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Flooding and Erosion

Floods most often occur during major storm events that produce large amounts of rain over short periods of time. There are three potential scenarios:

  1. Large amounts of rain over a short period of time where storm water drainage is insufficient. This is called a flash flood. Water rise may be sudden and with little warning. Additionally, after periods of drought, the soil can be too dry to sufficiently absorb the water in the short term (due to the lack of cohesion).
  2. Large volumes of water over an extended period of time. This type of flooding will occur over the duration of the storm, and the flooding may continue long after the storm passes. There will oftentimes be a lag between the event and the flooding as water moves through the hydrologic system. It may even be an event that did not generate heavy rain in your location, but areas upstream experienced significant rainfall.

  3. Storm-surge flooding from the wind and waves of hurricanes and tropical storms that result in the accumulation of excessive amounts of water along the coast. It is a combination of the low pressure of the storm allowing water to rise and the relentless surf pushing water inland faster than it can escape against the same waves back to deeper water.

While hurricanes are Florida’s most obvious flood producers, it is important to realize that heavy rains can cause flooding in Florida any time of the year and anywhere. Flooding may result in the loss of human life and property. Episodes of flooding may be accompanied by contamination of aquifers and water wells in some areas. Floridians should be aware of boil-water warnings posted in their local news media. It is vitally important that everyone living in Florida be aware of the potential for flooding and the resources available to assist Floridians in dealing with it.

Florida Department of Emergency Management

Federal Emergency Management Agency

National Flood Insurance Program

Coastal erosion has both natural causes and human-related activity causes. Gradual coastal erosion occurs naturally from fluctuations in sea-level and by longshore drift. Sand moves parallel to the coast in longshore currents. Ideally, the movement of sand functions like a balanced budget. Sand is continually removed and replaced at a location by longshore currents.

Structures such as piers, sea walls, jetties, and navigational inlets may interrupt the movement of sand and it can become trapped in one place by these types of structures. The longshore currents will continue to flow, though depleted of sand trapped elsewhere. With significant amounts of sand trapped in the system, the continuing motion of currents results in erosion. In this way, human development and construction activities resulting in the unnatural trapping of sand have the potential to result in significant coastal erosion over time.

The most severe coastal erosion can occur over a very short period of time when the state is impacted by hurricanes and other severe weather systems as a combination of storm surge flooding and wind and waves erode the coast.

Last Modified:
March 16, 2021 - 3:14pm

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