Evaluation of the Impacts of Climate Variability and Human Activity on Streamflow at the Basin Scale

Abstract

AbstractThis paper analyzes long-term trends and sudden changes in hydro-climatic variables (i.e., runoff) in Iran’s Aidoghmoush basin during 1971–2000 using the nonparametric Mann-Kendall test and curves of cumulative runoff versus rainfall and cumulative runoff versus temperature The use of the Mann-Kendall test with a 99% confidence level revealed a decreasing trend in annual rainfall and total runoff and an increasing trend in temperature. A sudden change in the gradient of the cumulative curves in 1988 indicated that the relation between climatic variables and runoff is influenced by human activities (agricultural water use). The interval 1971–2000 was separated into a baseline interval (1971–1988) and an impact interval (1989–2000), during which human activities affected runoff. The five-parameter hydrologic model of IHACRES (Identification of unit Hydrographs and Component flows from Rainfall, Evaporation, and Streamflow data) was calibrated and verified over the baseline interval to determine the ...