Save Money with This Long-term Fix for Scour Problems

Scour poses a large threat to the stability of any structure that is partially or entirely underwater. It may develop slowly over time, or be brought on quickly by an intense rain event or seasonal flooding. In some cases, such as along a shoreline, scour can be very evident. In others, scour can go unnoticed for an extended period of time. Whether it is taking place around the footing of a bridge pier, along the base of a sheet pile wall, or along a tailrace on a dam, scour may not be evident until the structure begins to show signs above the water. At this point, the structure is beginning to fail and repairs must be done soon to avoid a total loss of integrity. Repairing scour and erosion issues that may be going unnoticed in any location is vital as it will save a lot of money in the long run, and extend the life of the structure.

Lock and Dams, bridges, pipeline crossings, and barge terminals are all examples of water-based infrastructure. Ensuring that these structures maintain their integrity is essential to their continued operation, however water-based infrastructure presents an added challenge because a portion of the structure is underwater.

There is a lot of buzz around the president’s infrastructure plan lately. It is clear that everyone wants better infrastructure, regardless to which party an individual may belong. The biggest challenge to getting what everyone wants is funding, and making matters more difficult, the allocation of this funding is another source of disagreement. As a contractor that provides construction services to owners of infrastructure, it is clear that the waterways are suffering the most from lack of investment.

According to the United States Department of Transportation, underwater scour is the leading cause of bridge failure, ahead of collisions and overloading. Scour is the erosion or removal of a streambed or bank material from bridge foundations due to flowing water. As many bridges sit over water, the potential dangers of scour cannot be ignored. There are many solutions to scour problems. However, there are two options that we find the most effective.

As we begin the month of November those of us that work in and around the water have to start planning for seasonal changes and the accompanying cold weather challenges.  Water temperatures begin to drop rapidly, sometimes over a degree Fahrenheit (F) per day.  This presents a whole new bunch of logistical and safety risks. 

On June 20th, the U.S. Coast Guard published the final version of 46 CFR Subchapter M, a long
awaited revamp of the laws that govern the inland waterway system.  Over the next 11 years, all commercial towing vessels that are longer than 26 feet in length will have to comply to a set of new
rules and regulations.  

Traditionally when it comes to installing sheet piling around a bridge pier or along an embankment we think of steel sheet piling.  Steel sheet piling are the most common, and have been one of the most effective methods of installing a deep foundation.  They have a long history of providing a robust barrier through shaped, interlocking sheets that can last for 75+ years. 

When considering our infrastructure often times our inland waterways are forgotten. What most people may not know is that barge transportation is as important as railways or highways.  Barges are responsible for moving more than 60% of grain exports throughout the United States.  Barge transportation is a very efficient mode of moving bulk materials such as grains, coal, and other commodities.  As stated by the National Waterways Foundation 1,750 short tons of dry cargo fit into one barge which is otherwise 16 rail cars or 70 trucks.   

            Hydrographic surveys are a very effective way to map the bottom of a river, lake, or other water body.  By using some of the latest technologies a 3-dimensional model can be developed to show contours, obstacles, scour areas, and large debris.  Even in the most turbid conditions, a hydrographic survey done correctly can be very effective.