New Presentation Looks at Role of FM1960 Bridge in Harvey Flooding
Charles Jones, a Lake Houston Area resident and business man, has developed a presentation that examines the role of the FM1960 bridge in Harvey Flooding. The small openings in the bridge, he says, constrict the flow of floodwaters, much like sand gets pinched and backed up when moving through an hourglass.
You can download and review the entire presentation here. It will be stored permanently under the Other Flood Mitigation tab of the Reports page on this web site.
Summary of Jones’ Theory
The following three slides sum up the heart of Jones’ theory.
Discussion of FM1960 Theory
Jones’ presentation is a deliberately “high level”, simplified discussion targeted at a general audience. Parts of it seemed a bit OVERsimplified at times.
For instance, at one point he describes the FM1960 bridge as the cause of sediment build up in the mouth bar area on the West Fork. But if that’s the only cause, why isn’t there a similar build up on the East Fork?
Another example: he describes the West Lake Houston Parkway Bridge as 3700 feet in length. That’s true. But so much sand is stacked up on the downstream side of the bridge that it effectively narrows the opening. See sand in the treetops below.
However, put those observations aside for the moment and ask two simple questions:
- Are the principles behind Jones’ theory generally true?
- Are there any direct observations available that support the theory?
The answers are yes and yes.
“There’s Always a Bottleneck Somewhere in Every System”
I had a client for 35 years that made plastics. The company was one of the largest and most respected in the business. They built plants around the world. A process engineer in that company, whom I highly respected, once told me, “There’s always a bottleneck somewhere in every system.” The FM1960 bridge is ONE of those bottlenecks.
Other Support for Theory
But what about the direct observations?
- A FEMA damage map shows that most of the damage around Lake Houston happened above the FM1960 bridge.
- Anecdotal reports from residents indicated the water was higher above FM1960 than below.
- A Texas Water Development Board difference map shows huge sediment build-ups above the dam, indicating that the water is slowing at this location.
- A Google Earth satellite image taken DURING Harvey shows water swirling above the bridge looking for a way to get downstream. In the photo below, see how the bridge disrupts the different colors in the flow.
So pardon the pun, but I think Jones’ theory holds some water. It certainly merits further investigation. I would certainly like to know the answers to the following questions:
- Did someone actually measure the difference between the high water marks on each side of the bridge during Harvey?
- If so what was it? Can the backwater effect of the causeway be quantified?
- Is there photographic evidence of any difference?
- If the backwater effect is significant, how much would it cost to modify the bridge? Would the benefits justify the cost?
Thank you, Mr. Jones, for bringing this matter to the public’s attention. You’ve made a valuable contribution to our understanding of Harvey.
And On a Side Note…
What’s that nasty brown stuff flowing out of Luce Bayou on the upper right in the photo above? At first I thought I might be the shadow of a cloud on that particular day, but it shows up consistently in other photos. See below, for instance. It starts about the time construction on the Luce Bayou project started. That’s the project designed to bring water to Lake Houston from the Trinity River. Mmmmmm!
Posted by Bob Rehak on 6/14/2019
654 Days After Hurricane Harvey