Deepening of the San Diego Harbor & Study to Remove UXO from Large Quantities of Dredge Spoils

In 1997 and 1998, over 5.4 million cubic meters (cm) of material were dredged to deepen the San Diego Harbor to accommodate NIMITZ class aircraft carriers at Naval Air Station North Island. This was the largest dredging project undertaken in San Diego Harbor since 1975 when the Army Corps of Engineers dredged the back channel to –35.0 ft MLLW. The project was completed in 1998 by a joint venture of Great Lakes and Stuyvesant Dredging Company at a total cost of $40 Million. Siting studies, sediment transport analysis and environmental assessments of 16 nearshore and on-shore beach sites in San Diego County were carried out and a total of nine beach sites were permitted for beneficial use of the predominantly sandy materials. The project was complicated when munitions (unexploded ordnance or UXO) were discovered in spoils being pumped to the on-shore beach sites. This necessitated a study of all available technologies to remove munitions from over 3 million cm of material planned for beach nourishment. Ultimately, it was determined that, due to the project schedule, environmental regulations, funding constraints and large quantities of dredge spoils, it was not feasible to economically screen the munitions. An alternative approach was developed to complete the dredging and provide for beach nourishment.