The Easy Answer to the Trinity River's Levee Problems? Just Blame Katrina.
After Mayor Tom Leppert announced the need to pony up $29 million to study Dallas's levees resulting from "unacceptable" ratings by the U.S. Army Corps of Engineers, a frustrated city official essentially blamed Hurricane Katrina for everything. "I think the corps is CYA'ing in the worst way," I was told.
Indeed, the 53 levee breaches flooding 80 percent of New Orleans forced the corps to develop new testing standards, which is why Dallas slipped from receiving "excellent" ratings on its levees to a point where no one knows exactly how much work or dough it's gonna take to ensure downtown Dallas won't become the next New Orleans.
One of the more significant concerns is a layer of sand discovered in the floodway during the installation of a pier for the Margaret Hunt Hill Bridge -- one of two (maybe three, depending on funding) bridges designed by Santiago Calatrava as part of the Trinity River Corridor Project. Representatives from the corps watched last year as the city's contractor drilled a hole 90 feet into the floodway and liquefied sand rushed up, destabilizing the drilling rig and causing such a clusterfuck that the casing used to mitigate the damage was left behind as a permanent part of the floodway.
Sand can have devastating effects on the levees' integrity, and while the pier incident occurred near the middle of the floodway, sand was also found underneath both levees -- the worst place to find it. Naturally, both Schutze and I were shocked that the corps didn't know the sand was there, especially since they built the levees more than 50 years ago.
Like Jim, I too was "aquiver with fascination" when he received soil boring results from the city of Dallas showing a layer of sand exactly where the drilling for the pier occurred. The city provided the results to the corps, whose Trinity River project director, Kevin Craig, told me that he didn't know "the nature or the extent" of the sand and said the corps authorized the Margaret Hunt Hill Bridge project without "all the geotechnical data."
When I contacted Craig about the boring results, he mentioned our previous conversation. "First of all, after reading your article last time, I wanted to make sure that anything I said was not insinuating that TxDOT would ever build a bridge without geotechnical data," he said. "What I was trying to say is the geotechnical data that was done was done for TxDOT's design purposes, which is different from what we need for levee purposes."
To be clear, the story did not mention the Texas Department of Transportation at all and was titled: "Corps Approved Bridge Without Geotechnical Data, Still Trying to Solve Sand Mystery."
So I told Craig that I had a document from the city of Dallas dated August 23, 2006, showing a layer of sand about 25 feet below the surface right where the sand came a bubblin' up.
"Just remember that our major concern is in that area about 50 feet [from] either side of the toe of the levee. Just because there is sand out in the middle of the floodway does not necessarily indicate that it is under the levee area," he told Unfair Park. "The only borings that we had from the submittal of the bridge, there was only one boring I think that was within 50 feet of the west levee, and it didn't show sand of any concern. And so that's why, we, at that time, our processes and policies didn't require extensive geotechnical testing as it now does. But we did require that our people would be present when the piers were installed within that levee template. And in about April of '08 was when the first pier was installed within that levee template. And that's when the sand was hit that raised our level of concern."
Pier 6: Enter Sandman.
But wait. The city provided the corps with the boring samples. The sand shouldn't have been a surprise then, right?
"The borings that they provided to us showed sand at different levels within the floodway itself, but we didn't have any data within that 50-foot zone if you will that showed sand," he said. "When they were actually doing the drilling of that pier right within the levee -- it was pier 6 -- and they had the problem with the casing, that was well away from the levee, and we didn't even know about that until the time we were out there while they were drilling in the levee."
Just to confirm, I asked if he's seen the document I'm looking at. He hasn't, but he assured me that the geotechnical staff has seen it, and he again stressed that a layer of sand 25 feet below the surface stretching through the floodway doesn't necessarily mean that there are any problems with the levees. I asked: Wouldn't that be a concern that would make you apprehensive about not doing exhaustive samples before allowing piers to be drilled for a massive bridge project?
"Well, again, we're primarily concerned with the area around the levee. The boring that we had within that vicinity did not show sand. It's not unusual where sand seems to be heading toward a river channel ... it doesn't mean we know the horizontal or vertical extent of that," he said. "Again, our processes at that time did not require extensive geotechnical testing, but we did take the precaution of having our people out there on site when those piers were installed in the levee."
Craig said TxDOT is in the process of identifying the characteristics of the sand and surrounding soil to determine whether it will need to add construction features to the project. I wondered if anything in the findings would cause the corps to retract its authorization.
"Our role is going to be ensuring that what they are proposing for mitigation does do what they say it's gonna do," he said.
So there's nothing that could be found leading the corps to conclude that building this bridge is suddenly an awful idea?
"That's very speculative," he said. "I wouldn't ... we have to see ... I don't anticipate that. We just have to see what the extent of remediation is required, if any. It's just going to depend on what the characteristics are in that particular area."
But can the corps renege on its approval if something is found that it doesn't like?
"I would just say I don't anticipate that."
To summarize, the corps authorized a bridge project without all of the geotechnical data that would have piers penetrating the levees and the floodway, assuming it would be fine if its people were out there when the piers were drilled. The corps wasn't concerned at all with any of the penetrations into the floodway, only ones within 50 feet of the toe of the levee. But Craig says the corps only saw one boring in that area, which didn't show any sand.
Yet there was sand, and lots of it. And the corps knew it was there -- at least the portion running along the middle of the floodway because the city documents said so. But again, no biggie because it wasn't near the levees. However, it was a big deal because of the aforementioned disaster that occurred during the installation of pier 6 and subsequent discovery of sand underneath both levees.
The big excuse for this mess? Standards have changed since Katrina.
So, yeah, the corps is covering its collective asses in the worst way as I was told, but this great news. I have no idea what will happen with the levee study or the Margaret Hunt Hill Bridge, but the tragedy resulting from Hurricane Katrina will hopefully ensure that whatever gets built won't compromise the safety of downtown.
And remember how the city said the Trinity River toll road and the levee reports had nothing to do with each other? Looks like the Federal Highway Administration thinks the two are very related. I tried to get a comment from Mayor Tom Leppert last week at a press conference for the U.S. Hispanic Chamber of Commerce, but he literally ran away from me, and my calls to Assistant City Manager Ramon Miguez have not been returned.
Perhaps Leppert and Miguez should come up with a CYA plan of their own: ditch the toll road and blame it on Katrina. Heck, it's better than the alternative: watching the road die slowly, leaving no one left to blame when the music stops other than the city and those pushing it despite overwhelming evidence telling them otherwise.
Get the ICYMI: Today's Top Stories
Catch up on the day's news and stay informed with our daily digest of the most popular news, music, food and arts stories in Dallas, delivered to your inbox Monday through Friday.