CAESAR-GW a modified version of CAESAR-LF with improved groundwater model : an application to the Hull digital twin FLOODTWIN

BGS has previously modified the CAESAR-LF landscape evolution platform to include an improved approach to water partitioning and a simple representation of groundwater (Barkwith and Coulthard, 2015). This new platform, CLiDE, performed well in homogeneous geological settings, but was ineffective under more complex geology. CLiDE is also computationally expensive to run and difficult to keep updated due to fundamental changes in the CAESAR code that the platform is based on. This report describes improvements to the water partitioning and groundwater modules CLiDE platform and realignment with CAESAR-LF code, as implemented in the Hull and East Riding digital twin demonstrator FLOODTWIN (NERC NE/Z503411/1). To reflect the realignment with CAESAR, the new platform is called CAESAR-GW. This report covers the development of CAESAR-GW, testing of the model and calibration of the groundwater components to reproduce the observed groundwater time series recorded at nine observation boreholes in the study area.