Borehole Radar Monitoring of a Steam-Injection Remediation Pilot Study, Loring Air Force Base, Maine

[A comprehensive overview of this project is now available.]

As part of its applied research initiatives in FY2002, the USGS Office of Ground Water, Branch of Geophysics began geophysical monitoring of a steam-injection remediation pilot study at the Loring Air Force Base, Limestone, Maine.

The U.S. Air Force (USAF) is implementing a steam-injection remediation pilot study in fractured limestone contaminated with volatile organic compounds (VOCs). The purpose of the study is to evaluate the effectiveness of steam injection to flush the contaminated groundwater into extraction wells and to vaporize volatiles that can then be removed through a vapor extraction system. The Branch of Geophysics is conducting borehole-geophysical surveys to determine if borehole radar methods can be used to monitor steam- injection remediation.

For this study the Branch of Geophysics is conducting single-hole radar reflection and hole-to-hole radar tomography in monitoring wells. Temperature and electromagnetic-induction logs are also being collected to provide additional information that can be used to enhance the radar data analysis. Background geophysical logs were collected prior to the start of the steam injection, and additional logs were collected at two different times during the actual injection. The geophysical data will be used to develop mathematical models from which changes in the temperature and electrical conductivity of the subsurface may be able to be determined.

This research was funded by the US Environmental Protection Agency (USEPA) Region 1 and the USEPA Technology Innovation Office, with support from the USAF and the USGS Toxic Substances Hydrology Program.

View the online photo gallery from this project.