The goal of the program was to identify and evaluate nondestructive monitoring techniques for their ability to detect a leak in either existing or planned waste impoundment liners. In the case of existing sites, any technique that might improve the limitations of conventional groundwater quality monitoring practices was identified. Thus, any technique that can detect the presence of leachate moving out from a site before it actually contacts the grounwater was identified. In planned sites, the 1 sq ft goal was identified as an ideal to work toward. Approximately 28 candidate geophysical techniques were reviewed in the literature survey. Of these, 20 were identified as having potential as leak detection techniques and were assessed during the ranking exercise.