The Delaware Geological Survey led a multi-agency, state and federal effort (including DelDOT, DNREC, USGS, and NOAA) to secure funds from the Hurricane Sandy Relief appropriation to collect new, high-quality LiDAR for the entire state of Delaware. LiDAR, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure distances from a source to a target object. Typically, a LiDAR device is attached to the bottom of a plane and is pointed at the ground.
In 2015, DGS became aware of a situation east of Dover where there is potential for overpumping of the Columbia aquifer by the City of Dover’s Long Point Road wellfield (LPRW) and numerous large-capacity irrigation wells in the surrounding area (Figure 1).
Monitoring wells and groundwater sensors were installed and monitored in and around Holts Landing State Park on the Indian River Bay, eastern Sussex County, Delaware, between October 2009 and August 2012. Data from test drilling, geophysical logging, geophysical surveys, and well testing characterized the hydrogeological framework and spatial and temporal patterns of water pressure, temperature, and salinity in the shallow, unconfined Columbia aquifer. The work revealed a plume of freshened groundwater extending more than 650 ft into the bay from the shoreline.
Geologic maps at the DGS are created as primary deliverables of a project and as derivatives of other projects. Primary deliverables are mainly those that are the result of outside funding sources such as the AASG-USGS cooperative StateMap. Derivative maps are those that have primary data collected for reasons other than geologic mapping can be used to create geologic maps or that geologic maps are derivative products of a project rather than the primary goal of a project.