Unsaturated Zone [Energy] Law and Legal Definition

According to 10 CFR 60.2 (1) [Title 10 – Energy; Chapter I -- Nuclear Regulatory Commission; Part 60 -- Disposal of High-Level Radioactive Wastes in Geologic Repositories; Subpart A -- General Provisions], the term unsaturated zone means “the zone between the land surface and the regional water table. Generally, fluid pressure in this zone is less than atmospheric pressure, and some of the voids may contain air or other gases at atmospheric pressure. Beneath flooded areas or in perched water bodies the fluid pressure locally may be greater than atmospheric.”