Conus-wide model calibration and validation for CRESTv3.0 – An improved Coupled Routing and Excess STorage distributed hydrological model

•CREST was added a conceptual groundwater model and became CRESTv3.0.•CRESTv3.0 model was then calibrated for the entire CONUS region.•The calibrated CRESTv3.0 performs well in the eastern USA but not Mountain West regions.•The groundwater module help CREST model simulations in the eastern USA. The Coupled Routing and Excess Storage (CREST) is a flood-centric distributed hydrological model that has been widely used by researchers, educators, and decision-makers around the world since 2011. With growing public concern about the impact of climate change on water security, hydrological models such as CREST need to continue improving to provide more accurate simulations, more output products, and reduced application difficulties for users. In this study, an improved version of the CREST model (version 3.0) was proposed to consider the groundwater component of the hydrological cycle. A CONUS-wide CREST model calibration was conducted to provide usable model parameters for CREST users worldwide. The calibration improved the overall NSCE score from −0.97 to 0.11 over 3206 gauge points in CONUS. The validation results indicated that the CREST model performed well in the eastern CONUS but not in the Rocky Mountains and the Mountain West. The newly added groundwater module reduced the overestimation and the steepness of the falling limb during flood events in the eastern CONUS but drastically reduced the simulated water quantities in the mountainous regions.