A search for aquifers of sand and gravel by electrical-resistivity methods in north-central New Castle County, Delaware

A search for aquifers in an area immediately north of the Chesapeake and Delaware Canal in New Castle, Del., has been made by an electrical resistivity study.  The search located 32 sites that may be underlain by sand and gravel. The thicker deposits are significant with respect to the occurrence of ground water, and all of them are of interest as possible sources of sand and gravel for construction purposes, such as for highway construction.  The thickness of these deposits ranges from 4.4 feet to 77 feet, and the computed resistivity for these ranges from a low of 97,800 ohm-cms to a high of 423,800 ohm-cms.  The study located with certainty one buried channel filled with sand and gravel deposits and pointed out the possibility of others that may be aquifers.  The interpretations show that a large deposit of sand and gravel is present in the eastern part of the area investigated and it is tentatively assumed that this deposit is continuous and may yield large quantities of ground water.  Places where the deposit was found to be the thickest and of high resistivity are described.