(Connie Jo Discoe/McCook Daily Gazette)
Frank Kwapnioski of North Platte and Lincoln said that Nebraska's water use is out of balance in some places, "but, in most cases, its' not significant, and we can correct this."
The Alliance contends that Nebraska's water use is not so much over-developed as it is possibly misunderstood and under-managed.
The water balance concept has been used world-wide since geographer and climatologist C. W. Thornthwaite (1899-1963), a native of Bay City, Michigan, pioneered the water balance approach to water resource analysis to assess water needs for irrigation and other water-related issues.
Thornthwaite and John R. Mather called the water balance/water budget concept in their 1955 scientific paper, "The Water Balance," a methodology for estimating water surpluses and runoff, and the difference between surpluses and runoff, to estimate the amount of water required to recharge an aquifer.
Kwapnioski said that the water balance concept can be used in Nebraska to address extreme challenges to water management: water use and storage in times of drought and flooding in times of excess, and the variability in precipitation patterns and climate.
Nebraska's water supply has two sources:
* On average, about 2 million acre feet of water arrive annually as surface water from other states.
* About 93 million acre feet of water, on average, come annually in the form of precipitation (rain, snow, hail, sleet), Kwapnioski said, and that varies -- between the far northwest corner of the state to the extreme southeast -- from 60 to 140 million acre feet per year.
The average annual rainfall ranges from less than 16 inches in the Panhandle to 32 inches in the southeast corner of the state, according to Alliance documentation.
"We can't sustain a system without understanding how it works," Kwapnioski said.
He said that the water balance concept is based on this equation: I - O = ΔS (input, which is precipitation, minus output, which is consumption, equals change in storage).
It's similar to a checking account balance, Kwapnioski said: You have deposits (input) and withdrawals (output) and the result is a change in the account balance.
The water balance concept considers that 84 percent of water is consumed through evaporation (30 percent), transpiration through rain-fed crops, grasses and trees, and streamflow out of state. About 9 million acre feet leave the state as surface water outflow each year, Kwapnioski said. These three water consumers are not generally included in a standard U.S. Geological Survey water use pie chart inventory, which indicates that 67 percent of water use goes to irrigation. In a comprehensive water balance approach, irrigation use accounted for about 9 percent of the total consumption of water in 2005.
According to the Alliance: "Only about 17 percent of Nebraska land surface is irrigated. Supplemental irrigation consumes only about 8 million of the 82 million acre feet of water consumed on average annually in the state."
Kwapnioski said the water balance concept advocates the recapture of some of the 30 percent of water lost in evaporation, and, he said, no-till farming practices can help reduce such "no-value" or "low-value" consumptions.
Another farming practice discussed at the meeting because of its potential to save water is the possible conversion of rangeland, grasses and CRP (Conservation Reserve Program), which benefit from precipitation 12 months a year, to a crop that requires water only six months a year; or to crop rotation programs that grow only six months every two years. Crop residue would have to remain on the ground to protect it from erosion and reduce soil temperatures.
Other water savings are being found in remarkable advancements in dryland crop production, Kwapnioski said.
"All of these concepts require additional research before being considered for implementation in any water management plan," Kwapnioski said.
The Nebraska Water Balance Alliance believes that:
* Total water consumption must be limited to the total supply, or less.
* Local water consumption must be limited to the local supply, or less.
* Evaporation needs to be reduced.
* Increases in water storage and water storage capacity are needed.
* The available water supply must be better managed by reducing non-beneficial consumption to the greatest extent practical.
More about the water balance concept will be available in January on the Nebraska Water Balance Alliance website: www.nebraskawaterbalance.com