The following table displays the correlation of hydrologic units to geologic units recognized by the Delaware Geological Survey in the Atlantic Coastal Plain.
The Bethany Beach borehole (Qj32-27) provides a nearly continuous record of the Oligocene to Pleistocene formations of eastern Sussex County, Delaware. This 1470-ft-deep, continuously cored hole penetrated Oligocene, Miocene, and Pleistocene stratigraphic units that contain important water-bearing intervals. The resulting detailed data on lithology, ages, and environments make this site an important reference section for the subsurface geology of the region.
This project is an integrated geologic/hydrologic study that will update our knowledge of the unconfined aquifers, confined aquifers, and groundwater resources of Sussex County. In addition, this project will utilize the results of recently completed study of the aquifer geology of Kent County (McLaughlin and Velez, 2005) to better define the groundwater resources of Kent County. The products to be produced by this study include aquifer depth and thickness maps and geologic cross sections for Sussex County. Products will also include a summary of basic hydrologic characteristics of aquifers in Kent and Sussex County and an analysis of water use for each aquifer.
Population and accompanying water use are expected to increase by 34 percent in southeastern Delaware between 1975 and 2000. To assess the capability of the aquifers in that area to supply the required amount of ground water, a study of those aquifers was started in 1976. Interpretation of geologic sections developed from drilling and geophysical data showed that the confining beds between the Manokin, Ocean City, and Pocomoke aquifers of Neogene age are thin and discontinuous in some parts of the area.
Southern New Castle County has a land area of 190 square miles in north-central Delaware. It is predominantly a rural area with a population of about 9,000 people who are engaged chiefly in agriculture. By and large, the residents are dependent upon ground water as a source of potable water. This investigation was made to provide knowledge of the availability and quality of the ground-water supply to aid future development. The climate, surface features, and geology of the area are favorable for the occurrence of ground water.
Northern Delaware, the area above the Chesapeake and Delaware Canal in New Castle County, is an area of rapidly growing population and expanding industry. In some places the demand for water has reached or exceeded the capacity of the existing facilities creating apparent water shortages. Many agencies, both public and private, are attempting to alleviate these shortages; studies are being made and reports prepared for immediate action as well as long-term planning. It is the purpose of this report to examine on a long-range basis the water resources of the northern Delaware area.
The need for locating additional sources of ground water for the Delaware Atlantic seashore, a predominantly recreation-oriented area, is indicated by an expanding population in the belt between Philadelphia, Pennsylvania and Washington, D.C., combined with increasing leisure time. Present water use in the shore area is approximately 4 million gallons per day and will reach 9.3 million gallons per day by the year 2000. A new geologic interpretation of the occurrence of deep aquifers in the Delaware Atlantic seashore area is presented.
The surficial geology of the Ellendale and Milton quadrangles reflects the geologic history of the Delaware Bay estuary and successive high and low sea levels during the Quaternary. Ramsey (1992) interpreted the Beaverdam Formation as deposits of a fluvial-estuarine system during the Pliocene. Sediment supply was high, in part due to geomorphic adjustments in the Appalachians related to the first major Northern Hemisphere glaciations around 2.4 million years ago. The Beaverdam Formation forms the core of the central Delmarva Peninsula around which wrap the Quaternary deposits.
The Delaware Geological Survey (DGS) at the University of Delaware released a report that provides new insights into the underground geology and hydrology of southeastern Sussex County, Delaware. The report, "Stratigraphy and Correlation of the Oligocene to Pleistocene Section at Bethany Beach, Delaware," summarizes the results of geological investigations conducted on a 1,470-foot-deep research borehole drilled at Bethany Beach, Del.