On Flood Control, Dallas Better Think Nationally or Be Ready to Drown Locally

Categories: Schutze

SHZ_GetOffMyLawn_TitleImageV2.jpg
Man, talk about whistling past the graveyard. At yesterday's Dallas City Council meeting, council members Tennell Atkins and Delia Jasso asked good questions about the city's flood control plans, and City Manager Mary Suhm and her assistant, Jill Jordan, gave good answers. But it was all deck chairs on the Titanic.

Nobody gets it yet. Dallas is in for a major ass-whipping on flood control, because guess what? So is the whole nation.

American cities were built in the 19th and 20th centuries on the basis of certain assumptions about flood control. The assumptions are obsolete. We're in for less flood control, not more, at least in terms of man-made structures -- levees, dams and reservoirs.

The only kind of flood control that can fix what's wrong now falls under the rubric of land-use reform, as in, "Hey, man, get off that land you're on now, because it's gonna get hit by a bad flood, and there's not a damn thing we can do to stop it." Or, as I might be tempted to put it, get off my lawn.

trinityriver1908flood.jpg
The Trinity River, 1908
In The New York Times today is a flood control story that The Times doesn't understand, either. It's about rebuilding the Birds Point levees along the Mississippi in southeastern Missouri.

First off, just think about what happened there last spring. The U.S. Army Corps of Engineers came in and did to the town of Pinhook what the regular Army might do to a Taliban encampment in Afghanistan. They blew up the levees and flooded Pinhook off the map.

Well, they told everybody in advance. I don't want to make them look too bad. And actually, Pinhook only lost 30 houses, whereas if the Corps had not blown the levees the larger community of Cairo, Illinois, (population 3,000) upriver from Pinhook would have been swept down the river to the Gulf of Mexico.

Those are the choices these days.

Buried in The Times story is the real news: When the Corps came back to rebuild the Bird Point levee, they only had enough money to build it back to a height of 55 feet, fully 12 percent lower than its height of 62.5 feet before it got blown up. (These measurements are in relation to a river gauge near Cairo.)

I stop doing math at simple arithmetic. I have no idea know how to extrapolate that reduction in levee height to discover how much less flood protection it means for the surrounding territory, but it's less. Way less. And that's how things are going to be nationwide.

The Times doesn't get that. They think the story is about fixing the levees back the way they were. The story quotes a local official who goes unchallenged as saying residents in Missouri "were basically guaranteed protection from Congress to 62.5 feet."

Nah, I don't think so. Show me that guarantee on paper, will you? The corps does what it can. Local communities do what they can. But the assertion that anybody anywhere is "guaranteed" a specific level of protection is absurd.

Maybe they counted on that level of protection, and now it's gone. So that puts them in the legal political status generally known as "screwed." But I never heard of a guarantee that you can't get screwed.

There's even a line in the story, not attributed to anyone and placed in magic parentheses, that says: "(The Disaster Relief Appropriations Act, passed last month by Congress, may provide the money to finish the job.)"

I actually know who said that. The Tooth Fairy. In your dreams. The national flood control funding story is that there is a huge national funding shortfall for flood insurance, let alone capital money for flood works, and that shortage is not going away.

Let's bring this back home: If the Trinity River levee system in Dallas winds up getting built back to a lower level of protection -- say 12 percent lower -- that alone will kick off an earthquake in real estate values in the center of the city.

The corps, meanwhile, has been signaling in every way it can that the Trinity levees will not be built back to the level of protection thought to be in place before the levees were discovered to be no-damn-good in 2007. The levees will never be as good as people thought they were before 2007.

Of course, they were never that good, anyway, but having them officially not that good will deliver a body blow in terms of development value and insurance costs.

What council members Atkins and Jasso were asking for yesterday was a comprehensive briefing on citywide flood control efforts. Suhm said she'd do it. They're all right, as far as they went. We do need a citywide view of the problem.

But, look. What the Dallas City Council really needs is a nationwide, maybe global view. The Corps of Engineers has a task force working on this picture and putting it in context with flood control efforts worldwide. Our City Hall needs to get somebody from that outfit to come talk to them.

Hey. There's no use taking care of flood control in Pinhook if you're only going to find out later there's an even bigger problem in Cairo.

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flood control
flood control

this is amazing, i have lost words while reading this. super amazing! thanks for the share!

VijayB
VijayB

Speaking of flood protection, everyone in the government has conveniently overlooked (or deliberately put blinders on) the fact that on the South (or West) side of the levee system, there is a gap between the existing levee and where the new Cadillac Heights levee will begin.  You can see it quite clearly on p.5 of this presentation:  http://dallascityhall.com/comm...

The gap is at Moore Park, and during the development of the Trinity River Corridor no one at the Corps of Engineers or at the City of Dallas would explain what would happen to the folks who live on Rockefeller Blvd, and Ventura Dr., adjacent to Moore Park.

