Builders Said Their Homes Were Out of a Flood Zone. Then Harvey Came.

[Rasulis]

Interesting article on a facet of development that most people are rarely aware of.

Builders Said Their Homes Were Out of a Flood Zone. Then Harvey Came.

An excerpt to summarize the long article.

What they did not know was that their home, and those of many of their flooded-out neighbors in this new section of The Woodlands, had been built on land that not long ago lay squarely, and sometimes soggily, in a flood plain.

A New York Times examination found that in the years leading up to Hurricane Harvey, with a surging local economy fueling demand for new upscale housing, the developers of The Woodlands had used a wrinkle in the federal flood-mapping system — along with many dump trucks’ worth of dirt — to lift dozens of lots out of the area officially deemed prone to flooding. What they had done, in effect, was create gerrymandered maps of risk.

A comment from a real estate agent in the area for 35 years and owns a home in the development.

“I personally believe, in hindsight, this should not have been developed.”

Our firm used to do large residential developments. When the real estate market crashed in the early 1990s, we switched to Public Work, and I was never happier. Dealing with a lot of those developers (not all) used to leave a bad taste in my mouth.

[cuafpr]

without reading the details depends on which flood zone they claimed, my house in ND was in a 100 or 1,000 year flood zone, but not the other ones... that summer after i moved away it flooded. I still remember watching people build homes on the inside of a Levee in Louisiana then getting upset when they flooded.. like REALLY.

[Milchshake]

Interesting article on a facet of development that most people are rarely aware of.

Builders Said Their Homes Were Out of a Flood Zone. Then Harvey Came.

An excerpt to summarize the long article.



A comment from a real estate agent in the area for 35 years and owns a home in the development.



Our firm used to do large residential developments. When the real estate market crashed in the early 1990s, we switched to Public Work, and I was never happier. Dealing with a lot of those developers (not all) used to leave a bad taste in my mouth.

I second that, doing DD with large developers like LendLease and Essex sucked hella balls. War of Attrition only begins to describe the experience.

[Kujako]

"flood zones" are an insurance term, not a scientific one.

[Gorgodeus]

"flood zones" are an insurance term, not a scientific one.

Not true. The gov't decides whether an area is in a flood zone or not. This is done scientifically, and insurance companies have zero impact in the gov'ts decision.

[Crissi]

"flood zones" are an insurance term, not a scientific one.

Flood zones are generally done using mapping software like GIS, using past historical flood data, and general geography. HAZUS is a product form FEMA that does this, as well as estimate the damage of various kinds of floods on an area. So...it is done fairly scientifically.

[Independent voter]

Sounds like someone is hoping to sue.

[Nathreim]

You can't predict something like Harvey it was a once in a millennia storm.

[Endus]

Flood zones are generally done using mapping software like GIS, using past historical flood data, and general geography. HAZUS is a product form FEMA that does this, as well as estimate the damage of various kinds of floods on an area. So...it is done fairly scientifically.

I think the point is more that flood zones are based on risk ratios; if you're in a "flood zone" then you can expect fairly regular flooding, depending on precisely the degree of risk they defined for it (which can vary between jurisdictions, or there may be gradations of risk within a given region).

It doesn't mean that if you're outside of the "flood zone", that you can't be flooded and the government fucked up if you get flooded. It just means the risk was deemed acceptably low, and you got unlucky, which happens.

Of course, the other issue is that a lot of these estimations are based, as you noted, on historical data, and we're currently shifting away from those historical norms, so that stuff's changing.

[Rasulis]

I think the point is more that flood zones are based on risk ratios; if you're in a "flood zone" then you can expect fairly regular flooding, depending on precisely the degree of risk they defined for it (which can vary between jurisdictions, or there may be gradations of risk within a given region).

It doesn't mean that if you're outside of the "flood zone", that you can't be flooded and the government fucked up if you get flooded. It just means the risk was deemed acceptably low, and you got unlucky, which happens.

Of course, the other issue is that a lot of these estimations are based, as you noted, on historical data, and we're currently shifting away from those historical norms, so that stuff's changing.

The accuracy of the flood maps itself is highly questionable. A lot of the old data is not pertinent anymore, and need to be discarded. The issue in this case is that the developer was allowed to amend the flood map by rising the ground elevations. In some cases by as little as 2 inches above the Base Flood Elevation level. Which hydrologists in their right might would think that this is a good idea? And put their signature and stamp on the plans?

There is a tremendous pressure on engineers to accommodate the developers’ needs. I’ll be the first to admit that we had done so in the past, and I am not proud of it. However, there is a line that we would not cross when it comes to sound engineering judgement affecting human lives. In this case, I think the developer, the engineers and FEMA crossed that line a long time ago.

