Corps Approved Bridge Without Geotechnical Data, Still Trying to Solve Sand Mystery

After the U.S. Army Corps of Engineers released its report on the city's levees, we were baffled to learn that construction on the Margaret Hunt Hill Bridge would continue, especially since drilling a concrete pier for the bridge into the floodway resulted in the troubling discovery of sand and the botched installation of the pier.

So we asked Kevin Craig, the corps' Trinity River project director, that very question: How the heck is construction moving forward?

"I guess it's the definition of moving forward," Craig tells Unfair Park. "Moving forward means that they are moving forward with the analysis, investigations and the design for how to remediate things to ensure that bridge doesn't cause adverse impacts to the levee."

Ah, yes -- remediate. Has anyone found a legitimate way to accomplish that or is it still a work in progress?

"We feel like there are ways to mitigate it," he says. "The investigations and analysis will tell us how to do that."

Let that sink in. The city wants a suspension bridge and toll road inside its flood-control system so badly that it's asking the corps to investigate and analyze ways to lessen the impact of inserting massive concrete piers into the floodway, which adversely affect the integrity of the levees.

We were also dying to know why the corps didn't know about the sand since they rebuilt the levees in the early 1950s. Isn't there data, analysis or core samples somewhere that would have tipped them off?

"That's part of what we're doing is going back and looking at all the existing data that was done, was prepared or used in those designs," he says. "I don't know the full answer to that question until we go back and look and see all what was done."

Seriously? So was the corps totally oblivious to the sand or did they just underestimate the problem?

"As far as I know, Sam, we didn't know the nature or the extent of that sand, and we still don't," he says.

But the corps had to have some core samples before the drilling work was done on the bridge, right? Right?

"We didn't have all the geotechnical data," he says. "We approved that with the understanding that we would have geotechnical people on site as they were drilling, and that's where we really found the sand."

Craig also says the corps has not determined whether the soil from the Trinity lakes will be acceptable for the levee raise, claiming that drilling and testing is still underway.

As Jim pointed out yesterday, the corps could be held liable for approving non-flood-control projects that cause flooding, so we asked Craig if the corps is concerned about being held accountable for approving projects like the Trinity River toll road.

"As of yet, that has not entered into the discussions that we've had," he says.

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