assessment of the interactions between natural climate variability and human activities on runoff

in this study, long-term trends and abrupt changes of hydro-climatic variables was investigated in the observed period 1971-2000 for aidoghmoush basin using mann-kendall nonparametric test and cumulative curve of climatic variables-runoff, respectively. results show decrease trends for rainfall and runoff and increase trend for temperature by the mann-kendall test with a confidence level of 99%. change of cumulative curve gradient of climatic variability-runoff indicates that the relationship between climatic variables-runoff could be affected by the human activities. with identification of curve gradient change point, observed period was divided to two sub-periods: base line period and period associated with human activities. to determine the effects of human activities on runoff, hydrological model was calibrated and verified in baseline period and by introducing hydro-climatic in period associated with human activities to model, runoff was produced. the results show that contribution of climatic variability and human activities in runoff decrease is 79 and 21%, respectively.