Hazard modelling firm JBA Risk Management has released its new set of U.S. flood maps. The maps, provided at consistent 30m coverage across the whole country, are designed for use in underwriting, pricing and risk management. The underlying terrain data, NEXTMap USA, is the most modern, accurate and consistent available. They are based on 2D hydraulic modelling of surface water (pluvial) and river flood (fluvial) for all rivers in the U.S. River and surface water flooding are provided as separate layers, enabling underwriters to make more informed decisions in cases where the insurance coverage differs according to flood source. Water depths are returned for each return period and flood type in all areas, and maps showing areas protected by flood defences and the standard of protection each defence offers are also provided.
The maps are accompanied by a flood event set, which is suitable as a basis for catastrophe model development and provides a detailed overview of the possible variety and scale of events that can impact the US. The event set incorporates explicit modelling of hurricane-induced and non-hurricane events and includes hundreds of thousands of synthetically generated flood events.
Left: St Louis surface water, right: St Louis river and surface water
Key features of the flood data include:
- Compatible flood hazard maps and event set;
- All U.S. rivers are mapped, regardless of size;
- Surface water and river flood provided combined or in separate layers;
- 2D, GPU accelerated, hydraulic modelling returning water depth for all return periods and both perils in all areas;
- Up to date U.S.-specific hydrological data;
- Provision of flood defence data, including defended area and standard of protection information;
- Separate event modelling of hurricane and non-hurricane induced flood events;
- Data will be upgraded annually.