This week’s short post is on groundwater law – from the viewpoint of physics. Water policy, management, and human law often misunderstand how groundwater and surface water work physically. Bredehoeft, et al. (1982) distill a longstanding lament of many groundwater experts, “Perhaps the most common misconception in groundwater hydrology is that a water budget of an area determines the magnitude of possible groundwater development. Several well-known hydrologists have addressed this misconception and attempted to dispel it. Somehow, though, it persists and continues to color decisions by the water-management community.”