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Site content related to keyword: "Sussex County"

B15 Digital Model of the Unconfined Aquifer in Central and Southeastern Delaware

B15 Digital Model of the Unconfined Aquifer in Central and Southeastern Delaware

The unconfined aquifer in central and southeastern Delaware occurs as a southward-thickening blanket of fine to coarse sand, and is recharged almost totally by precipitation and discharge is principally by seepage to streams, bays, and the ocean.

B8 Water Resources of Sussex County, Delaware

B8 Water Resources of Sussex County, Delaware

Sussex County is in the Atlantic Coastal Plain. Its relatively flat, featureless topography is characterized by two terrace-like surfaces; the lower one rises from sea level to about 40 feet above sea level, and the higher one rises inland from 40 to about 60 feet above sea level. Peculiar landforms of low relief, broad ovals, similar to the "Carolina bays," and to the "New Jersey basins" are common on the sandy flat divides in Sussex County. Hydrologically, they are sites of much ground-water discharge, by evapotranspiration, from meadow and marsh of lush vegetation.

Delaware Offshore Geologic Inventory

Delaware Offshore Geologic Inventory Map
Project Contact(s):

Since 1992, the Delaware Geological Survey (DGS) has compiled a geologic database known as the Delaware Offshore Geologic Inventory (DOGI) that consists of sediment samples, radiocarbon and amino acid racemization dates, seismic profiles, and vibracores taken from the nearshore and inner continental shelf in state and federal waters. Most of the 366 vibracores are stored at the DGS on-site core and sample repository.

Coastal Plain Rock Units (Stratigraphic Chart)

The geology of Delaware includes parts of two geologic provinces: the Appalachian Piedmont Province and the Atlantic Coastal Plain Province. The Piedmont occurs in the hilly northernmost part of the state and is composed of crystalline metamorphic and igneous rocks. This chart summarizes the age and distribution of the geologic units that are recognized in the state by the Delaware Geological Survey.

RI23 Cretaceous and Tertiary Section, Deep Test Well, Greenwood, Delaware

RI23 Cretaceous and Tertiary Section, Deep Test Well, Greenwood, Delaware

Analyses of drillers' and geophysical logs, cuttings, and 29 core samples from well Nc13-3 near Greenwood, Sussex County, Delaware indicate that the 1500-foot section penetrated by the drill can be divided into seven rock-stratigraphic units: Matawan Formation, Monmouth Formation, unit A, Piney Point Formation, Chesapeake Group (undifferentiated), Staytonville unit, and the Columbia Formation. The rock units are identified on the basis of texture, mineralogy, color, and interpretation of electric and gamma-ray logs. The oldest rocks penetrated are Upper Cretaceous; Tertiary and Quaternary rocks were also encountered. Correlations of the units encountered in the Greenwood test well with subsurface formations in adjacent parts of the Coastal Plain are explored utilizing lithologies, ages, positions in the stratigraphic column, and geophysical characteristics as criteria. Major time boundaries (Cretaceous-Tertiary; Early-Late Paleocene; Paleocene-Eocene; and Eocene-Miocene) are established by a preliminary study of mainly planktonic foraminifera. The Miocene-Pleistocene boundary was determined on changes in lithology across the unconformable contact.

RI17 Ground-Water Geology of the Delaware Atlantic Seashore

RI17 Ground-Water Geology of the Delaware Atlantic Seashore

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. Recent data from deep wells has enabled the construction of a more accurate geologic framework upon which the hydrologic data are superimposed. Correlation of Miocene sands concludes that the Manokin aquifer lies at greater depths in southeastern Delaware than previously thought.

HM12 Ground-Water Recharge Potential Sussex County, Delaware

HM12 Ground-Water Recharge Potential Sussex County, Delaware

The ground-water recharge potential map of Sussex County, Delaware, is a compilation of 1:24,000-scale maps of the water-transmitting properties of sediments in the interval between land surface and 20 ft below land surface. Water-transmitting properties are a key factor in determining the amount of water that recharges Delaware’s aquifers and the susceptibility of aquifers used as sources of water supply to contamination from near-surface pollutant sources. The mapping methodology was developed by Andres (1991) for the geologic characteristics of the Atlantic Coastal Plain portion of Delaware. Mapping and methods development started in 1990 and the final maps were completed in 2002 (Andres et al., 2002). Additional information about the map and methodology and a list of cited references are presented on the reverse side. The mapping program was funded by the Delaware Department of Natural Resources and Environmental Control and the Delaware Geological Survey.

