Groundwater and Saline Water Intrusion Monitoring Network Infrastructure Improvements: Kent County, Delaware

Project Status
DGS has begun a three year project to install new water monitoring infrastructure and collect baseline data in Kent County, Delaware. Recommended by the Water Supply Coordinating Council in 2015, the project was funded by a fiscal year 2017 State of Delaware Capital Appropriation.


Expansion of water monitoring infrastructure in Kent County is critical because existing infrastructure is sparse and because population, economic, and environmental conditions, and agricultural practices (irrigation) have changed how we use water since previous regional studies were completed in the 1960s and 1970s. In addition, we now have more detailed understanding of aquifers and confining beds and vastly improved computer methods to simulate, analyze, and predict the availability of groundwater and the impacts of increased groundwater use. Completion of the proposed project will address the issue that existing wells are too sparsely distributed and data are not temporally adequate to support the use of these computer methods for the major water supply aquifers in Kent County. In recognition of the close links between groundwater and surface water and the potential for wells to become contaminated by saline streams, water monitoring infrastructure will be placed in both wells and streams. Moreover, this joint monitoring approach is important because of the linkage between sea-level rise and landward migration of saltwater.

A primary objective of this project is to construct new groundwater monitoring infrastructure in the Rancocas, Piney Point, Cheswold, Federalsburg, Frederica, Milford, and Columbia aquifers and surface water monitoring infrastructure in selected streams in Kent County, Delaware (Figure 1). Salinity monitoring sensors will be installed near and below the head of tide on selected streams and determine the frequency and magnitude of high salinity events. Stream gages will be re-established at two sites where development of new groundwater supplies has likely altered the balance between surface water and groundwater. Key planning elements for new well sites are 1) filling spatial gaps in the existing network, 2) obtaining permissions to install wells on state-, county- or locally-owned lands, with the goal that these wells will be accessible for decades, 3) well site locations that are not strongly influenced by daily pumping cycles of large production wells, and 4) locations where measurements can be made safely and efficiently.

Following installation, we will begin collecting baseline hydrologic, water quality, and hydraulic information that addresses near-term (10 year) critical water resource management issues. This includes manual and automated measurements of ground and surface water levels, temperature, and salinity, collection of samples for water quality analysis, measurement of aquifer hydraulic properties, and measurement of geophysical properties of aquifers and confining beds.

The project is being done in cooperation with the Delaware Department of Natural Resources and Environmental Control – Water Supply Section. Our partners at the US Geological Survey (USGS) are providing stream gaging services. Work is being coordinated with the Maryland Geological Survey.

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