Data comprise a set of broadleaf afforestation scenarios (provided as netCDF files) that may be run with the Joint UK Land Environment Simulator (JULES), a community land surface model. The scenarios are based on the CEH Land Cover 2000 classification. Afforestation takes place according to catchment structure and existing land cover. Scenarios cover twelve river catchments in Great Britain: Dee, Tay, Ouse, Ure, Derwent, Thames, Avon, Tamar, Severn at Bewdley , Severn at Haw Bridge, Ribble and Clyde. Afforestation scenarios relate to two catchment properties: - (1) River network structure and (2) Land use. By using these two catchment properties, in conjunction with different extents of afforestation, up to 288 afforestation scenarios per catchment are generated. This dataset was created as part of the NERC doctoral training partnerships (grant number NE/L002612/1). Full details about this dataset can be found at https://doi.org/10.5285/f484ff54-9139-462e-b37a-347a69f78500