Recommended Practice: Use of Digital Elevation Data for Storm Surge Coastal Flood Modelling

Storm surges and tidal waves are global phenomena that considerably affect human populations in coastal and island regions. According to the Guide to Storm Surge Forecasting published by the World Meteorological Organization in 2011, storm surges can be defined as “oscillations of the water level in a coastal or inland body of water in the time range of a few minutes to a few days, resulting from forcing from atmospheric weather systems. According to this definition, the so-called wind waves, which have durations on the order of several seconds, are excluded”. Storm surges are a coastal phenomenon triggered by strong winds in the oceans and seas due to tropical cyclones and other similar weather systems at sea.

Tsunami modelling, sea-level rise studies and storm surge hazard mapping have been done using deterministic and probabilistic models. However, deterministic models require precise oceanographic data, as well as data on bathymetry in the coast, coastal geometry and high-resolution digital elevation models in the coastal area and ancillary data on surface roughness in coastal areas. In many developing countries these data sets are not available.