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Site content related to keyword: "coastal geology"

RI55 Geology of the Milford and Mispillion River Quadrangles

RI55 Geology of the Milford and Mispillion River Quadrangles

Investigation of the Neogene and Quaternary geology of the Milford and Mispillion River quadrangles has identified six formations: the Calvert, Choptank, and St. Marys formations of the Chesapeake Group, the Columbia Formation, and the Lynch Heights and Scotts Comers formations of the Delaware Bay Group. Stream, swamp, marsh, shoreline, and estuarine and bay deposits of Holocene age are also recognized. The Calvert, Choptank, and St. Marys formations were deposited in inner shelf marine environments during the early to late Miocene. The Columbia Formation is of fluvial origin and was deposited during the middle Pleistocene prior to the erosion and deposition associated with the formation of the Lynch Heights Formation. The Lynch Heights Formation is of fluvial and estuarine origin and is of middle Pleistocene age. The Scotts Corners Formation was deposited in tidal, nearshore, and estuarine environments and is of late Pleistocene age. The Scotts Corners Formation and the Lynch Heights Formation are each interpreted to have been deposited during more than one cycle of sea-level rise and fall. Latest Pleistocene and Holocene deposition has occurred over the last 11,000 years.

RI54 Radiocarbon Dates from Delaware: A Compilation

RI54 Radiocarbon Dates from Delaware: A Compilation

Radiocarbon dates from 231 geologic samples from the offshore, coastal, and upland regions of Delaware have been compiled along with their corresponding locations and other supporting data. These data now form the Delaware Geological Survey Radiocarbon Database.

RI73 Analysis and Summary of Water-Table Maps for the Delaware Coastal Plain

RI73  Analysis and Summary of Water-Table Maps for the Delaware Coastal Plain

A multiple linear regression method was used to estimate water-table elevations under dry, normal, and wet conditions for the Coastal Plain of Delaware. The variables used in the regression are elevation of an initial water table and depth to the initial water table from land surface. The initial water table is computed from a local polynomial regression of elevations of surface-water features. Correlation coefficients from the multiple linear regression estimation account for more than 90 percent of the variability observed in ground-water level data. The estimated water table is presented in raster format as GIS-ready grids with 30-m horizontal (~98 ft) and 0.305-m (1 ft) vertical resolutions. Water-table elevation and depth are key facets in many engineering, hydrogeologic, and environmental management and regulatory decisions. Depth to water is an important factor in risk assessments, site assessments, evaluation of permit compliance data, registration of pesticides, and determining acceptable pesticide application rates. Water-table elevations are used to compute ground-water flow directions and, along with information about aquifer properties (e.g., hydraulic conductivity and porosity), are used to compute ground-water flow velocities. Therefore, obtaining an accurate representation of the water table is also crucial to the success of many hydrologic modeling efforts. Water-table elevations can also be estimated from simple linear regression on elevations of either land surface or initial water table. The goodness-of-fits of elevations estimated from these surfaces are similar to that of multiple linear regression. Visual analysis of the distributions of the differences between observed and estimated water elevations (residuals) shows that the multiple linear regression-derived surfaces better fit observations than do surfaces estimated by simple linear regression.

SP10 Selected Papers on the Geology of Delaware

SP10 Selected Papers on the Geology of Delaware

The Delaware Academy of Science has been instrumental in informing Delaware citizens about science and utilization of local resources. Since 1970 the annual meeting of the Delaware Academy of Science has been used as a time for presentation of ongoing research in various areas of science in the Delaware region. The proceedings of these meetings have resulted in publication of transactions of the Delaware Academy of Science. The 1976 annual meeting focused on aspects of the geology of Delaware. Members of the Delaware Geological Survey and the Geology Department at the University of Delaware contributed papers in their specific disciplines. This volume presents an overview of studies of geological features and processes of evolution of the geology of Delaware. Although this collection of papers does not represent an all-inclusive study of the subject, the selections included in this volume highlight past, present, and future trends in the study of Delaware's geology. It is hoped that the combined bibliographies of all the papers will provide a comprehensive view of the literature for further investigation into the geology of Delaware.

OFR41 Beach Sand Textures from the Atlantic Coast of Delaware

OFR41 Beach Sand Textures from the Atlantic Coast of Delaware

The purpose of this report is to characterize Delaware Atlantic Coast beach sand on the basis of sand texture data in order to identify geologic material suitable for beach nourishment.

