Assessment of the Analytic and Hydrologic Methods in Separation of Watershed Response to Climate and Land Use Changes

Climate change and human activities are two major drivers that alter hydrological cycle processes and cause changes in spatio-temporal distribution of water availability. Streamflow as the most important component of hydrologic cycle is expected to be influenced by climate change as well as human activities. Three methods including hydrological sensitivity procedure, slope change ratio of cumulative quantity and hydrological modeling by SWAT are investigated and compared for separating the impact of climate change and human activities on the Minab River flow in south of Iran. Also, nine scenarios are defined for development of agricultural land and urbanization to evaluate the effect of climate change and human activities within the SWAT model. Mann–Kendall and Pettitt tests are used to analyze the trends and the change point in the climatic data time series. Results show that the share of human activities and climate change are close in three methods. Scenario H9 that includes the development of agricultural land and urbanization by 30% compared to the present situation reduced the streamflow by 88.8% that is the highest reduction among the scenarios. Also, the results indicate that human activities are the main reason for streamflow reduction in the Minab River.