Before-After Pics of 2024 Tree Lane Bridge Repairs

11/3/24 – The latest round of repairs to the understructure of the Tree Lane Bridge in Kingwood has been completed.

In recent years, flooding, erosion from severe storms, stream migration, and insufficiently mitigated upstream development had jeopardized the integrity of the bridge next to Bear Branch Elementary. Approximately 600 children attend Grades K through 5 at the school and dozens of school buses routinely cross over the bridge every school day.

Before Photos

The four pictures below show the starting point.

Tree Lane Bridge during May 2024 flood — *Imelda flood almost overtopped the bridge* *and backed water up.* *Photo by Chris Bloch.*

Tree Lane Bridge Before Start of Round 2 Repairs — Looking upstream at downstream side of the bridge. Water pressure created a jetting effect that undermined the support structure and eroded the area downstream. Downcutting exposed water line and utility cable.

*Closer shot shows the power of moving water. Storm drain outfall (right) was pinched off by debris* *that broke away.*

Tree Lane Bridge damage — *Stormwater had also eaten away the concrete bed that tied supports together.*

After Photos

Compare the next five shots taken on 11/3/24.

*Upstream is left. Note how stream meander over time has Bens Branch approaching the bridge from a 45 degree angle now.*

Meandering streams can impact bridges in a number of ways, including:

Altering flow characteristics: A meander at the upstream of a bridge can change the flow characteristics at the bridge’s inlet and outlet.
Reducing bridge capacity: A meander can reduce the amount of water a bridge can pass during a flood.
Creating channel instability: Channel instability near a bridge can increase the risk of bridge failure during a hydrologic event.

Meandering streams are characterized by their sinuous, snake-like channels. Meanders move sideways and downstream over time, which can create challenges for maintaining bridges and roads.

However, these repairs should improve safety …. at least for a while.

*Looking upstream. Note new storm drain outfalls surrounded by concrete on the left and right.*

*Note how the side slopes change from 45º to 90º about three feet above the bottom of the channel.*

The stream bed was previously at where the wall angle changes. The area between the 90º walls represents additional carrying capacity (conveyance) for the channel under the bridge.

Also note, in the picture above, the addition of at least five new rounded piers to increase support for the bridge’s road bed. The old piers are square.

*Storm sewer outfall is now at an angle.*

According to ChatGPT, “Storm sewer outfalls are often angled when they enter a stream to help manage the flow of water and sediment, reduce erosion, and improve the overall stability of the stream bank.”