Monitoring Dredged Material Disposal at Mouth of Columbia River, Washington/Oregon, USA
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICSLAB
Pagination or Media Count:
The entrance channel at the Mouth of the Columbia River requires annual dredging of 3 to 5 million cu m 3.9 to 6.5 million cu yd of fine-to-medium sand to maintain the navigation channel at the authorized depth. The sandy dredged material is placed in EPA- approved Ocean Dredged Material Disposal Sites ODMDS. Exceedance of ODMDS capacity at the Mouth of the Columbia River creates two, operational problems for the Portland District a The overall footprint of disposed dredged material extends beyond the existing ODMDS formally permitted boundaries by as much as 915 m 3,000 ft in some cases, and b dredged material within the ODMDS has accumulated to such an aerial and vertical extent that adverse sea conditions are created. In some cases, mounds rise 18.3 to 21.4 m 60 to 70 ft above surrounding bathymetry. Mariners report that the ODMDS mounds cause waves to steepen andor break in the vicinity of the sites, and that these waves conditions are hazardous to navigation.
- Hydrology, Limnology and Potamology
- Solid Wastes and Pollution and Control