ABSTRACT
Groundwater law in the United States has aspects existing at all jurisdictional levels: local, state and federal. Differences are emphases on groundwater quantity versus groundwater quantity and quality, irrigation use compared to total groundwater use and ecosystem consideration. The condition of groundwater mobility affecting quality and quantity influences the effects that one user may have on a neighboring user that may carry with it costs and/or benefits depending on the nature of the use. Currently in the United States, 50 state groundwater doctrines have evolved, although some are quite similar. The doctrine related to groundwater quantity has a local focus, having evolved from English court law and ultimately into state law. Legal terms for groundwater categories are important in understanding some of the legal and hydrologic issues associated with these doctrines. An underground stream follows a definite channel below the ground surface.
