Gil, Actually, many relatively small to large cities have 2 foot contour interval maps of their area to assist with planning, zoning, storm water management, etc. On a local level, some cities do use them to map the floodplain to within the two foot contour interval and some folks have told me you can use the elevation level from the maps to calculate the 100 year flood elevation for your property. I know of some folks that have used this data to build within a foot of the 100 year flood. The flood elevations are based on a number of calculations using the relationship between stream gauge data and elevation, historical rain gauge data, etc.
I do agree there is a fair amount of fudge in the numbers and the characteristics of a basin can and do change because of a number of factors including urbanization, etc, so building very close to the flood elevation is risky. There are folks that will and have built to within a foot of the 100 year flood plain. This reminds me of a house wiped out in the October 1998 flood along the Guadalupe River. They rebuilt it on steel beams so the floor of the house would be above the 100 year flood level. They had just finished their house a few months before the July 2002 floods and the house got washed away - again. In fairness, both floods were considered greater than 100 year events. Geary --------------------------------------------------------------------- Visit our website: http://texascavers.com To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
