We recently received a question from a local 6th Grader regarding flood preparation…
My name is Molly and I am I sixth grader at a local middle school. I am participating in a program were we are researching a problem related to the Colorado 2013 flood. I have decided to research all about the infrastructure and architecture damage. I visited your website and I saw that you have great advice to help prepare your house for a flood. I was wondering if you could help me understand more about the damage to the houses and how to better prepare your house for a flood. -Molly
I am happy to help answer your questions regarding floods and flood preparation.
First, it is important to know that the Federal Emergency Management Agency (FEMA) maps all floodplains in all waterways throughout the country. These maps indicate the path that that a flood would take through a drainage area like a creek. They measure the probability of a major flooding event in terms of years. So for example, a 100 year flood is a flood that has a 1 in 100 chance of happening in any year (this of course means that you could have a 100 year flood two years in a row, or even in the same year, though it would be highly unlikely).
In general, buildings are not allowed to be built within a 100-year floodplain, however, there can be exceptions. In this case, the building itself must be designed to structurally withstand the forces created by such a flood. And if you’ve ever been in the ocean experiencing crashing waves, then you have a very slight idea of just how powerful these forces can be. Other techniques include architectural solutions that reduce the area of the building that would be exposed to floodwaters. An example of this would be to put the building up on stilts so the water in a 100 year flood would stay below the floor elevation of the building. You see this a lot in coastal regions.
Older buildings, and in particular, homes, that are built within a 100 year floodplain are often not designed to withstand such forces. And the result is that these buildings are typically damaged beyond repair in a 100 year flood event. There is really no way to prepare for such a flood as in most cases, it would require reinforcing the existing building to such a degree that it would cost as much or more than building a new building. So these owners would purchase flood insurance and hope that they never see a 100 year flood event in their lifetime. If they do, and if they are insured, then at least they would receive money to repair or replace their home after the event (and hopefully, they build on higher ground!).
I hope that helps!