By Justin Isherwood

Modern center pivot irrigation began in Nebraska, Frank Zyach of Columbus the acknowledged inventor of the center pivot.  Ironically Nebraska is considered an arid state along with Colorado and Kansas.  Average rainfall is 22”, if highly variable across the state.   The current number of farms is 46,800 (Wisconsin is 70,000) on 46.5 million acres, 8.5 million irrigated, the most of any state, with some 50,000 center pivots, 100,000 registered wells.  Well density of the Central Platte is 16 hi-caps per square mile.

When it comes to irrigation, numbing numbers are involved:

12,200 million gallons per day

4,390 million gallons from surface water

2,820 million gallons hydroelectric

8,790 million gallons irrigation

7,860 million gallons from groundwater, 94% for irrigation

72% of Nebraska irrigation is center pivot (2009), 70% corn, 19% soybeans

Irrigation started in the 1930s with the formation of the Central Nebraska Public Irrigation District of the South Platte, using water from Lake McConaughy for 213,000 acres and four hydro-plants.  The system went operational in 1941 on 44,000 acres.  Its canal system still functions.

Platte River water is pumped into Lake McConaughy with 40,000 acre feet of capacity.  During irrigation season the water is released to the E65 canal at 365 ft³ per second.  Together with the Phelps Canal they deliver 1300 cfs of irrigation water.  Part of the system’s current use is to provide for groundwater recharge and stabilize the Ogallala water table adjacent to the service area.  Groundwater under the Central Nebraska area has risen 10 feet since 1941.  Counties outside this area have experienced decline of 5 to 30 feet in the last 60 years.

In 1969 the Nebraska legislature passed LB1357 establishing Natural Resource Districts, a network of 25 districts allied to river basins across the state.  These management districts now claim Nebraska groundwater levels are less than a foot down from pre-irrigation levels in the 1950s, with some areas actually higher.

The Nebraska claim is counter to the experience of other Ogallala states, to cite that Nebraska has 37% of the Ogallala’s land surface and 65% of the total Ogallala water volume with a saturated thickness from 200’ to 1200’ and 8.5 million irrigated acres.

In the 1960s the rise of irrigation was apparent in Nebraska, and the state was aware it needed to protect the resource.  The Natural Resource Districts developed water allocation for irrigation as well as moratoriums on new wells specific to local management issues.  Nebraska’s initial irrigation was via field (gravity) flooding whose routine water use was in the 30 inch range.  Center pivots reduced this water use by a third to a half, 10-15 inches (10 inches being the Wisconsin average).  These Districts (NRD) have taxing authority to raise money to cost-share on water saving technology, co-op innovation and research into local issues.

In 2005 the Nebraska Supreme Court ruled in Spear Ranch v. Knaub there exists a legal connection between groundwater pumping and surface water.  With the empathy of the law going to surface water rights that had initiated the suit to redress sharp declines in Pumpkin Creek.  The court concluded “…after assessment  of the purpose of the water use, the economic value of the use, the social value of the use and the protection of existing values, uses, investments and enterprises that the justice was in requiring the user causing harm to bear the cost of repair.”

Nebraska is ground zero of the groundwater irrigation issue.  Nebraska pumps more groundwater for more cropland, with more center pivots than any other state.

In the continuing Central Wisconsin debate over groundwater, its public, its irrigators, its legislature, its attorney general, we would be wise to mind what Nebraska does.