Modeling Future Hydrological Characteristics Based on Land Use/Land Cover and Climate Changes Using the SWAT Model

The hydrological processes in watersheds can be modified by changes in climate and Land Use/Land Cover (LULC), leading to significant alterations in precipitation patterns, evaporation rates, and stream flow. Therefore, it is crucial to examine how these changes in climate and LULC will impact future hydrological responses, especially considering the growing water demand and agricultural activities. In this study, we first investigated the future climatic conditions of the Minab River Basin, Iran, by considering three CMIP6 scenarios (i.e., SSP1-2.6, SSP3-7.0, and SSP5-8.5 scenarios) from the CanESM5 model during 2021-2050 and 2051-2080. Next, the LULC maps of the watershed during 2035 and 2065 were projected, and the individual and combined impacts of LULC and climate on streamflow and evapotranspiration (ET) of the basin were evaluated using the SWAT model. The future precipitation and minimum and maximum temperature of the region were projected to increase up to 88%, 21%, and 12%, respectively, compared to the baseline period (1989-2014). According to our findings, it is projected that future alterations in climate and LULC will lead to a rise in evapotranspiration (ET), with potential increases of up to 12.8% solely due to climate changes and 2-6% attributable to LULC changes compared to the baseline period. Furthermore, the changes in LULC are expected to cause a decline in streamflow ranging from 2-11%. The impact of climate on streamflow, however, exhibited temporal variations and was influenced by the severity of future warming, resulting in diverse impacts across different climate scenarios. The seasonal and annual impacts resulting from LULC and climate and their implications for the region are discussed in this study.

Automated summary

The hydrological processes in watersheds can be greatly affected by changes in climate and Land Use/Land Cover (LULC), leading to significant alterations in precipitation patterns, evaporation rates, and stream flow. This study investigates the future climatic conditions and LULC changes in the Minab River Basin, Iran, and their impacts on streamflow and evapotranspiration. The results show that future changes in climate and LULC will lead to increased evapotranspiration, with potential increases attributable to climate changes and LULC changes. Additionally, changes in LULC are expected to cause a decline in streamflow, although the impact of climate on streamflow varies across different climate scenarios.