Long time-series of water levels in major aquifers serve as critical baseline data for resource management and analyses of aquifer response to pumping, climatic variability, drought hazards, seawater intrusion, and interaction with streams and their ecosystems. To this end the Delaware Geological Survey (DGS) currently monitors groundwater level, temperature, and salinity in a network of wells in Delaware. The number of wells fluctuates annually with funding and staffing resources. Data from network wells are maintained in a relational database and served to stakeholders via a web interface. As of December 2017, the DGS database holds over 19 M instrument measured and nearly 33 K manually measured groundwater levels. Instrumentation has generated over 130 K temperature and 500 K specific conductance 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 science communities.
A recent project done at the request of the Delaware Water Supply Coordinating Council (WSCC) added more than 20 wells to the network in southern New Castle and northern Kent Counties. A similar three-year project was funded in fiscal year 2017 to add over 40 wells in Kent County. As part of this project we are automating data collection, reduction, and archiving to increase efficiency and quality control while sustaining the statewide network over time. We are inspecting the condition of wells in the current monitoring network in addition to inspecting wells that may be included at a later date, using down-hole videos, slug tests, and wellhead security assessments.
In anticipation of needs to monitor for saltwater instrusion we deployed and are testing operations of salinity sensors in several wells along the Atlantic and Delaware Bay coasts. We are seeking resources to expand monitoring to include routine groundwater quality sampling and analyses.