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Site content related to keyword: "Rancocas aquifer"

Data and Graphs of Water Level Summaries for Wells with 20+ Years or 100+ Observations

Example Hydrograph for DB24-18 - Water Level Summaries for Wells with 20+ Years or 100+ Observations

Ground-water 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 ground-water levels for evaluation of trends. Table contains summary data from wells having 100 or more water level observations.

Delaware Geologic Information Resource (DGIR) Map Viewer

DGIR Map Viewer Screenshot
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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.

Delaware Groundwater Monitoring Network

The Delaware Geological Survey (DGS) currently monitors groundwater levels in a network of 68 wells in Delaware. Long time-series of water levels in major aquifers serve as critical baseline data for resource management and analyses of aquifer response to pumping, climatic variability, drought hazards, seawater intrusion, and interaction with streams and their ecosystems.

DGS issues report on groundwater modeling in southern New Castle County

The Delaware Geological Survey (DGS) released a new technical report entitled Simulation of Groundwater Flow in Southern New Castle County, Delaware, which was prepared by Changming He and A. Scott Andres of the DGS.

DGS Report of Investigations No. 77 is a preliminary step in developing a detailed understanding of the subsurface hydrology and evaluating groundwater availability in major aquifer systems beneath southern New Castle County and parts of northern Kent County, which are expected to have greater demands for groundwater in the next 20 years due to population growth.

RI77 Simulation of Groundwater Flow in Southern New Castle County, Delaware

RI77 Simulation of Groundwater Flow in Southern New Castle County, DelawareRI77 Simulation of Groundwater Flow in Southern New Castle County, Delaware

To understand the effects of projected increased demands on groundwater for water supply, a finite-difference, steady-state, groundwater flow model was used to simulate groundwater flow in the Coastal Plain sediments of southern New Castle County, Delaware. The model simulated flow in the Columbia (water table), Rancocas, Mt. Laurel, combined Magothy/Potomac A, Potomac B, and Potomac C aquifers, and intervening confining beds. Although the model domain extended north of the Chesapeake and Delaware Canal, south into northern Kent County, east into New Jersey, and west into Maryland, the model focused on the area between the Chesapeake and Delaware Canal, the Delaware River, and the Maryland-Delaware border. Boundary conditions for these areas were derived from modeling studies completed by others over the past 10 years.

Compilation and review of data used for model input revealed gaps in hydraulic properties, pumping, aquifer and confining bed geometry, and water-level data. The model is a useful tool for understanding hydrologic processes within the study area such as horizontal and vertical flow directions and response of aquifers to pumping, but significant data gaps preclude its use for detailed analysis for water resources management including estimating flow rates between Delaware and adjacent states. The calibrated model successfully simulated groundwater flow directions in the Rancocas and Mt. Laurel aquifers as expected from the conceptual model. Flow patterns in the Rancocas and Mt. Laurel aquifers are towards local streams, similar to flow directions in the Columbia (water table) aquifer in locations where these aquifers are in close hydraulic connection.

Water-budget calculations and simulated heads indicate that deep confined aquifers (Magothy and Potomac aquifers) receive groundwater recharge from shallow aquifers (Columbia, Rancocas, and Mt. Laurel aquifers) in most of the study domain. Within shallow aquifers, groundwater moves toward major streams, while in the deep aquifers, groundwater moves
toward major pumping centers.

RI72 Geology and Extent of the Confined Aquifers of Kent County, Delaware

RI72 Geology and Extent of the Confined Aquifers of Kent County, Delaware

Ground water comprises nearly all of the water supply in Kent County, Delaware. The confined aquifers of the area are an important part of this resource base. The aim of this study is to provide an up-to-date geologic framework for the confined aquifers of Kent County, with a focus on their stratigraphy and correlation. Seven confined aquifers are used for water supply in Kent County. All occur at progressively greater depths south-southeastward, paralleling the overall dip of the sedimentary section that underlies the state. The two geologically oldest, the Mount Laurel and Rancocas aquifers, are normally reached by drilling only in the northern part of the county. The Mount Laurel aquifer is an Upper Cretaceous marine shelf deposit composed of clean quartz sands that are commonly glauconitic. It occurs at around 300 ft below sea level in the Smyrna Clayton area and is typically just less than 100 ft thick. Southward, toward Dover, it passes into fine-grained facies that do not yield significant ground water. The Rancocas aquifer is a Paleocene to Eocene marine unit of shelf deposits consisting of glauconite-rich sands with shells and hard layers. It occurs as high as 100 ft below sea level in northwestern Kent County and deepens southeastward, rapidly changing facies to finer-grained, nonaquifer lithologies in the same direction.

OFR24 Saturated Thickness of the Water-Table Aquifer in Southern New Castle County, Delaware

OFR24 Saturated Thickness of the Water-Table Aquifer in Southern New Castle County, Delaware

This map shows the saturated thickness of the water-table aquifer. This aquifer consists of the deposits of the Columbia Formation and those portions of the Magothy and Englishtown-Mt. Laurel formations, and Rancocas Group that are hydraulically connected with the Columbia deposits (see Groot, Demicco, and Cherry, 1983). For example, large, saturated thicknesses in the zone trending northeast-southwest near Townsend reflect the addition of the sands of the Rancocas Group to the total thickness of the sands of the overlying Columbia Formation.

OFR21 A Guide to Fossil Sharks, Skates, and Rays from the Chesapeake and Delaware Canal Area, Delaware

OFR21 A Guide to Fossil Sharks, Skates, and Rays from the Chesapeake and Delaware Canal Area, Delaware

In recent years there has been a renewed interest by both amateur and professional paleontologists in the rich upper Cretaceous exposures along the Chesapeake and Delaware Canal, Delaware (Fig. 1). Large quantities of fossil material, mostly clams, oysters, and snails have been collected as a result of this activity. Recent dredging (1978, 1981) by the United States Army Corps of Engineers has helped expose a rich vertebrate fossil assemblage. It includes representatives from the classes Reptilia, Osteichthyes, and Chondrichthyes. An extensive literature search has revealed that a wealth of information exists which would aid in the identification of the vertebrate fossils of Delaware.

Simulation of Groundwater Flow in Southern New Castle County, Delaware

Diagram of Conceptual Groundwater Flow Model
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To understand the effects of projected increased demands on ground water to supply water, a finite-difference, steady-state, nine-layer, groundwater flow model was used to simulate groundwater flow in the Coastal Plain sediments of southern New Castle County, Delaware. Results are published in DGS RI77

HM11 Ground-Water Recharge Potential Kent County, Delaware

Ground-Water Recharge Potential Kent County, Delaware

The ground-water recharge potential map of Kent 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.