City Begins Tree Lane Bridge Repairs

This morning, City of Houston contractors began clearing access points for the Tree Lane Bridge repairs in Kingwood next to Bear Branch Elementary where more than 600 students attend classes.

The City announced the kickoff of the project on February 21, 2024, but work actually started today.

Extent of Damage

This is actually the second round of repairs. The City made some rudimentary efforts in 2020 that ultimately proved ineffective. Four years later, erosion under the bridge is more extensive now than then.

I took all the pictures below on 4/7/24.

The forensic report blames the damage on “failure of riprap.” Riprap is boulders placed in the stream designed to reduce erosion by slowing the flow of water, breaking it up, and providing a protective barrier.

However, the forensic analysis indicates that water flow in Bens Branch undermined the rip rap.

Soil beneath riprap can be eroded if the rock was just placed on top without any buffer between the layers such as a geotextile fabric or smaller riprap (crushed stone).

In this case, erosion removed more than a foot of soil behind the concrete walls, under the base, and under the existing riprap.

You can see from the exposed utilities that the creek has downcut. This downcutting extends several hundred feet upstream of the bridge. And that’s part of the problem. It allowed water to get behind and under the existing channel linings.

Construction plans call for:

• Removing all the existing material under the bridge and on the sides of the banks
• Installing a new concrete channel (bottom and sides) that will maintain the flow line of the stream.
• Repairing outfalls.

The engineer’s report claims the proposed U-shaped channel will hold the current side slopes of the bridge and allow for the drop in the flow line.

For More Information

See the Report of Findings, construction plans, and the City’s official Engage Houston web page.

For pictures of how the bridge looked after the last round of repairs, see this post from 3/31/2020.

For pictures of a flood responsible for much of the damage, see this post from 1/29/23.

A Silver Lining

The damage to the Tree Lane bridge has been so rapid, that it occurred twice within the time many Bear Branch students attended the adjacent elementary school. Perhaps it will inspire curiosity about flooding among some of these students, spur them to pursue engineering careers, and perhaps prevent such dangers in the future.

Safety Precaution

The City hopes to complete the Tree Lane bridge project sometime this summer, weather permitting. Please observe traffic warning signs, cones and flags for the duration. And keep curious children away from heavy equipment which will be maneuvering in tight spaces with limited visibility.

Posted by Bob Rehak on 4/9/2024 with help from Chris Bloch of the Bear Branch Trail Association

2415 Days since Hurricane Harvey