these factors directly and significantly affect the health and sustainability of water resources and ecosystems. Management actions and policy decisions in climate management, including adherence to or modification of land use patterns and preservation of vegetation cover, can play a crucial role in improving and maintaining watershed health. These results highlight the need for ongoing monitoring, strategic planning, and the sustainable use of natural resources in the future.