Levees.org
Levees.org

Thinking nationally is the way of the future, apparently.  The introduction of the LSAC system - Levee Safety Rating Classification System - is an important development.  This appears to us a pre-emptive first strike in re-estabilishing an entity that removes control from Congress on how water projects are prioritized and funded.  We believe that while this gives the Corps of Engineers a lot of control, it also removes ‘politicizing’ of how water projects are chosen.  

Heywood U Buzzoff
Heywood U Buzzoff

Jim,  yesterday you wanted the ultimate urban park.  Now you want flood control.  Can't have both.  We need a good flood or two and then you can go spelunking in the down town tunnels, surf Deep Ellum or 'punt the Nutria'.  So make a choice, flood control or urban jungle, and let me know when the solar powered water taxis area ready!

Perry Moore
Perry Moore

Please put down the gun, Mr. Schutze. I just came by here to compliment you on a well written article. We have all been trying to bend nature to our collective will for some time. Obviously, we have bitten off more than we can chew.

Paul
Paul

Well, if there is another flood crest similar to this one at Cairo and Bird's Point, guess what ... the levee at Bird's Point will be dynamited again.

As far as the Trinity Floodway not offering the same level of protection prior to 2007 all you have to do is look at ALL of the development upstream.  The runoff rate has increased.  As a result the peak flowrate has increased from storm events of the same intensity.

My recommendation would be to require detention basins upstream of the narrows at Downtown Dallas in order to reduce the runoff rate.

Harris County and the City of Houston have been quite successful over the past twenty years in reducing flooding by using this method.

Marc
Marc

Paul, you make some excellent points that merit serious consideration, and I would just like to point out that the Trinity River, as it exists today, is not the original river bed. It was diverted many decades ago when somebody had a wet dream about making Dallas a seaport. One solution would be to dredge, widening and deepening, the river bed to allow it to convey more water downstream. At the same time, our levee system is in dire need of restructuring to a new height. I am guessing that an additional ten to fifteen feet in height would be adequate for all but the very worst floods.

Unfortunately, all such solutions cost billions of dollars that are just not available, but if talk would resolve problems, then you can bet that Mary Suhm would be a problem solver extrordinaire.

Regarding the issue of rebuilding the levees at Pinhook, if they are rebuilt 12% lower than originally constructed, then Cairo will not be in as much danger as before, but Pinhook and surrounding areas will be in deep doo-doo the next time Old Man River floods like it has done several times in recent years!

Every action has an equal but opposite reaction. Building levees that protect one area will inevitably adversely affect other areas above and below that levee system. Ain't it a bitch how Mother Nature works?

Paul
Paul

Thanks Marc .... best check your history though ... There were severe floods in 1910 and 1912 and these are the current "flood of record" used for the design basis.  (See the picture in the story.)

The predecessor to today's current levee's were built in the late 1920's in order to be able to develop the bottom land upstream of Downtown Dallas.  The USACE reinforced this levee system after WWII since it was, Surprise! Surprise!, inadequate to protect the reclaimed bottom land from flooding.  The DPL has some wonderful aerial photos of the original levee system being built.

The river channel was originally on the Dallas side and the Stemmons levee building snatched the land away from the Oak Cliff side of the river and put it on the Dallas side of the river.

That nice little lake in front of the Mobil Building on Stemmons is part of the original river channel.

More dirt was moved in building the Trinity Floodway than in building the Panama Canal.

Many people also don't realize that the Trinity Floodway was built down just as much as it was built up.  There were many sand and gravel pits in the Trinity Floodway in the 1920's and 1930's.  The Trinity Floodway has silted in over the years and is one of the reasons why the capacity has been reduced.

The Trinity being a waterway for barge traffic is an entirely different story.  If you look at the Trinity by using Google Earth you can see the remnants of many of the locks and dams that had been built.  There are several in SE Dallas County today.

Just remember, they are levees not dams.

PlanoDave
PlanoDave

Does Calatrava design detention basins?  Or are they solar powered with fancy lighting?

Paul
Paul

Does Calatrava design detention basins? ---> Only overpriced "designer' ones suitable for a fete of the rich and powerful to show how civic minded they are.

Or are they solar powered with fancy lighting? ---> Only in the brochure for the bond program.

Tim Covington
Tim Covington

This brings to mind something my father taught me. My father was born and raised along the Mississippi River. Who taught me to look for signs that a property could has flooded in the past. And, he taught me to not buy property like that. 

Unfortunately, to many people have not learned or forgotten that lesson.

The Royal Wii
The Royal Wii

Your father sounds like a wise man.

If you want to predict the future, look what has happened in the past. That, or pony-up the new premiums and learn to swim.

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