MTADS Geophysical Survey of Potential Underground Storage Tank Sites at the Naval District Washington Anacostia Annex

Abstract : The Naval Research Laboratory performed a georeferenced, digital geophysical survey of eight sites at the Naval District Washington Anacostia Annex to determine the presence of underground storage tanks (USTs). The surveys were conducted using the Multi-sensor Towed Array Detection System (MTADS) using a pulsed-induction sensor array, a total-field magnetometer array, or both arrays on each site. Survey results were analyzed and are presented as anomaly image maps for each of the sites. On three sites we find evidence of UST-like objects near the locations identified by a search of historical records. On two sites we do not find anomalies with the characteristics of USTs. Two additional sites and part of a third are paved and have extensive utilities under the pavement. The underground utilities drive the sensors to near saturation, severely limiting detection sensitivity for deeply buried USTs. Our negative results do not necessarily rule out USTs on these sites. The final site is a mixture of grassy and paved areas. Four potential USTs are identified from historical records as possibly under the grassy area; we find no evidence for them.