SCIACCA, JOHN E., and TIM AULT, International Technology Corporation, Martinez, CA

ABSTRACT: Time-Sequence Air-Photo Interpretation for CERCLA and RCRA Investigations: A Technique That Still Works

Many new remote sensing techniques are being developed and applied to environmental investigations. However, interpretation of standard vertical public and private sector aerial photography remains a highly useful, cost effective, and underused technique applicable to such investigations. This paper illustrates the successful use of time-sequence air-photo assessment to aid in a CERCLA remedial investigation and a RCRA facility investigation.

In the first case, interpretation of air photos provided an historical evaluation of a site reported to be a buried landfill. However, more than 40 borings drilled a the site did not discover any refuse or landfill material. The air photo interpretation revealed that (1) volatile organic hydrocarbon contamination in soil and vapor samples appeared to result from surface discharge of liquids, and (2) any landfill material present was removed during facility expansion more than 30 yr ago. As a result, the site was discounted from further consideration as a landfill, thereby reducing regulatory requirements for site closure.

In the second case, time-sequence air-photo assessment conducted for a toxic waste disposal site allowed (1) determination and mapping of the construction sequence and facility modification, and (2) evaluation of general disposal

practices historically conducted at the site. The interpretation also suggested disposal of refuse occurred along the western portion of the site, and that the refuse may have been mixed with fill during the expansion of the facility levee system. Subsequent field investigations confirmed the presence of refuse in impoundment levees, which is an important factor in the consideration of future closure design.

AAPG Search and Discovery Article #90992©1993 AAPG Pacific Section Meeting, Long Beach, California, May 5-7, 1993.