Dredging is the process by which sediments and debris are removed from the bottom of shipping channels, rivers, harbors, and other bodies of water.
It is a necessary practice in waterways worldwide. The means by which sand and silt are carried downstream, known as sedimentation, eventually fills channels and other waterways creating a situation where navigation becomes difficult. Dredging targets the maintenance or increase in the depth of navigable waterways to ensure the uninterrupted commerce of tugs, tows, barges, and ocean-going vessels. These vessels require a designated amount of draft so as not to run aground. This water depth requires the need to increase as the size of ships that are contracted increase. Since the majority of goods imported into the United States are transported by vessels increasing in size, dredging is crucial to the nation's economy. As the depth of a shipping port increases by each inch resulting from dredging, it translates to larger vessels transporting additional millions of dollars of cargo moving through the port. The weight of a ship will increase as more cargo is carried, as a result it will sit lower in the water and require more draft. With the slightest decrease in the depth of a waterway, a ship to will be required to reduce the amount of cargo onboard. Therefore, deeper water accounts for increased cargo. Also, this results in fewer trips required to transport goods to market. By reducing transportation costs, it also reduces costs to consumers, as well as increases vessel traffic safety and benefits the environment.
Testing dredged materials is required to ascertain contamination levels and the most prudent method of disposal, so as not to allow dredging these materials to pose a detrimental impact on the environment. Improper disposal of these contaminated materials in the marine environment can result in deterioration of the ecosystem over time .