[en] The Columbia River basalts underlying the Hanford Site in Washington State are being considered as a possible location for a nuclear waste repository. To establish the feasibility of this site, the performance of such a repository, which depends primarily on the hydrologic parameters of the site, must be evaluated for compliance with the applicable licensing regulations and guidelines. In this context, the hydrologic parameters of particular interest are the effective porosity and the ration of vertical-to-horizontal hydraulic conductivity, called the anisotropy ratio. 200 refs