Decrease in Harbor Maintenance Dredging through the Use of Pile Dikes and Related Structures Together with an Analysis of Estuarine Sedimentation Problems
Final rept. 1 Jul 1975-30 Jun 1976
NAVAL ACADEMY ANNAPOLIS MD ENERGY-ENVIRONMENT STUDY GROUP
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Most harbors in the continental United States of interest to the U.S. Navy are located within estuaries. Because of the presence of fresh water as well as salt water, special sedimentation problems are created. Eight sources of sediments in an estuary are discussed. Most estuaries are the repository for fine-grained sediments ranging from clay to fine sand in size which would eventually fill the estuary. This report discusses a system to remove sediments by means other than dredging. Part of the system is to entrap estuarine sediment by means of pile dikes to prevent it from entering dredged shipping channels. The pile dike, which consists of two to seven rows of clusters of concrete piles extend perpendicularly to the river bank. The rows are spaced approximately 5 feet apart the clusters 15 feet to 20 feet apart. Stringers are placed between each row and secured to pile clusters and piles are driven about 20 feet to 30 feet below the bottom of the estuary. The second part is to remove periodically the accumulated sedimentary material by a back-flushing and slurry pumping system. The slurry may be pumped to barges, used as landfill, or pumped to off- shore spoil disposal areas such as submarine canyons.
- Civil Engineering
- Structural Engineering and Building Technology