Delaware Groundwater Monitoring Network

Project Status

Water levels are critical data for evaluating groundwater resource management. These data aid in the analyses of aquifer response to pumping, climatic variability, drought, saltwater intrusion, and interaction with steams and surface waters. Long-term, time-series water level datasets serve as baseline data and allow for trend assessment.

The Delaware Geological Survey (DGS) currently monitors groundwater level, temperature, and salinity in a network of wells in Delaware. This project is supported by, and in cooperation with, the Delaware Department of Natural Resources and Environmental Control (DNREC). The DGS works cooperatively with other state agencies, such as the Delaware Solid Waste Authority (DSWA) and the Delaware Environmental Observing System (DEOS), to provide telemetered real-time data from four wells. As of 2024, the monitoring network consists of over 120 monitoring wells covering 17 major aquifers. Most sites have multiple monitoring wells, each well installed at a different depth. The majority of the wells have data loggers installed, and water levels are collected by the data logger every 15 minutes. DGS staff routinely visit the wells – generally monthly or quarterly – to collect water level data and download logger data. Groundwater quality samples are collected from a sub-set of network wells, with most wells being sampled every five years. We are in the process of equipping more wells with telemetered real-time instrumentation.

Collected data are maintained in a relational database and served to stakeholders via a web interface. The DGS database holds over half a million manually measured water levels, and over 38 million logger-measured groundwater levels, adding over 2.7 million records each year. In addition, automated data loggers have generated nearly 13 million groundwater-temperature records and over 7 million salinity records. These data support evaluation of the long-term availability and sustainability of Delaware’s groundwater supply, management of the resource, and a myriad of uses by the environmental management, engineering, and research communities.

Improvements to this network include installing new monitoring wells in southern New Castle County and northern Kent County in 2013-2014 and in central and southern Kent County in 2017-2020. In 2024, we received additional funding to expand the well network in Sussex County.

Learn more about our data collection operating procedures in this Open-File Report.

Last updated: January 2024