There are a lot of myths about flooding in Houston and Harris County. With hurricane season once again on top of us, I thought this would be a good topic to discuss.
Myth #1: If I didn’t flood during any previous storms or hurricanes, chances are I won’t ever flood.
Most Harris County residents are vulnerable to flood because of Houston’s flat topography and impermeable soil. Not all storms deliver their rainfall in the same areas or at the same rate therefore just because you haven’t flooded yet, doesn’t mean it isn’t a possibility.
Myth #2: My house is not in a 100-year floodplain so I do not need flood insurance.
Flood maps are not always accurate since they are only update every few years. Even the FEMA maps can not be solely relied upon as risk indicators for flooding. These maps are good at indicating the possibility of flooding due to nearby water sources such as rivers and bayous, however, they do not take into account other sources such as ditches, storm sewers or recent construction in your area. In 2001, roughly 65% of the flooding caused by Tropical Storm Allison occurred in areas not mapped as a floodplain. A 100 year flood plain does not mean that a flood will occur once in 100 years, rather it means there is a 1 percent chance of flooding EACH year and a 26 percent chance of occurring during a 30 year period.
Myth #3: Land development causes flooding.
There have been strict regulations in place since the 1980’s that mandate controlled release of storm water anytime a new development is in the works. Although laying concrete over what was once soil can increase the amount of water runoff, strict provision make developers responsible for any additional flood hazards they create. Since no developer is going to put himself in the position of a class action lawsuit by homeowners, you can bet they do all that is necessary to provide proper runoff of excess waters.
Myth #4: A storm surge will stop our bayous’ natural ability to drain.
The majority of Harris County bayous and creeks are upland and drain by natural elevation and gravity. Most of these bodies of water flow into the Galveston Bay and a hurricane or storm surge will not prevent this process.
Myth #5: The Harris County Flood Control District is responsible for addressing all types of flooding.
The HCFCD is responsible for bayous and tributaries, whereas the city of Houston and other municipalities focus on underground storm sewers and roadside ditches.
