LINCOLN — The Platte River threatens to leak reservoirs of red ink unless Nebraska can put more water in its longest stream.
Now an idea has emerged that could save hundreds of millions of dollars while maintaining crop irrigation, conserving wildlife habitat and protecting drinking water supplies for more than half the state's population, including Omaha and Lincoln.
Leaders of two natural resources districts recently announced the plan, convinced it could save money and water. The idea immediately caught the attention of key players in Nebraska water policy, although it remains to be seen whether it will gain momentum.
“If they can pull this off ... people will come from all over the world to study this, so it's a big deal,” said David Aiken, a water law authority at the University of Nebraska-Lincoln.
The proposal could create a global case study on balancing competing water demands, he said.
What sounds like a silver bullet for one of Nebraska's most vexing water problems, however, faces significant challenges of its own — namely, it calls for an unprecedented shift in the way the state's largest irrigation district does business.
An analysis conducted by a private engineering firm suggests that substantial amounts of water could be saved by irrigating farmland in south-central Nebraska with groundwater instead of surface water.
The Central Nebraska Public Power and Irrigation District, which manages the irrigation system, would have to approve the idea if it is to get beyond a PowerPoint presentation.
The district will hold a meeting Friday at its headquarters in Holdrege to learn more about the concept. Don Kraus, the district's manager, sounded skeptical about an idea he has only seen described in a three-page press release.
“The big-picture issue is, what kind of a threat does this pose to the long-term viability of irrigated agriculture in our area?” he said.
The district's cooperation is a deal breaker because it holds the legal right to water stored in Lake McConaughy and delivered to crop fields by an extensive network of canals and smaller reservoirs.
The irrigation district and the NRDs are working to boost flows in the Platte in coming years. Nebraska has agreed to do so under a recovery plan with Wyoming, Colorado and the federal government to help threatened and endangered species such as whooping cranes, least terns and pallid sturgeons.
Under the agreement, the states must return flows equaling about 150,000 acre-feet of water to the Platte during critical habitat times by 2019. An acre-foot equals about 326,000 gallons.
So far, water managers have put about 80,000 additional acre-feet into the river. Finding the next 70,000 acre-feet of water will prove more challenging and costly, said Ron Bishop, manager of the Central Platte NRD in Grand Island, which, along with the Twin Platte NRD in North Platte, sponsored the analysis.
A few possibilities now on the table include building new storage reservoirs, paying farmers to stop irrigating or building canals to transport water from other watersheds. By some estimates, those options could cost as much as $500 million, Bishop said.
Converting from surface water to groundwater irrigation, however, could return an additional 100,000 acre-feet of water in the Platte, according to the NRD analysis.
The analysis estimated that 400 to 450 new irrigation wells would have to be drilled to replace surface water irrigation. It did not, however, estimate how much those wells, along with new center pivots, would cost.
Assuming a new well and pivot system could be installed for about $100,000, the total cost of the conversion could add up to $40 million or more.
“If the studies that we've done are anywhere near right, it's really a win-win for everybody,” Bishop said.
Funds to pay for the conversions would come from the NRDs' taxing authority, taxes on irrigators and cost-sharing from the state's Water Resources Cash Fund, Bishop said.
Surface water irrigation relies on canals, ditches and gravity to flood fields with water. It is far less efficient than center-pivot irrigation systems, which pump water from underground and spray it on crops like giant sprinklers.
Although the irrigation canals would no longer carry water to fields in July and August, they would be used during cooler months to replenish aquifers depleted by hundreds of new irrigation wells, Bishop said.
Water would seep beneath the canals, gradually filtering into aquifers. Using the canals in the off-season also can significantly reduce water lost through evaporation.
As another benefit, some of the water from the recharged aquifer would find its way back to the Platte. Such groundwater recharge constitutes what resource professionals call “conjunctive use management” because it exploits the hydrological relationship between groundwater and surface streams.
The Central district would still hold a legal right to the water, under the proposed change, Bishop said. And it would not result in fewer irrigated acres, he added.
Changing the timing of releases from Lake McConaughy would allow managers to maintain a more constant level in the state's largest reservoir during the main summer recreation months, Bishop said. And the analysis showed no net loss in hydropower generation under changed management.
Finally, increased flows will help protect drinking water wells maintained by cities such as North Platte, Kearney, Grand Island, Lincoln and Omaha in the Platte Valley. The wellfields all require water flowing in the Platte to function properly and keep municipal supplies clean.
“There's potential for tremendous benefits for everybody in the central and eastern parts of the state,” Bishop said.
Jerry Kenny, director of the Platte River Recovery Implementation Program, said he agrees the concept holds potential and deserves to be explored in detail.
As for how much money it could save Nebraska and the federal government, he could only say he's looked at other conjunctive management projects that proved less expensive than alternatives.
“Water's not cheap, and it's not getting cheaper,” he said.
Brian Dunnigan, director of the Nebraska Department of Natural Resources, said he didn't know enough about the NRDs' proposal to comment on it. However, he said, smaller conjunctive use projects in Nebraska have already saved water.
“In general terms, it can be a benefit to all water users,” Dunnigan said.
Mike Jess, Nebraska's former top water official, also voiced support for more consideration of conjunctive management. But he warned that important details would have to be ironed out.
Water and politics flow side-by-side in Nebraska, and the main players don't always trust each other, Jess said.
“There's been a lot of litigation over who the water belongs to,” he said. “Those sorts of legal issues would certainly have to be worked out before a plan like this would have vitality.”
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