A portion of Union Pacific Railroad’s (UPRR) Fort Worth Subdivision extends along the Brazos River near Eloise, Texas. This subdivision is important to UPRR in that provides a vital link between Dallas-Fort Worth and Houston and carries tons of freight each day. Any disruption in service could hurt consumers in two of the largest metro areas in the U.S.
In early 2017, UPRR officials noticed the migration of a specific segment of the Brazos River had accelerated 90 feet during an 18-month period and was now flowing 55 feet from the track. They reached out to Olsson to help stabilize the riverbank along a half-mile stretch of track. The river had been migrating toward the track since 1955, but it was getting dangerously close and the railroad needed a solution that would keep the track in operation.
We immediately went to work figuring out a permanent solution that would keep the line open and stop the river from migrating toward the track.
To understand the scope of the challenge, Olsson first completed geomorphic and geotechnical analysis of the river. We learned that in 1955, the river flowed more than 1,000 feet away from the track, and the 30-foot-high bank – which was near-vertical – was made up of compacted soil on top of a layer of sand near the flowline of the river. Over time, water had washed out the sand, causing the soil to fall into the river and wash away.
We used a combination of traditional topographic, drone photogrammetry, and bathymetric survey to determine the existing ground surface of the river bottom, vertical bank, and overbank area.
Before any work could be done, our environmental team secured a U.S. Army Corps of Engineers Nationwide Permit to repair uplands damaged by discrete events, allowing us to restore the damage and stabilize the bank.
The environmental team also discovered several threatened and endangered species in the project area, including Texas fawnsfoot mussels. Prior to excavation, representatives of the Texas Wildlife Department and our team conducted a mussel survey along the river bank. Mussels observed within the proposed area of stabilization were relocated.
Our civil engineers designed a riprap revetment along the bank. Our design called for the creation of a berm made of riprap on the toe of the slope of the river bank. Work began on both ends of the affected bank.
Reid Construction, the lead contractor, also excavated the bank back to make it more stable and secure. Approximately 75,000 cubic yards of riprap were used for the project, some of which was delivered to the site by train.
We also provided water resources analysis, floodplain permitting, bank stability monitoring, and construction observation.
Construction of the project was completed in January 2018.