Share

First State Geology Newsletter Signup

First State Geology has been the newsletter of DGS for over 25 years.

Click here to signup!

Site content related to keyword: "hydrogeology"

Well and Water Level Summary for Wells with 4 or More Observations

Well and Water Level Summary for Wells with 4 or More Observations - Well Cb15-04

Groundwater levels are basic information needed for evaluating water conditions and for basic and applied research. For these efforts, water levels are being measured statewide in wells completed in multiple aquifers. Some wells are measured for specific projects, such as the Coastal Aquifers Salinity Project and the Water Conditions program, while other wells are measured so that staff can maintain long-term records of groundwater levels for evaluation of trends.

Table contains summary data from wells having 4 or more water level observations.

This page tagged with:

DGS releases report on subsurface geology of Delaware City area

The Delaware Geological Survey (DGS) has published a report that details new findings on the subsurface geology of the Delaware City area.

Titled Subsurface Geology of the area between Wrangle Hill and Delaware City, Delaware, Report of Investigations Number 78 presents the results of cooperative research between geological consultant John W. Jengo of the firm MWH Americas and DGS researchers Peter P. McLaughlin Jr. and Kelvin W. Ramsey.

RI78 Subsurface Geology of the Area Between Wrangle Hill and Delaware City, Delaware

RI78 Subsurface Geology of the Area Between Wrangle Hill and Delaware City, Delaware

The geology and hydrology of the area between Wrangle Hill and Delaware City, Delaware, have been the focus of numerous studies since the 1950s because of the importance of the local groundwater supply and the potential environmental impact of industrial activity. In this report, 490 boreholes from six decades of drilling provide dense coverage, allowing detailed characterization of the subsurface geologic framework that controls groundwater occurrence and flow.

The region contains a lower section of tabular Cretaceous strata (Potomac, Merchantville, Englishtown, Marshalltown,and Mount Laurel Formations in ascending order) and a more stratigraphically complex upper section of Pleistocene-to-modern units (Columbia, Lynch Heights, and Scotts Corners Formations, latest Pleistocene and Holocene surficial sediments and estuarine deposits). The lowermost Potomac Formation is a mosaic of alluvial facies and includes fluvial channel sands that function as confined aquifer beds; however, the distribution of aquifer-quality sand within the formation is extremely heterogeneous. The Merchantville Formation serves as the most significant confining layer. The Columbia Formation is predominantly sand and functions as an unconfined aquifer over much of the study area.

To delineate the distribution and character of the subsurface formations, densely spaced structural-stratigraphic cross sections were constructed and structural contour maps were created for the top of the Potomac Formation and base of the Columbia Formation. The Cretaceous formations form a series of relatively parallel strata that dip gently (0.4 degrees) to the southeast. These formations are progressively truncated to the north by more flatly dipping Quaternary sediments, except in a narrow north-south oriented belt on the east side of the study area where the deeply incised Reybold paleochannel eroded into the Potomac Formation.

The Reybold paleochannel is one of the most significant geological features in the study area. It is a relatively narrow sandfilled trough defined by deep incision at the base of the Columbia Formation. It reaches depths of more than 110 ft below sea level with a width as narrow as 1,500 ft. It is interpreted to be the result of scour by the sudden release of powerful floodwaters from the north associated with one or more Pleistocene deglaciations. Where the Reybold paleochannel cuts through the Merchantville confining layer, a potential pathway exists for hydrological communication between Columbia and Potomac aquifer sands.

East of the paleochannel, multiple cut-and-fill units within the Pleistocene to Holocene section create a complex geologic framework. The Lynch Heights and Scotts Corners Formations were deposited along the paleo-Delaware River in the late Pleistocene and are commonly eroded into the older Pleistocene Columbia Formation. They are associated with scarps and terraces that represent several generations of sea-level-driven Pleistocene cut-and-fill. They, in turn, have been locally eroded and covered by Holocene marsh and swamp deposits. The Lynch Heights and Scotts Corners Formations include sands that are unconfined aquifers but complicated geometries and short-distance facies changes make their configuration more complex than that of the Columbia Formation.

