Sounding the Kansas River
When you think of floating down a river, does it conjure up images of Huckleberry Finn and Tom Sawyer and their adventures? Or maybe sitting on a raft as the lazy currents carry you?
Although our project may not be full of adventures nor was it a lazy float trip, it posed interesting challenges. It all started on a spring day when a member of GBA’s environmental group was performing a scour analysis on the DeSoto Bridge that spans the Kansas River. The team found that one of the bridge piers was scour critical which could compromise the integrity and stability of the bridge structure. This issue needed to be addressed by conducting borings deep enough to determine subsoil conditions. That required bringing in a barge.
The Kansas River, like any body of water, has various depths and to find out what the exact depths are, a bathymetric survey was performed to measure the water depth at various places along the river, also known as sounding. This barge required at least four feet of water depth to get down the river safely, so GBA’s survey crew was tasked with performing the survey to ensure the barge had enough clearance.
From the start the project encountered challenges. The first was finding the equipment to conduct the survey. Since GBA only performs this type of survey occasionally, the sonar equipment had to be rented and shipped overnight from Louisiana. When the equipment arrived, a two-man survey crew made their way to the river to survey a ¾-mile stretch.
Once on the river, the crew realized the water was shallow and had several sand bars. This made it difficult for the small boat they were using to get through the water so they knew this would also pose challenges for the barge. After two days of data collection, the information was used to create a map showing the various depths. The river also concealed bridge piers from the old DeSoto Bridge that had been demolished several years ago. Finding old plans of the bridge, the crew was able to mark where the piers were on the map so the barge could maneuver around them.
Finally, the data was transferred to the barge to determine if it could get down the river. The date showed the barge could make it down the river, albeit a tight fit. Terracon, a geotechnical firm and barge owner, took the barge to the river only to find they would not be able to use the boat launch closest to the piers. Farther down the river, they found a spot, and the barge set sail.
The barge was able to get through the water and the borings were conducted. The findings are being reviewed and will determine if the pier is still scour critical.
This project offered a unique experience for the GBA survey crew. And although they did not find any robber’s gold, they did have an adventure sounding the Kansas River.
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