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OFR37 Summary Report: The Coastal Storm of December 10-14, 1992, Delaware and Maryland

OFR37 Summary Report: The Coastal Storm of December 10-14, 1992, Delaware and Maryland

On December 10, a low pressure system moved rapidly north-northwest from eastern North Carolina and Virginia, up the Chesapeake Bay to a position just west of Chestertown in Kent County, Maryland by 0700 on December 11. The system then moved irregularly to the southeast, stalled for several hours over Georgetown, Delaware, and proceeded offshore early on December 12. Approximate locations of the storm's track are shown on Figure 1. The storm had associated rain that contributed to some local stream flooding and high winds that created strong surf and waves. The waves were compounded by an astronomical high tide (full moon) to produce coastal flooding along Delaware Bay and some breaching of the dunes along the Atlantic coast. The position of the storm offshore blew north-northeast winds onto the coast and abnormally high tides continued through December 15.

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OFR36 Summary Report: The Storm of January 4, 1992

OFR36 Summary Report: The Storm of January 4, 1992

On January 4, 1992 an intense storm moved from the east across the Delmarva Peninsula and the Chesapeake Bay. Its track was the result of the low pressure being pulled westward by a strong cold-cored upper low moving across Georgia and South Carolina. The storm exhibited tropical/subtropical characteristics on radar. Satellite photos indicate that an "eye" to the storm formed just prior to landfall. Landfall occurred over the southern Delmarva Peninsula just prior to the time of high tide (0648 at Ocean City, Md). The storm weakened rapidly as it moved over land areas with a secondary area redeveloping farther out to sea later in the day on the 4th. Approximate locations of the storm's track are given on Figure 1. As the storm moved across the Delmarva Peninsula perpendicular to the coast, Delaware was in the right-foreward quadrant to the north of the "eye" of the storm. This position typically produces the highest winds associated with a tropical storm. These winds created high waves that in conjunction with an astronomical high tide (new moon) produced strong surf and abnormally high tides along the shore. Rainfall from the storm in Delaware was not heavy enough to cause flooding of streams. Coastal flooding of marshes and low-lying areas did occur along the Inland Bays and along Delaware Bay.

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SP26 Historical Coastline Changes of Cape Henlopen, Delaware

SP26 Historical Coastline Changes of Cape Henlopen, Delaware

Coastlines are not static features. They are shaped by the daily effects of wind, current, and wave activity. Over time, a coastline may move landward due to relative sea-level rise or low sediment supply, or seaward due to relative sea-level fall or an overabundance of sediment. Perhaps the most striking example of shoreline movement in Delaware is at Cape Henlopen which has grown northward approximately one mile in the last 160 years. Maps and aerial photographs show these changes.

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.

Geologic History of the Delaware Coastal Plain

In Delaware, the oldest unit of the Atlantic Coastal Plain is the Potomac Formation. Sediment eroded from the Appalachian Mountains was deposited in rivers and swamps in a tropical climate along the margins of the forming ocean during the latter part of Early Cretaceous time, about 120 million years ago.

The Geology of Delaware

The Geology of Delaware is an online resource for information about the geology and hydrogeology of Delaware. Information on these pages is explained in general terms although common geologic terminology is used. This book covers the major important factors in Delaware geology as well as latest research. Additional information is provided at the bottom of some pages and on the last page of the book, More Information.

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.

EPSCoR seed grants awarded to environmental researchers

Tom McKenna measuring subsurface temperature along the shoreline of Indian River in Sussex County, Delaware. Photo by Doug Miller

With a focus on environmental issues important to the state, the Delaware National Science Foundation Experimental Program to Stimulate Competitive Research (NSF EPSCoR) office has awarded five seed grants to investigators whose projects aim to solve environmental problems in Delaware.

DGS Publications

The core of much DGS work culminates in the release of data and findings in official DGS publications, including Open File Reports, Reports of Investigations, Geologic Maps, Hydrologic Maps, and Bulletins.

DGS issues report on the geology of Bethany Beach

RI75 Stratigraphy And Correlation Of The Oligocene To Pleistocene Section At Bethany Beach, Delaware

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.