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Allison’s floods could have been worse

Not sure how useful this actually is, but this Chron article discusses some alternate scenarios to Tropical Storm Allison, which flooded out most of Houston in 2001. Apparently, we got off lighter than we had to, since the areas that received the most rain were less populated than some others, and the nearest bayous were best equipped to take it. Hard to say if there are any lessons to learn from this, since TS Allison was such a freak occurrance, but it’s interesting reading nonetheless.

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10 Comments

  1. HWRNMNBSOL says:

    I did a lot of the flood control engineering work for M.D. Anderson. I recently stopped consulting for them and started working directly for the hospital, which has caused me to take an even closer look at the effects of Allison on the Medical Center.

    What I’m finding is that M.D. Anderson really did get lucky. They had a lot of good stuff in place that helped them, undeniably, but the thing that really saved their bacon was that they had a new building getting constructed on their north side, and at the time of Allison they had just completed digging the pit for the substructure. This means that M.D. Anderson effectively had a huge retention pond on their north side that normally they wouldn’t have. This, more than any other single factor, explains why M.D. Anderson weathered the storm better than any other major institution in the Medical Center.

    So, we’re back to the drawing board. We have applied for FEMA funding and have received authorization on many millions of dollars to do the same things other people are doing: patch up flood control barriers, raise critical equipment, and do everything else you need to do to stay minimally functional in the event of a terrible storm.

    Meanwhile, the Harris County Flood Control District is quietly going about doing what they should have done long before Allison: widening their water conduits to increase drainage rates. A major widening of Braes Bayou is scheduled to happen in the next few years; the bridge over the Bayou for the new Metrorail was build with an extra long span to accommodate just such a project. The HCFD is keenly aware that dealing with high floodwaters is certainly The Medical Center’s problem, but it shouldn’t be their responsibility; it’s the county’s job to make sure water doesn’t rise that fast in the first place. They have major egg on their faces after Allison, and they’re working like crazy to keep such a fiasco from happening again.

  2. Um… Aren’t there roads and housing along Braes Bayou? How can you widen it?

  3. Pete says:

    By only widening it those 20-30 feet before it actually runs into the sidewalks, would be my guess.

  4. Ginger says:

    Having lived for a significant portion of my mumblesomething years as a Houstonian along the Braes Bayou corridor (a couple of them right on the bayou), I wouldn’t be surprised if some of the residences between Braeswood and the bayou near the loop are eventually condemned and the bayou widened into areas where there is now housing.

    One of the things the article confirmed for me is that we have to do more flood control planning on the west side. “Let them drink bayou water” is no longer a viable option for flood planning. If you’re not willing to plan drainage for it, don’t build it.

    Another thing it confirmed for me was “thank $DEITY for pier-and-beam”, even though I’m convinced that under some of the scenarios, we would have flooded even with 18 inches of ground clearance.

    That was a scary story.

  5. HWRNMNBSOL says:

    Owen asks:

    Um… Aren’t there roads and housing along Braes Bayou? How can you widen it?

    The short answer is: I don’t know. I have only had dealings with this project where it intersects my work, and that’s the stretch of Braes Bayou along the south side of the the Medical Center.

    Within that area, roads and structures are indeed being moved. For example, a fire house is presently located on Fannin on the south bank of Braes Bayou. A brand new fire house is under construction about one block south and on the other side of the street. One presumes that once the new firehouse is complete, the old one will be demolished.

    Generally speaking, within the area in question there really isn’t all that much that backs right up to the bayou. There is a large setback in the form of green space on the south side of the bayou for some reason that I don’t fully understand (there certainly isn’t any such setback on the north side) that sure looks like another n yards could be carved out.

    It’s also possible that some deepening of the bayou will be attempted, or possibly changing the shape of the profile to accommodate more volume. I don’t know what the flood control people have in mind, nor do I know exactly how they’ll propagate the widening all the way out to the Ship Channel. Let’s hope it’s a smart idea, whatever it is.

  6. Charles M says:

    As to the maps the Chron and the flood control district put up….

    By leaving out the major streets, the Chron made it impossible to tell which areas were actually at risk.

    The flood control district, on the other hand, had the maps up Sunday (the Chron said they would be up Monday) but they were so small and blurred, it was equally difficult to determine locations.

    As best I could tell, my residence (Dairy Ashford at Bellaire) might have been at risk. Couldn’t tell from the maps.

  7. elizabeth says:

    Ginger,

    When you say “west side,” just exactly where do you mean? I’m wondering if I’m included in that section of town; or am I too far west to be of concern?

    Just curious.

  8. Ginger says:

    When I say west side, I mean out to Katy. If you pave over everything out there, where does the runoff go? Into the drains and ultimately the bayous.

    The development of what used to be Andrau airport worries me. There was a lot of green space out there and now it’s all homes and shopping centers. I don’t know what the developers are doing in the way of detention ponds and the like, but if they’re standard Houston developers the answer is “not much”.

    I don’t have a lot of faith in the Army Corps of Engineers or the Harris County Flood Control District to solve this problem. Houston is run for developers and by developers–remember MayorBob?–and without somebody enforcing a requirement that new subdivisions have adequate drainage/retention/flood control measures, no developer in his or her right mind will do it. It simply costs too much.

    One of the law partners in the firm I used to work for was heavily involved in flood control issues. I learned a lot about flood control from him; most of it scared me.

  9. HWRNMNBSOL,

    I suppose it could be widened in that area — I’m just not sure how much extra flood protection we’d get from such a small-scale change, and if the bayou were widened further down, then you’d be taking out entire complexes and either North or South Braeswood.

  10. sajida mawani says:

    y are some floods bworse then others explain that but in a way little kids can under stand
    thank you sajida mawani