We seem to be overrun with silly people who think they need to build in the flood zone.?ÿ One was a very wealthy fellow who intended to build a grand home very close to his office building.?ÿ The office building was outfitted with several sliding glass doors such that flood water could run through the building when it needed to do so.?ÿ Wall outlets, table tops and any kind of paper files and electronics were on the order of three feet above the floor level.?ÿ Where he wanted to put the new house would result in the first floor having even more flood depth potential.?ÿ He had enough money that he could do whatever he chose to do and this was it.
He had enough money that he could do whatever he chose to do and this was it.
Some people have more money than brains...
Out in the rural part of the county FEMA did some new Zone AE flood maps along two of the more densely populated streams. An old client of mine stopped me at a grocery store and began a story of a house he bought as a rental that flooded this year. He wanted me to do a survey and get it out of the flood plain so he could buy flood insurance at a reasonable cost.
I brought up the site on my phone and sure enough even though it was a good distance from the stream the map showed a flood plain pushing out and over to the house, just like it did this year. I looked at him and explained there wasn't much I could do, you got conformation that it's in the flood plain this year and it's probably going to keep happening. He had heard that a survey could solve the issue. I told him it's hydrology, I can go out there and get an elevation, but it's going to no doubt be a foot above his finished floor which is where the water ended up this spring...??..
Then he tells me he's had the house for 8 years and this is the second time it's flooded.?ÿ Well, he could have started off with that little nugget.
In a Zone A, there is no established BFE . You have to either do a simplified Flood Study if the building site is touching the Zone A Boundary. If your building site is inside the Zone A boundary you have to do a Detailed Flood Study. The Detailed Flood Study requires cross sectionss above and below the building lot and a complete topo of the entire lot. If it's a small stream it's not too tough, but if it's a major river, getting the cross sections can be a challenge. It also helps to have a nearby stream gauge. I'd be looking for a hydrologist if it's a complex study. You can interpolate from previous Studies?ÿ if they were located fairly close by. Most Highway major bridges probably had a flood study done for their design. Check with the Highway Department. Depending on the site a Detailed Study can be easy and fairly cheap or very difficult and very expensive. If you're a one man shop with no experience, I'd be shopping for a firm with the equipment and experience in doing the Flood Study. You can do the lot topog and establish control. I only use NGS Benchmarks or OPUS elevations . Personally I think the OPUS derived elevations are more precise than the published NGS Benchmark elevations. NGS is begging Surveyors to observe their benchmarks with GPS, which leads me to believe they have some concerns with their published benchmark precisions. Either one is defensible, just depends on how anal you are in accepting data. ?ÿ A simple Elevation Certificate and a Detailed Flood Study are two different cats. If you do the study and your client's building floods with a less than a hundred year flood event you're to blame. If it floods when your Elevation Certificate says they are above the FEMA supplied BFE, FEMA is to blame. Remember BFE's are derived from statistics.
