Water Law 101: Part 4, Groundwater Terms and Definitions

Center pivot irrigation
Center pivot irrigation in Scotts Bluff County, Nebraska. (Photo by Gary Stone)

Water Law 101: Part 4, Groundwater Terms and Definitions

Part 4 of a six-part series about basic water law in the United States, predominately in the western part of the country, and how it affects this finite resource. Water law can be traced back to Roman times and also has roots in English common law. Across the United States, it varies from state to state, and from East to West. When conflicts arise, courts usually determine the outcome, unless there are state or federal laws or previous case studies to resolve the issue. Exceptions to the law can arise from differences in each state’s water laws.


Part 1: Basic concepts and legal terms, including riparian doctrine and prior appropriation.

Part 2: Other types of water rights and legal doctrines and concepts.

Part 3: Terms and definitions used in administering surface-water rights.

Part 4: Groundwater terms and definitions


Groundwater refers to subsurface water, as distinct from surface waterspecifically water in the saturated zone of an aquifer — the water stored underground in rock crevices and in the pores of geologic materials that make up the earth’s crust. Groundwater lies in the ground’s zone of saturation, and is also referred to as asphreatic water.

An aquifer is an underground layer of porous rock, sand, or gravel containing large amounts of water. The term is usually restricted to water-bearing structures capable of yielding enough water to constitute a usable supply. This is a geologic formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs.

Nebraska is rich in ground water due mainly to the Ogallala/High Plains aquifer.

There are different types of aquifers:

An Artesian aquifer, generally synonymous with confined aquifer, is bounded above and below by formations of impermeable or relatively impermeable material. Also described as an aquifer in which ground water is under pressure significantly greater than atmospheric and its upper limit is the bottom of a bed of distinctly lower hydraulic conductivity than that of the aquifer itself.

perched aquifer is a groundwater unit separated from the main groundwater supply by a relatively impermeable stratum and by the zone of aeration above the main water body.

Hydrologically connected groundwater is the flow that a perennially flowing stream reduces to during the dry season. It is supported by groundwater seepage into the channel or the discharge entering streams channels as effluent from the groundwater reservoir. 

In Nebraska, groundwater is managed by the 23 natural resources districts (NRDs).

Correlative (water) rights (or the California rule) refers to rights of landowners over a common groundwater basin that are coequal, or correlative, so that any one owner cannot take more than his share even if the rights of others are impaired. In the groundwater context, the doctrine of correlative rights generally limits the appropriation of groundwater to the landowner’s proportionate share of the water available — “share and share alike.”

However, some NRDs have implemented groundwater pumping restrictions that limit the amount of water that each irrigator can pump per year (or period of several years), for a certain number of acres. Sometimes these NRDs allow water that has not been utilized to be “moved” or “banked” and pumped from another well that the grower manages to meet the water needs of certain crops.

Reasonable use doctrine (the American rule) states that a water user can use as much groundwater as desired as long as the user is not wasting it (waste is per se or automatically unreasonable); and the water must be used on the land where the well is (the use of groundwater on non-overlying land is per se unreasonable). Otherwise there are no restrictions on pumping and a pumper cannot be stopped from drying up a neighbor’s well, unless the neighbor can prove that person is wasteful or that his use is non-overlying.

Subflow doctrine refers to when groundwater that is hydrologically connected to a stream is legally considered part of the stream, and therefore subject to surface water law (prior appropriation). The courts in Nebraska have not followed this rule.  

Templeton doctrine is one basis for surface water-groundwater interface policy. In this case, the surface irrigator drilled a well because the streamflows were declining (a common response to a common situation; other hydrologically connected wells were probably causing the streamflow to decline). The new well induced recharge from the stream (pumped water from the stream into the well). A New Mexico court treated this as a change in the appropriator’s point of diversion from the stream to the new well. This allowed the appropriator to transfer his senior priority date from the stream to the new well, a significant legal advantage. So, the otherwise junior well becomes a senior well.  

Induced recharge is the designed (as opposed to the natural or incidental) replenishment of groundwater storage from surface-water supplies. 

Artificial recharge is the addition of surface water to a groundwater reservoir by human activity, such as putting surface water into a spreading basin. It can also be the designed (as opposed to the natural or incidental) replenishment of ground water storage from surface water supplies such as irrigation or induced infiltration from streams or wells. There are five common techniques to effect artificial recharge of a groundwater basin: water spreading, recharge pits, recharge wells, induced recharge and wastewater disposal.


To repeat the question that concluded previous parts of this series: What is water worth?


NEXT: Groundwater, Part 2.

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