It is anticipated that the Department of Defense may need to consider blow-in-place (BIP) options to support the Munitions Response Plan in the underwater environment by 2009. There is also a need to provide this type of mitigation technology to the explosive ordnance disposal (EOD) community to facilitate realistic training scenarios. Underwater BIP operations in support of cleanup projects and training have the potential to damage adjacent natural structure and habitat as well as to adversely impact species such as fish, sea turtles, and marine mammals. The objective of this project is to demonstrate and validate engineering-based methods to mitigate the adverse environmental effects of BIP operations by reducing underwater blast pressure and acoustic energy.

Blast attenuation barrier and mitigation technology in practice for underwater construction/demolition applications is currently directed at bubble curtains, which represent the most mature underwater BIP mitigation attenuation-barrier technology for field demonstration. The effectiveness of bubble curtains at reducing blast pressure, acoustic energy, and environmental impacts will be documented in this project. Other critical issues such as personnel safety, reusability, portability, field fabrication, and total cost (including labor, placement, and equipment) also will be considered. A mitigation technology for three different ordnance items will be demonstrated at an appropriate depth. It is anticipated that use against larger explosive weight unexploded ordnance (UXO) may require a sacrificial blast mitigation system.

There are known regulatory issues associated with acoustic noise and blast effects when introduced into the marine environment. Primary benefits of this effort would include enhanced EOD technician safety, reduced environmental risk, and associated cost avoidance by decreasing shock pressures and noise associated with underwater explosions. Additional benefits would extend to expedited regulatory approval of BIP operations, reduction of Marine Mammal Protection Act defined takes of marine species, and lower mitigation costs. The use of blast mitigation technology also will help meet environmental compliance requirements, enabling ranges to continue operating in support of fleet training opportunity and readiness. (Anticipated Project Completion - 2010)