This map was constructed primarily to indicate the possibilities for artificial recharge into both the surficial sediments of Quaternary age (exclusive of soils) and the older, immediately underlying sediments. However it can also be used to determine where natural recharge might be entering the ground most readily in those areas relatively free from impermeable cover. The surficial sediments include micaceous sands and gravels in the vicinity of the Fall Line derived from underlying crystalline rocks, Holocene marsh deposits, Delaware River sediments, and the Columbia Formation of Pleistocene age. The Columbia Formation is composed of poorly sorted sands with some gravels, silts and occasional clays. The unit is one of the most important ground-water reservoirs in New Castle County.
Please give proper credit to the Delaware Geological Survey.
Petty, S., Miller, W.D., Lanan, B.A., 1983, Potential for Ground-Water Recharge in the Coastal Plain of Northern New Castle County, Delaware: Delaware Geological Survey Open File Report R2
Delaware Geological Survey
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