(b) Favorable conditions.

1. (1) A surface-water system such that expected climatic cycles over the next 100,000 years would not adversely affect waste isolation.
2. (2) A geologic setting in which climatic changes have had little effect on the hydrologic system throughout the Quaternary Period.

(c) Potentially adverse conditions.

1. (1) Evidence that the water table could rise sufficiently over the next 10,000 years to saturate the underground facility in a previously unsaturated host rock.
2. (2) Evidence that climatic changes over the next 10,000 years could cause perturbations in the hydraulic gradient, the hydraulic conductivity, the effective porosity, or the ground-water flux through the host rock and the surrounding geohydrologic units, sufficient to significantly increase the transport of radionuclides to the accessible environment.