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: "Middletown"

Finding faults - Delaware Geological Survey discovers evidence of past earthquakes

Delaware Geological Survey scientists found slickensides in core samples indicating faults in northern Delaware.

Delaware Geological Survey (DGS) scientists have uncovered hard proof of faults in northern Delaware, indicating the occurrence of earthquakes millions of years ago.

Scientists dig deep to research aquifers

Andy Burkart pulls the cap off the pipe that contains a soil sample and anything else in the hole - The News Journal/ROBERT CRAIG

Delaware Geological Survey is installing two new research and monitoring wells for northern Kent County and southern New Castle County. The project, which will take about two years, calls for eight new wells, including Smyrna, the Woodland Beach, Middletown and Townsend areas, two sites in Blackbird State Forest, Cedar Swamp and a location near Odessa National Country Club.

Monitoring our water - Delaware Geological Survey improving groundwater monitoring efforts with new wells, sampling

Scott Andres examines sediment samples extracted from more than 500 feet underground for clues about the amount and quality of water available in central Delaware.

Delaware Geological Survey improving groundwater monitoring efforts with new wells, sampling. Scientists are digging for answers about the amount and quality of water available underground in central Delaware, where ongoing development will put increasing demands on water supplies in the coming decade.

The Delaware Geological Survey (DGS) is installing 7,700 feet of wells at eight sites in southern New Castle and northern Kent counties to improve groundwater-monitoring efforts, supported by a $600,000 grant from the Delaware Department of Natural Resources and Environmental Control (DNREC). Groundwater is the primary source of drinking water south of the Chesapeake and Delaware Canal, and populations there are projected to continue expanding.

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.

Number of Pages: 
18

RI35 Unconformities in the Fluvial Columbia Sediments Revealed by Thin Pebble Beds

RI35 Unconformities in the Fluvial Columbia Sediments Revealed by Thin Pebble Beds

An explanation is suggested for the origin of thin, laterally persistent pebble beds commonly found in the Columbia Formation of Delaware. The pebbles in the thin beds are usually less than 16 mm in diameter, well rounded, spherical, and composed mainly of resistant material: chert, vein quartz, and quartzite. The process thought to be responsible for the origin of these beds is a combination of erosion and transport of sand and pebbles in suspension by highly turbulent streams resulting in selective deposition of pebbles in thin, laterally persistent layers. An attempt is made to estimate quantitatively the amount of sand that has to be eroded to produce thin pebble beds. The results suggest that such pebble beds mark significant erosional unconformities within the fluvial Columbia sequence.

This page tagged with:

B13 Geology, Hydrology, and Geophysics of Columbia Sediments in the Middletown-Odessa Area, Delaware

B13 Geology, Hydrology, and Geophysics of Columbia Sediments in the Middletown-Odessa Area, Delaware

Columbia sediments in the Middletown-Odessa area are composed of boulders, gravels, sands, silts and clays. These sediments are exposed in four gravel pits where their structures and textures were studied. Subsurface geology was interpreted on the basis of the well-log data from 40 holes drilled in the area of study. Columbia sediments were laid upon a surface made up of the greensands of the Rancocas Formation (Paleocene – Eocene age). The contact between the Rancocas and Columbia Formations is an erosional unconformity.

GM13 Geologic Map of New Castle County, Delaware

GM13 Geologic Map of New Castle County, Delaware

This map shows the surficial geology of New Castle County, Delaware at a scale of 1:100,000. Maps at this scale are useful for viewing the general geologic framework on a county-wide basis, determining the geology of watersheds, and recognizing the relationship of geology to regional or county-wide environmental or land-use issues. This map, when combined with the subsurface geologic information, provides a basis for locating water supplies, mapping ground-water recharge areas, and protecting ground and surface water. Geologic maps are also used to identify geologic hazards, such as sinkholes and flood-prone areas, to identify sand and gravel resources, and for supporting state, county, and local land-use and planning decisions.

Map Scale: 
100,000
This page tagged with: