Tag Archive for: FM1960 Bridge

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.

Most of the flooding during Harvey happened above the FM1960 bridge on the East and West Forks.
The bridge is mostly a causeway. It has two small openings that total 1700 feet.
The two openings restrict the flow compared to other bridges and create a backwater effect.

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.

Looking north toward Kingwood’s Kings Harbor. The West Lake Houston Parkway bridge is on the left. Photo taken two weeks after Harvey. In the foreground, sand now reaches the tree tops and is virtually as high as the bridge itself. Water used to flow under the bridge and through the area in the foreground during floods. Now it is forced north.

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?

Note the different shades of brown near the FM1960 Bridge and how the flow within those colors is disrupted by the bridge, especially by the smaller eastern opening. Satellite image from 8/30/17 DURING Harvey.

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!

Satellite image from 12/30/2014 shows purple/brown effluent coming from Luce Bayou. Note the three distinct sediment colors in this photo: light brown in the West Fork on the left, medium brown from the East Fork at the top, and dark brown from Luce Bayou on the right.
Most recent Google Earth image from 2/23/19 shows that water coming from Luce Bayou is more normal in coloration now. Construction on the Interbasin Water Transfer Project is required to be complete this month. Let’s hope that’s the last we see of that purple stuff.

Posted by Bob Rehak on 6/14/2019

654 Days After Hurricane Harvey