In the same ways as our printed publications, digital data released by the DGS represent the results of original professional research and as such are used by professionals and the public.
The Cypress Swamp of Sussex County, Delaware, is underlain by a body of late Pleistocene- to Holocene-age unconsolidated sediments. They form a mappable geologic unit herein named the Cypress Swamp Formation. Deposits of the formation can be found outside the current boundaries of the Cypress Swamp and record the erosion and redistribution of older Pleistocene coastal and Pliocene sedimentary units.
The stream-gaging network in Delaware is a major component of many types of hydrologic investigations. To ensure that the network is adequate for meeting multiple data needs by a variety of users, it must represent the range of hydrologic conditions and land-use types found in Delaware, and include enough stations to account for hydrologic variability. This report describes the current stream-gaging network in Delaware and provides an evaluation of its representativeness for the State.
OFR46 Storm-Water and Base-Flow Sampling and Analysis in the Nanticoke River Watershed: Preliminary Report of Findings 2002-2004
This report provides initial research results of a storm-water and baseflow sampling and analysis project conducted by the University of Delaware, College of Marine and Earth Studies and the Delaware Geological Survey. Baseflow samples were collected from four tributary watersheds of the Nanticoke River and one station on the Nanticoke River on 18 occasions from March 2003 to June 2004. Water samples were filtered in the field to separate dissolved nutrients for subsequent analysis, and separate samples were collected and returned to the laboratory for particulate nutrient determinations. On each sampling
date, temperature, conductivity, pH, and dissolved oxygen concentrations were determined at each sampling station. The U.S. Geological Survey made stream discharge measurements at each of these sites under a joint-funded agreement with the Delaware Department of Natural Resources and Environmental Control and the Delaware Geological Survey. Together, the
nutrient and discharge data were used to determine the total nutrient loads at five stations and unit loads (normalized to watershed area) at two of those stations on a quarterly and annual basis. Problems with watershed delineation and low quality discharge data limit these calculations for some watersheds. At the same five stations, storm water was collected during six storms from March 2003 to June 2004. Storm-water loadings of nutrients in each watershed were calculated from the concentrations of nutrients in water samples collected at fixed time intervals from the beginning of the storm-water discharge period until recession to baseflow. Measured storm loads were used as the basis for estimating loads from unsampled storms.
These data provide the Delaware Department of Natural Resources and Environmental Control with a more complete picture of the seasonal dependence of nutrient loading to streams in the Nanticoke River watershed and to Chesapeake Bay receiving waters. These may also be used to establish total maximum daily load goals.
OFR44 Storm-Water and Base-Flow Sampling and Analysis in the Delaware Inland Bays Preliminary Report of Findings 1998-2000
This report provides initial research results of a storm-water and base-flow sampling and analysis project conducted by the University of Delaware College of Marine Studies (CMS) and the Delaware Geological Survey (DGS). Base-flow samples were collected from six tributary watersheds of Delaware’s Inland Bays on 29 occasions from October 1998 to May 2000. Water samples were filtered in the field to separate dissolved nutrients for subsequent analysis, and a separate sample was collected and returned to the laboratory for particulate nutrient determinations. On each sampling date, temperature, conductivity, pH, and dissolved oxygen concentrations were determined at each sampling station. Stream discharge measurements at each of these sites were made by the U.S. Geological Survey (USGS) under a joint-funded agreement with the Delaware Department of Natural Resources and Environmental Control (DNREC) and the DGS. Together, the nutrient and discharge data were used to determine the total and unit (normalized to watershed area) nutrient loading from base flow to the Inland Bays from each of these watersheds on a quarterly and annual basis. At the same six stations, storm water was collected during eight storms from May 1999 to April 2000. Storm-water loadings of nutrients from each watershed were calculated from the concentrations of nutrients in water samples collected at fixed time intervals from the beginning of the storm-water discharge period until recession to base flow. These data provide DNREC with a more complete picture of the seasonal dependence of nutrient loading to the Bays from which to establish goals for total maximum daily loads in the Inland Bays watershed.
OFR40 Summary Report: The Coastal Storms of January 27-29 and February 4-6, 1998, Delaware and Maryland
In the period between January 27 and February 6, 1998, the Mid-Atlantic region experienced two significant northeasters that affected the coast of Delaware and Maryland. These storms produced heavy rains and high winds, waves, and tides that created dune washovers, flooding, wind damage, and beach erosion and migration. Coastal communities were impacted by flooding that closed roads, by beach erosion that affected structures, streets and boardwalks, and by high winds that damaged structures and trees. This report summarizes the geologic and climatologic nature and effects of these storms and compares them with other similar storms. Post-storm geologic observations from Delaware and Maryland are given in Appendix A.
Data from three streamflow water-quality stations were statistically analyzed to determine the relationships of the major inorganic chemical constituents to specific conductance and to stream discharge. The results show that ion concentrations varied directly with the flow and with specific conductance. A set of regression equations defining these relationships were derived for each of the three stations: Brandywine Creek at Wilmington, St. Jones River at Dover, and Nanticoke River near Bridgeville.
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.
On October 21, 1878, a hurricane crossed the island of Cuba and headed east of Key West, Florida. On the evening of October 22, it made landfall north of Cape Lookout, North Carolina, as a low Category 2 hurricane with winds around 100 mph. The storm picked up speed after landfall and moved northward at a rate of greater than 40 mph and maintained tropical storm force wind speeds of greater than 60 mph with gusts much higher. On the morning of October 23, it passed up the west side of the Chesapeake Bay near the cities of Baltimore and Annapolis, Maryland, Wilmington, Delaware, and Philadelphia, Pennsylvania. By the late afternoon it had reached Albany, New York, and turned eastward and passed out to sea north of Boston, Massachusetts, on the morning of October 24.