Delaware Geologic Information Resource (DGIR) Map Viewer

DGIR Map Viewer Screenshot
Project Contact(s):

The Delaware Geologic Information Resource (DGIR) is an online data display tool and map viewer for a variety of geologic and hydrologic information released by the Delaware Geological Survey. It was designed to deliver the most commonly available and requested geologic and hydrologic information that is appropriate for use in hydrologic studies, required by regulation and ordinance, and to support state resource management decisions.

Effect of tropical storms Irene and Lee on groundwater levels in well Qb35-08 near Laurel, Delaware

Rapid, significant groundwater recharge occurred in response to tropical storms Irene and Lee.a

Effect of tropical storms Irene and Lee on groundwater levels in well Qb35-08

Plot of groundwater levels, groundwater temperature, and rainfall near Laurel, Delaware

Tropical storms Irene and Lee caused a 9-1/2 foot rise of the water table in western Sussex County near Laurel. Groundwater levels and temperatures in Qb35-08 were collected with an automated pressure-temperature datalogger system. At the same time, rainfall and soil moisture data were recorded by the DEOS Laurel Airport station located approximately 5 miles from the well.

David R. Wunsch appointed DGS Director

David R. Wunsch appointed DGS Director
Date: Nov 2011

After a nationwide search, David R. Wunsch has been appointed the next Director of the Delaware Geological Survey (DGS) and Delaware State Geologist, effective Nov. 1. He will succeed John H. Talley, who retired on June 30 after more than 38 years of service. Wunsch holds a doctorate in hydrogeology from the University of Kentucky, a master’s degree in geology from the University of Akron, and a bachelor’s degree in geology, with a minor in chemistry, from the State University of New York, Oneonta. In 2011, Wunsch was elected a Fellow of the Geological Society of America. He is an Honorary Member and a past President of the Association of American State Geologists (AASG) and has previously served a term as Secretary of the American Geological Institute.

Wunsch to take helm at DGS

David R. Wunsch, Ph.D.

David R. Wunsch has been appointed the next Director of the Delaware Geological Survey (DGS) and Delaware State Geologist, effective Nov. 1.

Source Water Assessment and Protection Program

Two Delaware Geological Survey staff members attended the Source Water Assessment and Protection Program meeting held Sept. 14 in Dover, Del. Scott Andres made a presentation titled "Results of Field and Lab Experiments on High Rate Land Application of Wastewater" and John Callahan made a presentation titled "Web-Delivered Application for Hydrogeologic Data."

This page tagged with:

DGS honors retiring director, state geologist Talley

Talley is retiring after 38 years of service

John Talley joined the Delaware Geological Survey as a project geologist in 1972, became a senior scientist and hydrogeologist by 1986, and rose to director and state geologist by 2004. He’s consulted with dozens of university, state, and federal governments and groups and amassed a list of more than 50 publications and reports.

The Delaware Water Conditions Summary

The Water Conditions Summary is an online monthly summary of water conditions in Delaware. Principal factors in determining water conditions are precipitation, streamflow, and groundwater levels in aquifers. Data from rain gages, stream gages, and observation wells located throughout Delaware have been collected and compiled since the 1960s by the Delaware Geological Survey. These data are displayed as hydrographs and are also available for download. In general, water is abundant in Delaware, but supply is restricted by natural geologic conditions in some areas, by contamination in others, and is dependent on precipitation.

IS7 The Delaware Geological Survey

IS7 The Delaware Geological Survey

IS7 is a foldout brochure that briefly discusses the background and current activities of the DGS. Specifically, the following major programs are listed: Geology, Hydrology, Cartographic Information, Geologic Hazards, Seismograph Network, Outer Continental Shelf, Mineral Resources, Well Records and Sample Library, Publications, and Joint-funded Programs.

Temporal Imaging of the Intertidal Critical Zone

Time series of thermal images showing increasing temperature (yellow, orange, and red) as warm tidal water flows over a saltmarsh near Bowers Beach, Delaware during a summer evening (June 2009).
Project Contact(s):

We are developing an innovative ground-based imaging system to collect multi-spectral imagery (visible, near and thermal infrared bands) at time-scales (minutes/hours) below those of the dominant processes in intertidal environments (semi-diurnal tides, day/night). A modular system based on mature imaging technology is being assembled for science missions by foot, boat, truck, tower, and lift. This project consists of some critical laboratory studies to test our conceptual framework.

