Climate change impacts on stream flow and sediment yield in the North of Iran

Abstract

Climate change will accelerate the hydrologic cycle, altering rainfall, magnitude and timing of runoff. The purpose of this paper is to assess the impacts of climate change on stream flow and sediment yield from Gorganroud river basin in the North of Iran. To study the effects of climatic variations, the SWAT model was implemented to simulate the hydrologic regime and the SUFI-2 algorithm was used for parameter optimization. The climate change scenarios were constructed using outcomes of three general circulation models for three emission scenarios. The study results for 2040-2069 showed an increase in annual stream flow of 5.8%, 2.8% and 9.5% and an increase in sediment yield of 47.7%, 44.5% and 35.9% for the A1F1, A2 and B1 emission scenarios, respectively. This implies that the impact of climate change on sediment yield is greater than on stream flow. Monthly variations show that the increase in discharge and sediment yield is more pronounced in wet seasons and the decrease is more pronounced at summer (July-September). The results highlighted the strong impact of climate change and reflected the importance of incorporating such analysis into adaptive management