Map Scale: 
24,000

HM7 Geohydrology of the Southern Coastal Area, Delaware

Geohydrology of the Southern Coastal Area, Delaware

Geology and hydrology of the Southern Coastal Area, Delaware. There are 2 sheets in this series.

Map Scale: 
24,000

GM12 Geology of the Lewes and Cape Henlopen Quadrangles, Delaware

GM12 Geology of the Lewes and Cape Henlopen Quadrangles, Delaware

The surficial geology of the Lewes and Cape Henlopen quadrangles reflects the geologic history of the Delaware Bay estuary and successive high and low stands of sea levels during the Quaternary. The subsurface Beaverdam Formation was deposited as part of a fluvial-estuarine system during the Pliocene, the sediments of which now form the core of the Delmarva Peninsula. Following a period of glacial outwash during the early Pleistocene represented by the Columbia Formation found to the northwest of the map area (Ramsey, 1997), the Delaware River and Estuary developed their current positions. The Lynch Heights and Scotts Corners Formations (Ramsey, 1993, 1997, 2001) represent shoreline and estuarine deposits associated with high stands of sea level during the middle to late Pleistocene on the margins of the Delaware Estuary. In the map area, the Lynch Heights Formation includes relict spit and dune deposits at the ancestral intersection of the Atlantic Coast and Delaware Bay systems, similar in geomorphic position to the modern Cape Henlopen.

Map Scale: 
24,000

GM11 Geology of the Ellendale and Milton Quadrangles, Delaware

GM11 Geology of the Ellendale and Milton Quadrangles, Delaware

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.

Map Scale: 
24,000

GM9 Geology of the Seaford Area, Delaware

GM9 Geology of the Seaford Area, Delaware

This map shows the distribution of geologic units found at or near land surface. These units support agriculture and development, are mined for sand and gravel resources, and are the surface-to-subsurface pathway for water. Previous maps and reports covering the same of adjacent areas have focused on hydrogeology (Andres, 1994), surficial geology on a regional basis (Jordan, 1964, 1974; Owens and Denny, 1979, 1986; Denny et al., 1979; Ramsey and Schenck, 199), or subsurface geology (Hansen, 1981; Andres, 1986).

Map Scale: 
24,000

Digital Watershed and Bay Boundaries for Rehoboth Bay, Indian River Bay, and Indian River (OFR 47)

Digital Watershed and Bay Boundaries for Rehoboth Bay, Indian River Bay, and Indian River (OFR 47)

Digital watershed and bay polygons for use in geographic information systems were created for Rehoboth Bay, Indian River, and Indian River Bay in southeastern Delaware. Polygons were created using a hierarchical classification scheme and a consistent, documented methodology that enables unambiguous calculations of watershed and bay surface areas within a geographic information system. The watershed boundaries were delineated on 1:24,000-scale topographic maps. The resultant polygons represent the entire watersheds for these water bodies, with four hierarchical levels based on surface area. Bay boundaries were delineated by adding attributes to existing polygons representing water and marsh in U.S. Geological Survey Digital Line Graphs of 1:24,000-scale topographic maps and by dissolving the boundaries between polygons with similar attributes. The hierarchy of bays incorporates three different definitions of the coastline: the boundary between open water and land, a simplified version of that boundary, and the upland-lowland boundary. The polygon layers are supplied in a geodatabase format.

DGS Geologic Map No. 9 (Seaford area) Dataset

DGS Geologic Map No. 9 (Seaford area) Dataset

These raster and vector datasets contains the rock unit polygons for DGS Geologic Map No. 9 (Seaford). This map shows the distribution of geologic units found at or near land surface.

RI9 Ground-Water Levels in Delaware January, 1962 - June, 1966

RI9 Ground-Water Levels in Delaware January, 1962 - June, 1966

This report deals with fluctuations in nine observation wells during the period 1960 - 1966. These wells are part of a state-wide ground-water monitoring network and are located in areas of little or no pumping. Eight of the wells respond to water-table conditions; the ninth well appears to reflect artesian conditions.
Although precipitation throughout Delaware was generally below average during the period covered by this report, annual average water levels declined very little in the wells reported on here. There is some evidence, however, for a lowering of water-table levels by three to four feet during the period 1960 - 1962.

RI8 Evaluation of the Water Resources of Delaware

RI8 Evaluation of the Water Resources of Delaware

At present, Delaware has an abundance of water for the foreseeable future, but is already faced with water problems in some municipalities. These can only be resolved satisfactorily through complete evaluation of the State's water resources and the establishment of a coordinated program of water management.