Scientists study flow of groundwater into bays - results may help track pollution

Scientists study flow of groundwater into bays. Results may help track pollution.

On a small, homemade barge, built from the skeleton of an old ship, a gray slurry of bay bottom sand flows out of a pipe into a bucket. Two scientists, a well driller and two student interns drill a hole in the floor of the Indian River Bay. They’ll install a very long pipe into the hole and use it to monitor groundwater – how much flows into the bay, how salty it is and how many nutrients it carries with it.

Web-Delivered Application for Hydrogeologic Data

Project Contact(s):

This project is designed to deliver, by web-based technologies, the most commonly available and requested geologic and hydrologic information used in hydrologic studies required by regulation and ordinance and used by state agencies to support resource-management decisions. Available information can be associated with points or areas. Information associated with points includes descriptive logs, geophysical logs, raw and interpreted groundwater levels, aquifer and geologic unit identification, and hydraulic characteristics of wells. Information associated with areas is either in the form of raster-based (grid) data or polygons. Examples of raster-based data include water-table depths and elevations, tops and thicknesses of geologic and aquifer units, and aquifer transmissivity. Examples of polygons include surficial geology and groundwater recharge potential.

The intent of developing a web-technology enabled system is to provide a more intuitive and comprehensive toolset for locating, quickly viewing, and downloading the desired information in an efficient, extensible, and familiar manner.

Quantifying Geologic and Temporal Controls on Water and Chemical Exchange between Groundwater and Surface Water in Coastal Estuarine Systems

Conceptual models for submarine groundwater discharge
Project Contact(s):

Eutrophication is one of the most common and most severe problems facing coastal bays in
populated and agricultural areas. Unnaturally high quantities of nutrients enter fresh groundwater and surface water as a result of human activities. These nutrients contribute to the overpopulation of phytoplankton and macroalgae in coastal surface waters, which results in deterioration of water quality and animal habitat. This is a particular problem in the Delmarva region, where poultry farms, agricultural activity, and growing human populations have contributed to rapidly declining populations of blue crabs, striped bass, and many other species which live and breed in estuarine waters. The economic value of these species has, in part, prompted political action and efforts to manage nutrient inputs to groundwater and surface water, the primary pathways for nutrient loading to coastal waters. Despite significant reductions, coastal water quality has largely remained poor. A better understanding of the processes that moderate nutrient loading to coastal waters, particularly via groundwater, which is much more difficult to monitor than surface water inputs, is essential for improved management methods that will result in healthy coastal ecosystems. This project will improve understanding of where nutrients are coming from and how loading may be reduced, and may aid in identification of activities that exacerbate negative impacts.

Presentation on groundwater availability

John Talley, of the Delaware Geological Survey, made a presentation titled “Groundwater Availability, Trends in Water Use, and Potential Conflicts” at the Pickle Packers International spring meeting, Philadelphia, April 15.

This page tagged with:

Presentation on assessing suitability of land for rapid infiltration basin systems

Scott Andres and Edward Walther, of the Delaware Geological Survey, presented "Development and Application of a GIS Screening Tool for Assessing Suitability of Land for Rapid Infiltration Basin Systems" at the National Ground Water Association Summit, Denver, April 12-15. Andres also participated in a panel discussion co-sponsored by the U.S. Subcommittee on Groundwater, "National Groundwater Monitoring Network: Listening Session."

This page tagged with:

DGS Cooperative and Joint-Funded Programs

The DGS is, by statute, the state agency responsible for entering into agreements with its counterpart federal agencies, including the U.S. Geological Survey, the USGS Office of Minerals Information (formerly the U.S. Bureau of Mines), and the Bureau of Ocean Energy Management, Regulation and Enforcement (formerly the U. S. Minerals Management Service), and for administering all cooperative programs of the State with these agencies. The DGS also works with many in-state and out-of-state partner agencies and organizations.