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Site content related to keyword: "groundwater"

OFR29 Sources of Ground-Water Contamination in Delaware

OFR29 Sources of Ground-Water Contamination in Delaware

Ground water is Delaware's most important natural resource. Our aquifers, which are present everywhere in Delaware, provide more than 75 million gallons each day for all uses. Nearly all of the water used in Delaware south of the Chesapeake and Delaware Canal is obtained from aquifers, both water-table and artesian. An appreciable quantity of water is also obtained from aquifers in northern New Castle County. Ground water has generally been of good quality, been used with little or no treatment, and has been readily available at low cost.

OFR28 Potential for Ground-Water Recharge in the Coastal Plain of Northern New Castle County, Delaware

OFR28 Potential for Ground-Water Recharge in the Coastal Plain of Northern New Castle County, Delaware

This map was constructed primarily to indicate the possibilities for artificial recharge into both the surficial sediments of Quaternary age (exclusive of soils) and the older, immediately underlying sediments. However it can also be used to determine where natural recharge might be entering the ground most readily in those areas relatively free from impermeable cover. The surficial sediments include micaceous sands and gravels in the vicinity of the Fall Line derived from underlying crystalline rocks, Holocene marsh deposits, Delaware River sediments, and the Columbia Formation of Pleistocene age. The Columbia Formation is composed of poorly sorted sands with some gravels, silts and occasional clays. The unit is one of the most important ground-water reservoirs in New Castle County.

OFR25 Saturated Thickness of the Columbia Formation in Southern New Castle County, Delaware

OFR25 Saturated Thickness of the Columbia Formation in Southern New Castle County, Delaware

This map shows the saturated thickness of the Columbia Formation. The Columbia Formation covers most of the Coastal Plain of Delaware. Because it consists primarily of coarse sand, it is important to the hydrology of the area. It is an important groundwater reservoir and in most places water must pass through it to reach deeper units. The water budget of the Columbia Formation also influences runoff and baseflow components of streamflow. The saturated thickness was determined through interpretation of data in publications and files of the Delaware Geological Survey, United States Geological Survey, and the Water Resources Center of the University of Delaware. The thicknesses shown on the map represent the best judgment of the authors based on available data. Detailed investigations of specific sites will require additional data.

B16 Ground-Water Resources of the Piney Point and Cheswold Aquifers in Central Delaware as Determined by a Flow Model

B16 Ground-Water Resources of the Piney Point and Cheswold Aquifers in Central Delaware as Determined by a Flow Model

A quasi three-dimensional model was constructed to simulate the response of the Piney Point and Cheswold aquifers underlying Kent County, Delaware to ground-water withdrawals. The model included the Magothy, Piney Point, Cheswold, and unconfined aquifers, and was calibrated using historical pumpage and water-level data. Model calibration was accomplished through the use of both steady-state and transient-state simulations.

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.

B14 Hydrology of the Columbia (Pleistocene) Deposits of Delaware: An Appraisal of a Regional Water-Table Aquifer

B14 Hydrology of the Columbia (Pleistocene) Deposits of Delaware: An Appraisal of a Regional Water-Table Aquifer

The Columbia (Pleistocene) deposits of Delaware form a regional water-table aquifer, which supplies about half the ground water pumped in the State. The aquifer is composed principally of sands which occur as channel fillings in northern Delaware and as a broad sheet across central and southern Delaware. The saturated thickness of the aquifer ranges from a few feet in many parts of northern Delaware to more than 180 feet in southern Delaware. Throughout 1,500 square miles of central and southern Delaware (75 percent of the State's area), the saturated thickness ranges from 25 to 180 feet and the Columbia deposits compose all or nearly all of the water-table aquifer.

B11 Ground-Water Resources of Southern New Castle County Delaware

B11 Ground-Water Resources of Southern New Castle County Delaware

Southern New Castle County has a land area of 190 square miles in north-central Delaware. It is predominantly a rural area with a population of about 9,000 people who are engaged chiefly in agriculture. By and large, the residents are dependent upon ground water as a source of potable water. This investigation was made to provide knowledge of the availability and quality of the ground-water supply to aid future development. The climate, surface features, and geology of the area are favorable for the occurrence of ground water. Temperatures are generally mild and precipitation is normally abundant and fairly evenly distributed throughout the year. The topography of the area is relatively flat and, hence, the streams have low gradients. The surface is underlain to a considerable depth by highly permeable unconsolidated sediments that range in age from Early Cretaceous to Recent.

B10 Salinity of the Delaware Estuary

B10 Salinity of the Delaware Estuary

The purpose of this investigation was to obtain data on and study the factors affecting the salinity of the Delaware River from Philadelphia, Pa., to the Appoquinimink River, Del. The general chemical quality of water in the estuary is described, including changes in salinity in the river cross section and profile, diurnal and seasonal changes, and the effects of rainfall, sea level, and winds on salinity. Relationships are established of the concentrations of chloride and dissolved solids to specific conductance. In addition to chloride profiles and isochlor plots, time series are plotted for salinity or some quantity representing salinity, fresh-water discharge, mean river level, and mean sea level. The two major variables which appear to have the greatest effect on the salinity of the estuary are the fresh-water flow of the river and sea level. The most favorable combination of these variables for salt-water encroachment occurs from August to early October and the least favorable combination occurs between December and May.

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.

