Seismic Refraction And Electromagnetic Methods For Mapping Confining Layer In Central New Jersey

The Woodbury clay is one of the major hydrogeologic confining<br>units in the New Jersey coastal plain. It separates two main<br>aquifer systems; the Englishtown and the Potomac-Raritan-Magothy<br>aquifers. Therefore, at a hazardous waste site, it is important<br>to map the surface of this confining layer to help define the<br>local hydrostratigraphy, ground water flow and possible contaminant<br>transport.<br>In a contaminated site in central New Jersey two wells were<br>drilled to determine the vertical extension of a contaminant and<br>the direction of groundwater flow. The drilling results show a<br>difference in the depth of the Woodbury clay between the two<br>wells and some thin clay beds. At this stage geophysical support<br>was requested to map the Woodbury clay between the two wells and<br>to determine the depth to the water table.