Interpreting The Flood Insurance Study For Your House

If you are thinking about flood insurance, interpreting the flood insurance study for your home is important to making your decision.

Additionally, some areas are declared federal flood area, and are required by law to carry flood insurance. Those areas will have a flood insurance study.

100 Year Flood
You will see a section of the study that tells you about the 100 year flood chances. This is the flood that has a 1 percent chance of being equaled or exceeded in any particular year.  This 100 year flood statistic is the one used most often by federal and state agencies.

It is used by the National Flood Insurance Program as the base of managing flood plains and deciding whether or not an area needs flood insurance.

If there is a structure that is located in a area on map that is within the special flood hazard area shown, then it has a 26 percent change of having flood damage sometime during a 30 year mortgage period.

Base Flood
A base flood is the same as the 100 year flood.  Because it is the standard, or base, by which most federal and state agencies develop their programs for floodplain management and determine flood insurance requirements, it is called either a base flood or a 100 year flood.

Base Flood Elevation
The number known as the base flood elevation is a number listed in feet. This number is the height or depth of the base flood. This number is generally listed in relation to the North American Vertical Datum of 1988.

If the NAVD is not used, then the Flood Insurance Study report will specify which datum is used to determine the depth of the base flood, in feet, above the ground surface of a particular area.

Cross Section
Cross sections are used on the Flood Boundary Map, Flood Insurance Rate Map, and the Flood Profiles in a Flood Insurance Study (FIS). Drawing a hypothetical line based on the topographical information across a flood plain creates the cross sections. They are then used to compute a flood flow at any potential flood elevation.

You can look at the elevation of your home in relation to these cross sections and see the potential for flooding and flow.

Cubic Feet Per Second
The term cubic feet per second is a unit used to describe the rate of surface water that is flowing through open channels.

One cubic foot per second, or cfs, is equal to approximately seven and a half gallons per second of water flow.

Looking at the cfs for a given area can help you decide if your home or the home you are considering is in a great deal of danger in a flood zone or in a very limited amount of danger.

One to five cfs may not be an amount to worry about it the home or structure is on a rise. However, even one cfs can be devastating if the home is in a dip or valley.

Interpreting a flood insurance study requires understanding terms and topography, and can be tricky. Ask for help if you need it to determine what, if any, flood insurance is required for your home.

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