Rapid Response Surveys of Mobility, Burial and Re-Exposure of Underwater Munitions in Energetic Surf-Zone Environments and Object Monitoring Technology Development
Abstract
The development of predictive models and measurement techniques for the mobility, burial and re-exposure of munitions is essential to planning remediation efforts. The goal of the this work was to develop technology for rapid response surveys of seafloor morphology, bathymetry, location and state of burial of surrogate UXO and conduct field measurements that span the relevant parameter space at the transition from burial to initial mobility and to migration. To further our understanding of UXO burial and mobility processes, realistic size and density active UXO surrogates were deployed in the surf-zone immediately before extremely energetic wave events. This rapid response mode of deployment surveying aimed to fill gaps in our knowledge in parts of parameter space (very energetic conditions, rapidly changing bathymetry and realistic UXO densities) that have not been adequately sampled by previous field efforts. The location of the UXO and surf-zone bathymetry was surveyed using a recently developed small autonomous surf capable vessel (ASV) with a PPK GPS/Echosounder bathymetry sensor and ultra-short base line (USBL) receiving array for tracking surrogate UXO with active acoustic sources. This study documented that hydrodynamic sand sediment transport convergence associated with sand bar dynamics (e.g. the balance between offshore directed undertow and onshore directed wave skewness and acceleration) can result in little UXO migration even in very energetic surf zone conditions, in contrast to a previous study which had large migration rates in moderate conditions. The parameterized dynamic force balance model was used to successfully hindcast UXO migration using forcing from the SWASH nearshore wave and flow model. These deterministic models have potential to be used as input to statistical models for operation over longer time periods and larger spatial domains with greater uncertainty in forcing conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 28, 2020
- Accession Number
- AD1169183
Entities
People
- Fredric Jaffre
- Peter Traykovski
Organizations
- Woods Hole Oceanographic Institution