The Limits of Mapping Flood Risk; Original Beaver’s Takes a Summer Vacation

Photo: Russell Hancock via Swamplot Flickr Pool


13 Comment

  • The floodplain article is a joke. The 100 year floodplain maps are for riverine floodplains or in coastal areas for storm surges.

    The maps do not cover street flooding due to sheetflow.

    Homes built in the 50’s and 60’s with slabs set at street level will flood in Houston. It was bad design then as it is now.

    If a map did take into account street flooding, flood insurance rates would skyrocket. And let’s be clear, flood maps are purely for setting insurance rates. That’s why the are officially called Flood Insurance Rate Maps (FIRM).

  • Re the urban edge article, I was right. After four days of arguing the most stubborn developer engineers on the planet, I was proven correct. They said it was “dangerous: to re-evaluate the flood plain. Rather, it is dangerous not to.

  • The NFIP is a creation of Congress meant to insure against a peril which the private insurance industry refuses to insure against. The reason private insurance refuses is because there is no actuarially sound method to do so. Effectively, federal flood insurance is not pure risk insurance but actually a type of social insurance. To move the conversation forward on flood insurance reform, that fact has to be acknowledged first. By properly characterizing it as social insurance, we can start talking about how much more people in flood prone areas should pay.

  • Don’t take the bait guys.

  • The study area cited, the Armand Bayou watershed, has historical differential subsidence, due to groundwater removal from water wells. In the upper part of this watershed, subsidence has been up to 7 feet, while in Clear Lake the subsidence had been 4 feet.
    Certainly, this would not be the only cause of structural flooding, but the study should include this very significant factor. Another good example of this phenomena, is Jersey Village, which has experienced severe structural flooding due to subsidence. A visit to the Houston GIMS website, turning on the floodplain maps, indicates the large extent of the 500 year (0.5%) flood risk in these areas, again significantly (not solely) due to subsidence. Houston, for this reason, is turning to surface water sources for it’s potable supply.

    The intent of the floodplain maps is to indicate flood risk, whether riverine or not, based on topographic elevation and the capacity/flow of the downstream conveyance during an extreme event (0.5% event minimum).

  • All of you are aware or should be that the flood plain is used by the city permiting office when deciding how much stormwater runoff a development is required to have. If you aren’t aware, seriously turn in your engineering license or stop commenting on subjects where your are totally ignorant. This article is definitely on point and useful.

  • *floodplain

    Uh, it is one word. Mr. Engineer.

  • Thanks Bocephalus – your priorities are really on point. This just illustrates how difficult it is dealing with drainage engineers – can’t see the forest for all those trees. A drainage engineer is a dropout from a mechanical engineering program. It’s no wonder these idiots can’t get anything right.

  • Subsidence was a contributing factor to the Alison disaster at TMC, as I recall.

  • Ha, sounds like flooding isnt all you are tired of. KJB434 pretty much nailed it already. What, you are telling me, maps created by man to predict the future of nature, are not 100% accurate? The city permitting office gets things wrong, well shoot. Developers are greedy, stop the presses. But yea, got to agree with you on them drainage engineers. They went and got agree to find out that stuff, it rolls down the hill.

  • Wow those Aldis are practically brand new, and already being remodeled? I’m glad they’re expanding their produce section with what looks like organic produce. Even Target seems to be expanding its offerings in that regard. The grocery business is pretty cutthroat, I know, and I always figured a completely organic-only Aldi would be a very formidable entry into the arena, much moreso than would a regular Aldi.

  • Boc – the issue is that flooding is caused by recent man made construction developments not just nature. Please try to keep up.

  • ^ you needed an article to tell you that? Better tell Noah to get the Ark ready, development doesnt look like it is stopping in Htown.