[Endus]

The accuracy of the flood maps itself is highly questionable. A lot of the old data is not pertinent anymore, and need to be discarded. The issue in this case is that the developer was allowed to amend the flood map by rising the ground elevations. In some cases by as little as 2 inches above the Base Flood Elevation level. Which hydrologists in their right might would think that this is a good idea? And put their signature and stamp on the plans?

If it's the developer doing this, then they were stating they would be actually increasing the elevation to those levels.

If they didn't, that's an issue that likely has some legal recourse, because it's a developer who didn't build according to the plans they filed with the city. That's an issue of private lawsuits against the developer, though, not really the city.

[Crissi]

I think the point is more that flood zones are based on risk ratios; if you're in a "flood zone" then you can expect fairly regular flooding, depending on precisely the degree of risk they defined for it (which can vary between jurisdictions, or there may be gradations of risk within a given region).

It doesn't mean that if you're outside of the "flood zone", that you can't be flooded and the government fucked up if you get flooded. It just means the risk was deemed acceptably low, and you got unlucky, which happens.

Of course, the other issue is that a lot of these estimations are based, as you noted, on historical data, and we're currently shifting away from those historical norms, so that stuff's changing.

Well in terms of historical data, when using HAZUS i can see using the more intense floods more often, to reflect the heavier floods that are occurring. Just may need to retool what we define as 100 year, 500 year, 1000 year etc.

and I know in Houston, the planning was all willy nilly with little respect for the actual geography of the place, so better plan management is top of the list of fixes.

[Endus]

Well in terms of historical data, when using HAZUS i can see using the more intense floods more often, to reflect the heavier floods that are occurring. Just may need to retool what we define as 100 year, 500 year, 1000 year etc.

Yeah, I actually really dislike the "100/500 year" labels for floods and storms precisely because they're based on a presumption of a stable climate, which hasn't been true for the last half-century; those norms are changing, and we're already getting multiple 100-year storms per decade in some regions.

If you understand that they refer to that historical trend, it's fine, but it's a label that can be really easily misinterpreted.

[Rasulis]

If it's the developer doing this, then they were stating they would be actually increasing the elevation to those levels.

If they didn't, that's an issue that likely has some legal recourse, because it's a developer who didn't build according to the plans they filed with the city. That's an issue of private lawsuits against the developer, though, not really the city.

The minimum Base Flood Level Elevation is set by FEMA. County and City have the options to pick a higher elevation (can’t be lower), but in my experience, Texas’ counties and cities tend to just stick with FEMA’s numbers.

Developers can apply for exemption if they can prove that they have taken measures to mitigate the flooding. The keyword is proof. Most of the people I have met at Houston Building Departments would not know which end of a theodolite to look into. Let alone figure out a hydrology report.

[Crissi]

The minimum Base Flood Level Elevation is set by FEMA. County and City have the options to pick a higher elevation (can’t be lower), but in my experience, Texas’ counties and cities tend to just stick with FEMA’s numbers.

Developers can apply for exemption if they can prove that they have taken measures to mitigate the flooding. The keyword is proof. Most of the people I have met at Houston Building Departments would not know which end of a theodolite to look into. Let alone figure out a hydrology report.

So you think the city / county just took the dev's word for it?

because that honestly would not surprise me -_-

[Rasulis]

So you think the city / county just took the dev's word for it?

because that honestly would not surprise me -_-

Very likely. I have coauthored several geotechnical/environmental/hydrology reports for my daughter’s developments in TX (including one in Houston). I basically wrote the reports but somebody else signed it because I don’t have a Texas license. The person that signed those reports for me only has a PE license. No GE or Hydrology. I have never gotten any comments back.

Rather unusual in my experience. For a simple geotechnical/hydrology report submitted in San Diego or Los Angeles, I generally get something like half to one page of comments. On large complicated projects I can get up to two to three pages. Personally, I am not sure that they even bother to read those reports.

[Nellise]

Just so people don't blame Houston's government for this (I've seen Houston referenced a few times), the Woodlands is its own town about 30 miles north of downtown Houston. It's actually owned by companies, it's kind of weird. And really the reason it's getting any noise is its a town for rich people and bad stuff isn't supposed to happen to them.

[Rasulis]

Just so people don't blame Houston's government for this (I've seen Houston referenced a few times), the Woodlands is its own town about 30 miles north of downtown Houston. It's actually owned by companies, it's kind of weird. And really the reason it's getting any noise is its a town for rich people and bad stuff isn't supposed to happen to them.

I think you are right. They are under the jurisdiction of Harris County.

[SirBeef]

The whole Huston metro area is a flood zone only made worse and larger by piss poor planning and expansion. Everything in that area can and will get flooded. The worst part is the city, state and developers knew this and still went ahead without properly designing the city for flooding.