Abstract
This study describes the applicability of the Catchment hydrologic cycle Assessment Tool (CAT) for improving the water cycle in a river basin, and suggests appropriate water cycle improvement methods for adapting the impact of future climate change on river basin hydrology. For future assessment, the Gyeongan‐Cheon River Basin located in the north‐eastern part of South Korea was selected. To evaluate future water cycle improvement, the data from two general circulation models (GCMs), MIROC3.2 hires and HadCM3 with A1B and B1 scenarios, were adopted and downscaled by using the Long Ashton Research Station–Weather Generator (LARS‐WG) after bias correction with 30 year (baseline; 1970 ~ 2000) ground measurements. The future annual surface runoff, groundwater flow and evapotranspiration changed up to +49, −45 and +44% in the late twenty‐first‐century of MIROC3.2hires A1B scenario and up to +56, −44 and +47% in the late twenty‐first‐century of HadCM3 A1B scenario. Under the condition of water cycle improvement are included by facilities, the hydrological cycle was enhanced by increasing groundwater flow and evapotranspiration, and decreasing surface runoff. The future annual surface runoff, groundwater flow and evapotranspiration were improved by −38, +13 and +24% in the late twenty‐first century MIROC3.2hires A1B scenario, and by −38, +13 and +25% for the HadCM3 A1B scenario. Copyright © 2016 John Wiley & Sons, Ltd.