Storm surge prediction for Clear Lake City

A recent article in the Houston Chronicle by Susan Carroll and Mike Ward dated January 5, 2018 presents the case for a new seawall on Galveston Island and Bolivar Peninsula.

The premise is that a direct hit by a major hurricane to Galveston and Galveston Bay could destroy many billion dollars worth of homes and businesses.  The potential impact will increase in the future by sea level rise resulting from climate change.

A proposed 17-foot barrier 60 miles in length could reduce the potential destruction by as much as 80% according to Texas A&M researchers.  This barrier is modeled after a system built in the Netherlands.

The flooding mechanisms the barrier would be designed to reduce are:

  • water pushed ahead of strong winds 
  • water rising due to reduced atmospheric pressure 
Both of these effects combine to produce storm surge.  Storm surge is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low pressure weather systems such as hurricanes.  It is a measure of the rise of water beyond what would be expected by the normal movement related to tides.  Most casualties during hurricanes occur as the result of storm surges.

The two main meteorological factors contributing to a storm surge are a long fetch of winds spiraling inward in the storm, and a low-pressure-induced dome of water drawn up under and trailing the storm
center.

The National Hurricane Center (NHC) maintains a set of models for inundation due to storm surge for the Gulf and East coasts of the US plus Puerto Rico.  The models are produced by simulating the effects of up to 100,000 hypothetical storms varying forward speed, radius to maximum wind, intensity (Categories 1-5), landfall location, tide level, and storm direction.  Please refer to the link below for details.

The model for coastal Texas shows significant flooding of the Clear Lake City area at high tide during a Category 5 storm.  This is the "worst-case" scenario for flooding due to storm surge only and it does not account for erosion, subsidence, sea-level change, or future construction.


The areas actually flooded would also be dependent on other factors such as rainfall amounts and intensity, and the rate of clearing of storm drains. The extremely high tide caused by storm surge would act to slow the drainage from inland waterways.

Residents of vulnerable areas such as Clear Lake City - are you aware of the storm surge risk?  Are you in favor of construction of a coastal dike to reduce that risk?

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