B6 The Water Resources of Northern Delaware

B6 The Water Resources of Northern Delaware

Northern Delaware, the area above the Chesapeake and Delaware Canal in New Castle County, is an area of rapidly growing population and expanding industry. In some places the demand for water has reached or exceeded the capacity of the existing facilities creating apparent water shortages. Many agencies, both public and private, are attempting to alleviate these shortages; studies are being made and reports prepared for immediate action as well as long-term planning. It is the purpose of this report to examine on a long-range basis the water resources of the northern Delaware area. This examination indicates that the surface-water and groundwater resources of the area far exceed the 72.8mgd (million gallons per day) used during 1955. The amount of ground water potentially available in the area is estimated to be at least 30 mgd and the amount of surface water potentially available depends principally on the amount of storage that may be feasible economically. Storage of 3 million gallons per square mile would provide an allowable draft rate of 140 mgd with a deficiency at average intervals of ten years, while storage of 30 million gallons per square mile would raise the allowable draft to 250 mgd, which is about half of the mean annual discharge. In addition to the fresh-water resources, saline water from the Delaware River and its tidal estuaries is available in almost unlimited quantity for cooling, fire fighting, some types of washing, and other purposes.

B4 Preliminary Report on the Geology and Ground-Water Resources of Delaware

B4 Preliminary Report on the Geology and Ground-Water Resources of Delaware

Delaware has an abundant supply of ground water of a quality suitable for most purposes. About 30 million gallons of water a day was pumped from the ground in 1954. It is estimated that this is roughly 1/16 of the optimum yield. This water is derived from nine groups or series of water-bearing units and is obtained from wells which yield as much as 1,100 gallons per minute. Thousands of wells serve agriculture, industry, municipalities, and domestic users. Geographically, Delaware is situated along the Atlantic coast of the United States in two physiographic provinces: the Piedmont and the Coastal Plain. The Piedmont is a belt of rolling foothills of the Appalachian Mountains. It is separated from the Coastal Plain by the Fall Line, a narrow zone of rapids or falls along which rivers and creek descend rapidly from the mature valleys of the Piedmont to the sluggish tidal estuaries of the coastal area. The Coastal Plain is a flat or gently undulating plain of relatively low altitude, which borders the Atlantic Ocean and its estuarine embayments.

B2 Geology and Ground-Water Resources of the Newark Area, Delaware with a Section on the Surface Water Resources

Geology and Ground-Water Resources of the Newark Area, Delaware with a Section on the Surface Water Resources

This report describes the geological and lithological conditions in the Newark area, and the occurrence, quantity, and quality of the available ground-water supply. Newark is located on the Fall Line, the boundary between the rolling hills of the Piedmont on the north and the gentle slopes of the Coastal Plain on the south. Because the Piedmont is underlain by dense crystalline rocks and their weathered clayey soils, which are of low water-bearing capacity in contrast to the more permeable silts and sands of the Coastal Plain, the exploration for ground water was confined to the Coastal Plain south and southeast of Newark.

RI25 Selected Logging Data and Examples of Geophysical Logs for the Coastal Plain of Delaware

RI25 Selected Logging Data and Examples of Geophysical Logs for the Coastal Plain of Delaware

Geophysical logging techniques have been used in Delaware for many years as a means of identification and correlation of Coastal Plain formations. Criteria for the recognition of those formations having distinctive types of logs are presented. Formation factors have been calculated using multiple-point resistivity logs, temperature logs, and ground-water quality data and range from 1.2 to 6.8 for various formations underlying the State. Formation factors in turn are used to estimate water quality in later test holes.

SP27 Water Table in the Inland Bays Watershed, Delaware

SP27 Water Table in the Inland Bays Watershed, Delaware

This poster shows three different map views of the water table as well as information about how the maps were made, how the depth to water table changes with seasons and climate, and how the water table affects use and disposal of water. The map views are of depth to the water table, water-table elevation (similar to topography), and water-table gradient (related to water flow velocity).

SP17 The Delaware Geological Survey: The Formative Years, 1951-1969

SP17 The Delaware Geological Survey: The Formative Years, 1951-1969

Emphasis is placed herein on the years of Dr. Groot's leadership of the Survey. The remarkable work of James C. Booth in the last century is acknowledged but has elsewhere been entered in history. Some continuing activities of the Survey after 1969 are noted together with comments of an experienced observer; this current period may someday receive the attention of a recorder having the enhanced perspective of time.

SP8 Memoir of the Geological Survey of the State of Delaware

SP8 Memoir of the Geological Survey of the State of Delaware

The following report of the geological survey of the state of Delaware, conducted in the years 1837 and 1838, embraces all the observations and examinations which were made during the continuance of the survey, including those contained in the first and second annual reports, already laid before the legislature.

SP1 The Story of Your State Geological Survey's Search for Water

SP1 The Story of Your State Geological Survey's Search for Water

This is a brief story about water and the ways in which the Delaware Geological Survey helps insure that you will always have a plentiful supply of this precious natural resource.

Introduction to the Hydrogeology of Delaware

Brandywine Creek

Delaware’s water, both ground and surface, is one of its most important natural resources. As Delaware’s lead earth science agency, the Delaware Geological Survey provides information to inform and educate resource managers and the public to better understand and manage our water resources.

Simulation of Groundwater Flow in Southern New Castle County, Delaware

Diagram of Conceptual Groundwater Flow Model
Project Contact(s):

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

RI22 Hydrogeology of Selected Sites in the Greater Newark Area, Delaware

RI22 Hydrogeology of Selected Sites in the Greater Newark Area, Delaware

Additional sources of ground water have been located in the Piedmont Province as a result of a ground-water exploration program conducted by the Delaware Geological Survey at the University of Delaware in cooperation with the City of Newark. Drilling sites for relatively high-yielding wells were located through the use of geophysical investigations, air-photo interpretation, field mapping, and review of existing data.