Groundwater contamination from waste management sites: The interaction between risk‐based engineering design and regulatory policy: 2. Results

The risk‐cost‐benefit analysis developed in the companion paper (J. Massmann and R. A. Freeze, this issue) is here applied to (1) an assessment of the relative worth of containment‐construction activities, site‐exploration activities, and monitoring activities as components of a design strategy for the owner/operator of a waste management facility; (2) an assessment of alternative policy options available to a regulatory agency; and (3) a case history. Sensitivity analyses designed to address the first issue show that the allocation of resources by the owner/operator is sensitive to the stochastic parameters used to describe the hydraulic conductivity field at a site. For the cases analyzed, the installation of a dense monitoring network is of less value to the owner/operator than a more conservative containment design. Sensitivity analyses designed to address the second issue suggest that from a regulatory perspective, design standards should be more effective than performance standards in reducing risk, and design specifications on the containment structure should be more effective than those on the monitoring network. Performance bonds posted before construction have a greater potential to influence design than prospective penalties to be imposed at the time of failure. Siting on low‐conductivity deposits is a more effective method of risk reduction than any form of regulatory influence. Results of the case history indicate that the methodology can be successfully applied at field sites.