ART Engineering LLC  was contracted by SAIC under contract to Navy’s Engineering Field Activity Northeast division to perform an underwater Ground Penetrating Radar (GPR) Survey using its AquaScan survey technology. The Philadelphia Naval Reserve Basin (PNBC) is located approx. 2 miles east of Philadelphia International Airport. The survey was performed in support of a dredging project being conducted by the Navy’s Engineering Field Activity Northeast division. The purpose of the survey was to map subsurface lithologies i.e. distinguish (contaminated) clay/silt from underlying (clean) sand and gravel to fill data needs for dredge design and to determine dredging volumes (e.g., volume of silt /clay sediments associated with contaminants).

For the survey, a submersible radar antenna unit was used which was submerged to 26' below water surface supported from an adjustable steel pole mounted on the side of a midsize survey boat.

An example radar profile with interpretation is provided below.

RESULTS

The radar data were calibrated against core data available from 2004 Vibracore investigation. After calibration, the radar data was converted to depths. Contour maps of top of clay/silt, top of sand and sediment thickness contour maps and 3 D visualizations were generated. The silt/clay sediment volume was calculated using positive and negative cut and fill volumes.

Example Boring Correlation (Green lines indicate survey track lines)

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