Modeling runoff management strategies under climate change scenarios using hydrological simulation in the Zarrineh River Basin, Iran

Abstract

Lake Urmia has experienced climate change over the last decades, dramatically reducing the water level. This study applies the Soil and Water Assessment Tool (SWAT) to evaluate runoff management strategies under different climate change scenarios in the Zarrineh River Basin. We examined two runoff management strategies: the projected runoff based on the business-as-usual (BAU) trend and the Changes in Cropping Pattern (CCP). The climate variables were downscaled and projected using Climate Change Toolkit (CCT) for the near future (2025–2049) and the far future (2075–2099) periods under two Representative Concentration Pathway (RCP) scenarios (2.6 and 8.5). The results revealed that runoff decreased by 6–23 and 9–52% for the near and far future, respectively, under the BAU scenario compared to the baseline period. Antithetically, it increased by 3.5–21 and 13–55% for the near and far future periods, respectively, based on the CCP strategy estimated up to 30% higher than the BAU strategy. The findings suggested that the CCP strategy can be considered a pragmatic management strategy since the surcharged runoff collected into Lake Urmia caused the mitigation of the imminent environmental disasters in the region and provided the environmental needs of its ecosystems. HIGHLIGHTS Two RCP scenarios of three GCM projected future climate in the ZRB.; Climate variables are expected to decline and rise in the ZRB.; SWAT presented good performances in simulating runoff in the ZRB, considering uncertainties.; Climate change results in decrease of future runoff of the ZRB under business-as-usual (BAU) strategy.; Implementing the changes in cropping pattern (CCP) strategy can help to increase annual runoff, which would increase the water inflow into Lake Urmia.;

Keywords

• climate change
• cmip5
• management strategies
• rcps
• runoff
• swat