Water Jets Fight Silt

by A. James Bailard, Principal; Bailard Jenkins Technologies, 1150 Bailard Ave., Carpinteria, CA 93013,
A. Rooney Heinz, General Manager; Armwavers Ltd., East Terminal Way, Aberdeen, WA,
A. Scott Jenkins, Professor; Scripps Institution of Oceanography, La Jolla, CA 92093,

Serial Information: Civil Engineering—ASCE, 1989, Vol. 59, Issue 1, Pg. 54-57

Document Type: Feature article


In the largest U.S. application to date, an array of hydraulic jets is being used to scour a ship berth at the Port of Grays Harbor on the coast of Washington. The system has been in place since May 1987 and has virtually eliminated dredging costs for the Port at one berth. It is being extended to a second berth. The Port had been paying as much as $750,000 a year for dredging and still losing business because berths were too shallow and ships could not take on full loads. Commissioners sought new means of maintenance. The jet array system had been developed by two researchers at Scripps Oceanographic Institute in California, and was in the test stage. The Port asked the two to do a feasibility study and, based on that, proceeded with a full-scale jet array system. The system resuspends newly deposited sediments so they can be transported by the ambient currents. At Grays Harbor, they are tidal current, but the system can work with river flows or artificial flows such as sluicing systems. High velocity jets discharge horizontally and promote floc mixing and bottom friction. No element of the system takes up wharf space or projects into the berth. All components are fully automated and accessible for maintenance. A catwalk was hung from the wharf deck and the pile caps that encloses all components in a protected corridor.

Subject Headings: Berths | Tides | Jets (fluid) | Silt | Soil water | Ships | Dredging | Maintenance | Washington | United States

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