Identification and Removal of Unexploded Ordnance at a WWII Bombing Range in an Area Undergoing Rapid Development

摘要

The Conway Bombing and Gunnery Range was used by the US Army from 1942 to 1947 to allow pilots to practice bombing, strafing and rocket firing. The former range is located between Conway, South Carolina and Myrtle Beach, South Carolina, in an area that is undergoing rapid commercial and residential development. The range was initially investigated by the US Army Corps of Engineers (COE) in the late 1990s. Their initial investigations included review of historical information about the facility and gathering geophysical information over a very small percentage of the total range. Area III of the range is two miles in diameter (2010 acres) and was used for a wide variety of armaments but mostly 4-pound incendiary bombs, 2.25-inch rockets and 100- pound practice bombs. The vast majority of these weapons did not carry a full charge but rather a smoke charge, which contained a small amount of black powder allowing the pilot to see the weapon strike. Kestrel is managing an investigation and removal action on a parcel containing 325 acres, of which 250 acres are 'upland' and 75 acres are considered jurisdictional wetlands. The Geometrics G-858 magnetometer and the Geonics EM-61 time-domain metal detectors were used to identify subsurface anomalies during the geophysical prove out. The G-858 was superior in routinely identifying UXO like objects to a depth of six feet below ground surface. In addition to meeting the requirements in the COEs Engineering Evaluation and Cost Analysis (EE/CA) report the property imposed an additional requirement of identifying UXO to a depth six feet. In a five acre test area, both instruments were used in combination to determine if the potential to reduce the number of false positives existed. False positives are particularly troublesome because each one requires further investigation costing time and money resulting in no OE/UXO being removed. The cost of managing false positives can be a significant portion of the removal phase of the project and thus reducing the number has the potential to yield cost savings.