The original BFIHOST model (Institute of Hydrology Report No. 126, 1995) was found to underestimate BFIHOST in small clay catchments, resulting in higher runoff volumes and peak flows than expected from ReFH2. A method for applying ReFH2 in these catchments was therefore developed; WHS, 2018. Applying ReFH2 FEH13 in clay dominated catchments.
The BFIHOST19 descriptor model was developed in 2019 (Griffin et. al., 2019). This aimed to address a number of issues, including those within small clay catchments, related to the original BFIHOST model.
In general, BFIHOST19 can be considered to supersede the use of BFIHOST or any related adjustments within clay catchments. However, as in all catchments throughout the UK, it can be useful to utilise local/alternative data to provide confidence in results. This can include sensitivity analyses utilising alternative sources of BFI values e.g. observed BFI values from (nearby) gauged data, as well as more detailed analyses of local soils/geology.