JBA's Comprehensive Flood Map (CFM) of Great Britain provides information on the flood hazards from river, coastal, surface water, groundwater, dam break and canal failure inundation. JBA has also produced a Comprehensive Flood Map for the Republic of Ireland and Northern Ireland, which covers river, surface water and coastal flood hazard. Of these flood hazards, JFlow was used in the production of the river, surface water, coastal (including wave overtopping), dam break and canal failure maps.

 

The CFM is mapped using a 5m Digital Terrain Model derived from LIDAR, radar and photogrammetry data. Inundation extents and flood depths are produced from the JFlow results for five different return periods, with the exception of the surface water maps (which have two rainstorm durations for each of three return periods).