Hooper Springs Power Transmission Line, Caribou County, Idaho

Phase I Environmental Site Assessment
Sampling and Analysis Plan

Contaminated Media Management Plan


Anderson Geological, Inc. (AGI) completed a Phase I Environmental Site Assessment for Bonneville Power Administration (BPA) for a proposed 8-mile section of a power transmission line corridor in southeast Idaho. The corridor ran through an area of active and abandoned phosphate mines that were subjects of CERCLA investigations under the oversight of U.S. EPA, Idaho Dept. of Environmental Quality and the U.S. Forest Service. 

The purpose of the Phase I investigation was to identify issues of potential CERCLA liability associated with acquiring right of way in areas impacted by contaminants and also to identify and assess the business risk and additional expenses associated with handling and disposing of contaminated media (soil and groundwater) during construction of the transmission line. 

The primary contaminant found at the mine sites is selenium, which is a by-product of waste rock stockpiled near the mines. The groundwater near a section of the right of way was found to be impacted by a shallow contaminant plume of selenium. In another area, the right of way was possibly located near a former waste rock dump. Both of these issues represented potential issues of future CERCLA liability and elevated business risk due to potentially increased construction costs. 

AGI interviewed the regulators and landowners and evaluated the practices related to the proposed construction work, which would involve the generation of significant volumes of soil and water during the construction of the transmission line towers in the impacted areas. AGI wrote a Sampling and Analysis Plan for the characterization of the contaminants in the soil and water and a Contaminated Media Management Plan to provide guidance to BPA for the handling and disposal of contaminated soil and groundwater during construction.