Investigation of the Use of Geobags to Immobilize Submerged Munitions: A Report on the Concept, Development, and Testing

Abstract : Underwater munitions pose a risk to human health and safety as well as a potential threat to the environment. Current management options are limited to removal, in-place detonation, or leave-in-place. Furthermore, munitions subjected to ocean currents may be mobile, confounding monitoring, removal or detonation after initial detection. Capping technology used in the control of contaminated sediments has the potential to immobilize and isolate munitions from the overlying water column thereby safeguarding human exposure and the environment. This study designed, developed, and tested geobags for immobilizing submerged munitions. Geobags are constructed from synthetic geotextiles and filled with sand. Typical sizes of geobags used were 5 ft x 2.5 ft with filled weights varying between 500 and 1200 pounds. Tests were conducted in still and flowing waters to demonstrate whether geobags were a viable option for dealing with underwater munitions. Results indicate geobags, when properly placed, would immobilize a munition and completely surround it thereby isolating it from the overlying water column. This cap would prevent any spills or releases from the munition from entering the environment and also safeguarding human exposure. With an estimated design life exceeding 100 years, geobags provide an inexpensive, easy to implement method to address the issue of submerged munitions.