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Browsing Open File Reports by Subject "aquifers"
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Item Characterization Of The Potomac Aquifer, An Extremely Heterogeneous Fluvial System In The Atlantic Coastal Plain Of Delaware(Newark, DE: Delaware Geological Survey, University of Delaware, 2004) McKenna, T.E.; McLaughlin, P.P.; Benson, R.N.Fluvial sands of the subsurface Cretaceous Potomac Formation form a major aquifer system used by a growing population in the northern Coastal Plain of Delaware. The aquifer is extremely heterogeneous on the megascopic scale and connectivity of permeable fluvial units is poorly constrained. The formation is characterized by alluvial plain facies in the updip section where it contains potable water. While over 50 aquifer tests indicate high permeability, the formation is primarily composed of fine-grained silt and clay in overbank and interfluvial facies. Individual fluvial sand bodies are laterally discontinuous and larger-scale sand packages appear to be variable in areal extent resulting in a labyrinth style of heterogeneity. The subsurface distribution of aquifers and aquitards has been interpreted within a new stratigraphic framework based on geophysical logs and on palynological criteria from four cored wells. The strata dip gently to the southeast, with generally sandy fluvial facies at the base of the formation lapping onto a south-dipping basement unconformity. The top of the formation is marked by an erosional unconformity that truncates successively older Potomac strata updip. Younger Cretaceous units overly the formation in its downdip area. In the updip area, the formation crops out or subcrops under Quaternary sands.The fine-grained facies include abundant paleosols that contain siderite nodules and striking mottling that commonly follows ped faces and root traces. These paleosols may serve as regional aquitards. This geologic complexity poses a challenge for determining the magnitudes and directions of ground-water flow within the aquifer that are needed for making informed decisions when managing this resource for water supply and contaminant remediation.Item Kent County Groundwater Monitoring Project: Results of Subsurface Exploration(Newark, DE: Delaware Geological Survey, University of Delaware, 2019-09) Andres, A.S.; McQuiggan, R.W.; He, C.This report documents the methods and results derived from subsurface exploration, monitoring well installation, and hydraulic testing conducted during the project "Groundwater and Saline Water Intrusion Monitoring Network Infrastructure Improvements: Kent County, Delaware". This project was focused on the aquifers in Kent County that supply water to wells for domestic, public, irrigation, and commercial uses as well as provide base flow to local streams. From shallowest to deepest, they are the Columbia, Milford, Frederica, Federalsburg, Cheswold, Piney Point, Rancocas, and Mt. Laurel aquifers.