Calculate Flood Return Period using Tide Gauge Data 

GeoTide calculates (from tide gauge data) the floodreturn period (in terms of years) as a function of seadefence height. 

The combined effect of the normal regular tide and weather induced residual can result in tidal flooding, depending upon the height of seadefences. Weather induced variations in the tide are caused by atmospheric pressure and wind and its effect upon the ocean. When these effects are large, such fluctuations are known as tidal surges. Surges can be surprisingly frequent. For example, around the East coast of the UK, tidal surges of one or even two meters occur several times per year in some locations. Being caused by weather, tidal surges are difficult to predict and unlike the normal tide cannot be tabulated in advance.
Surges can occur at any time, and so it is more likely they will happen during neap tides or spring low tides, in which case overtopping almost certainly will not occur. However, when surges happen at the same instant as a spring high tide, overtopping of sea defences is much more likely. The statistics of flooding is therefore the result of the combined effect of the statistics of the astronomical tide and the statistics of the residual tide, this is known as the joint probability method or JPM. Using this method, GeoTide provides statistical estimates of the floodreturn probability and floodfrequency for a given height of seadefence.


© 2020 Copyright Geomatix
