Borrow pit issues and land management at a DOE lab

The INL site is a large DOE facility that encompasses a variety of resources and historical sites and uses. Within the requirement of federal regulations these resources need to be balanced with ongoing operational requirements. An example is the need to collect information from a prehistoric site prior to development at the INL rifle range. This particular cultural survey was able to employ geophysics prior to archeological excavation to help guide the limited nature of the investigation. In addition to regulated land releases such as with cultural issues, geophysics has also played a role in planning for current and future land use with respect to borrow pit operations supplying capping material to the ongoing INL cleanup projects. The Ryegrass Flats borrow area, a 600 acre site currently tasked with supplying these materials, consists of an average of 15 feet of aeolian sediment overlying basalt bedrock. Several issues about this source area became apparent during operations in the initial forty acre pit, including unexpected shallow bedrock outcroppings and a clear possibility of UXO contamination. To address bedrock depth a field study employing seismic refraction was used to better define the direction of future operations, and magnetic gradiometry was used for UXO detection over the next 40 acres of active site expansion. In both these studies, geophysics was instrumental in planning sampling and identifying issues relevant to planned operations.