Monitoring Change at the Lower Darby Creek Area Superfund Site

A Collaborative Effort Between USGS, EPA, FAA, and FWS

By Woods Hole Coastal and Marine Science Center December 8, 2023

Partnering with the EPA, FAA, and the FWS, USGS scientists conducted the first of a series of small uncrewed aircraft system data collections documenting the changes in the Lower Darby Creek Area Superfund Site. This is a subset of a larger ongoing project led by the EPA to remediate contaminated areas and monitor changes throughout the Lower Darby Creek Area Superfund Site.

At the end of August 2023, USGS scientists partnered with the Environmental Protection Agency (EPA), Federal Aviation Administration (FAA), and the Fish and Wildlife Service (FWS) to collect data and observe changes at the Lower Darby Creek Area (LDCA) Superfund Site in southeastern Pennsylvania. These data allow scientists to monitor erosion patterns, structural changes, and potential areas of contamination.

Superfund sites are designated and managed by the EPA due to the presence of hazardous substances, pollutants, or contaminants that pose a health risk or threat to the environment.

The LDCA Site, located between Cobbs and Darby Creeks and the Delaware River, includes the Clearview Landfill and Folcroft Landfill, as well as the contaminated groundwater associated with them and the impacted aquatic environments in the adjacent creeks and wetlands, including portions of the John Heinz National Wildlife Refuge. Both landfills operated from the 1950s to the 1970s accepting municipal, demolition, and hospital waste, which was disposed of along the edges of the creek.

The USGS, EPA, FFA, and FWS are using small uncrewed aircraft systems (sUAS) to observe landscape changes over time. This includes vegetation coverage and topography changes over the recently completed forested evapotranspiration cover on the Clearview Landfill, thermal detection of groundwater discharge into the Darby Creek and local tributaries from potential contaminant sources, and topography changes and contaminated sediment transport modeling related to storm erosion in John Heinz National Wildlife Refuge. This is the first in a series of data collections documenting the changes in the area.

Group of people outside smiling at camera with drone on the ground — USGS sUAS pilots with Josh Barber from the EPA and a sUAS with the lidar payload mounted and ready to fly over the John Heinz Wildlife Refuge.

Large group of people outside smiling for photo with drone on the ground in front of them — Fish and Wildlife personnel participating in a demonstration by the WHCMSC about using sUAS to collect remotely sensed data.

What data were collected? And why are they important?

Lidar Data Collection:

The sUAS, equipped with lidar sensors, captured imagery of the surface of the Clearview Landfill, and parts of the refuge susceptible to coastal erosion. These data will provide a high-resolution 3D model, aiding in understanding the LDCA site's structural changes over time.

Thermal Imaging:

The sUAS also captured thermal imagery of the landfill and refuge. This will potentially allow groundwater seeps and thermal anomalies to be identified, which may identify discharge locations of groundwater to surface water and wetlands. This information is crucial for monitoring potential contamination and guiding targeted sampling planned for 2024.

Multispectral Data:

Multispectral data was collected using the sUAS, which captures images within specific wavelength ranges across the electromagnetic spectrum. These data were collected to perform vegetation classification and determine vegetation cover percentages. The data will help to monitor the health and progression of habitat on the Clearview evapotranspiration cover.

Baseline Dataset for Storm Erosion Detection:

A baseline dataset was created to address concerns about storm erosion and sediment resuspension. This will enable changes and erosion patterns to be monitored over time within the refuge.

Green and blue lidar map over black background — Preliminary lidar data collected in the John Heinz Wildlife Refuge as a baseline for future topography change.

Colorful elevation model of ClearView Landfill — A preliminary elevation model created by flying sUAS with a lidar scanner over the ClearView landfill.

Colorful lidar data map over black background — Preliminary lidar data collected in the John Heinz Wildlife Refuge as a baseline for future topography change.

This first series of data, coupled with future datasets, allows for better monitoring of the John Heinz National Wildlife Refuge. More detailed monitoring can ensure that communities surrounding the LDCA Superfund Site, tourists visiting the area, and wildlife can continue to use and enjoy the land safely.

To learn more about sUAS work, visit the USGS Aerial Imaging and Mapping website.

Background on the Lower Darby Creek Area Superfund Site

The EPA added the Lower Darby Creek Area Superfund Site to the Superfund National Priorities List in 2001. Since then, investigations have led to several cleanup actions to make this area safe for surrounding communities. Cleanup activities have included removing contaminated soil from residential yards and a City Park in the Eastwick neighborhood of Philadelphia, excavating and consolidating landfill waste under the Clearview Landfill evapotranspiration cover, and removing a high level of polychlorinated biphenyl waste that was posing a threat to nearby Darby Creek. The FWS manages the Refuge, which includes the Folcroft Landfill portion of LDCA. The John Heinz National Wildlife Refuge is the first urban wildlife refuge in the U.S. and has become a major tourism hub for the area. The Refuge provides interactive education opportunities, fishing, canoeing, and hiking in addition to the safe use of residential areas throughout the Eastwick Neighborhood.

To learn more about the LDCA Superfund Site, as well as other sites and the Superfund program itself, visit the EPA website.