10. Is there any way to mitigate the consequences of storm surges?

  • Identify high risk areas prone to storm surges (storm surge maps).
  • Collect empirical data needed to obtain return period curves for flooding and storms (particularly for countries with emerging economies).
  • Operate a storm surge forecasting system.
  • Develope / improve an information and warning dissemination system.
  • Evacuate high risk areas (e.g. low lying coastal areas) when a storm surge / hurricane is forecasted.

Damage reduction is the core of hazard mitigation, defined as the cost-effective measures taken to reduce the potential for damage on a community from the hazard impact. Hazard mitigation is sustained action to reduce or eliminate the long-term risk to people and property from hazards and their effects. A hazard mitigation programme should have 5 main objectives:

  • Maintain and if possible enhance environmental quality;
  • Maintain and if possible enhance life quality;
  • Identify intergovernmental equity;
  • Identify community concerns and issues;
  • Foster local resilience to disasters.

Basically coastal risk mitigation can be grouped into four main areas:

  • Planning: relates to beach and coastal management plans. Coastal hazards should be identified and addressed at the planning stage in coastal development, so that high risk are identified and where possible, the public directed away from the high risk area, or warned.
  • Education: refers to coastal safety education starting from primary school; it also includes all beach users including national and international tourists
  • Safety resources: refer to the personnel and resources.
  • Medical support: the back up if someone is rescued or resuscitated and in need of urgent medical attention. This includes access for ambulance and helicopters, nearby medical support and well-trained and equipped lifeguards.

People should be moved out of low-lying areas when a storm surge / hurricane is forecasted. Therefore warnings similar to that espoused for tsunamis, are needed in all areas at risk. Empirical data needed to obtain return period curves for flooding and storms are not available for the bulk of Third World countries, so a storm induced surge is estimated by mathematical models e.g. the WES Implicit Flooding Model (Butler and Sheng, 1982). The US National Weather Service has the SLOSH model (Jelesnianski et al, 1992) for real time forecasting. Inputs need minimum central air pressure, storm radius, storm track and speed. Short period ‘wave run up’ is omitted and the model is regularly used in the US. Other models also exist, e.g. Hubbart and McInnes, (1997) which treats the land-water boundary as a moving interface, with inland grid cells flooding as the water level rises.

Butler, H.L and Sheng, Y.P. 1982. ADI procedures for solving the shallow water equations in transformed co-ordinates. Proc 1982 Army Numerical Analysis and Computers, ARO report, 82-3. 365-380.
Hubbart, G..S and K.L McInnes, 1997. A storm surge inundation model for coastal planning and impact studies, J. Coastal Research, 15, 168-185.
Jelesnianski, C.P., Chen., P., and W.A Shaffer, 1992. SLOSH: Sea, lake and overland surges from hurricanes. NOAA, National Weather Service, Silver Spring, NOAA Technical report, NMW 48.