NO Water for BIG MAC

Post date: May 07, 2013 6:14:41 PM

CNPPID: Recent mountain snow won’t fill Big Mac

Posted: Tuesday, May 7, 2013 12:45 pm By LORI POTTER Hub Staff Writer | 0 comments

HOLDREGE — Central Nebraska Public Power and Irrigation District engineers seem tired of answering questions about when Lake McConaughy will be rising with the runoff from recent snows in the Rocky Mountains.

The simple answer, according to Civil Engineer Cory Steinke and Natural Resources Manager Mike Drain, is there will be no 2013 runoff from the North Platte Basin for Lake McConaughy. Steinke said the lake currently holds 1,091,000 acre-feet of water, which is 63 percent of full. “We’re pretty much done rising,” he told the CNPPID Board of Directors Monday. “I believe we’re gonna stay steady at this point.” Snowpack in the mountains of northern Colorado and southern Wyoming has improved in recent weeks, but drought-depleted federal reservoirs in Wyoming have more than enough room to hold all the snowmelt runoff. Also, upstream irrigation districts have allocations this year, which will harm return flows into the North Platte River. “We live on return flows” from those other districts, Steinke said, not direct runoff into the North Platte River.

“It (snowpack) is not everything it’s cracked up to be,” he said. Even with 90 percent-plus snowpack now above the Seminoe and Glendo reservoirs, the runoff expected to benefit CNPPID is forecast at 55 percent of normal. Steinke said only something “crazy,” such as a big rain in the right place during growing season, would produce a “spill” from an upstream reservoir or extra return flows that would benefit Lake McConaughy.

Federal Bureau of Reclamation officials predict that the two largest Wyoming reservoirs, Seminoe and Pathfinder, will peak at 40 feet and 55 feet below full, respectively, during the irrigation season.

Another challenge in getting Nebraska Panhandle irrigation districts’ return flows to Lake McConaughy is the growing use of groundwater hydrologically connected to the river in between, Steinke said.

“Snow does not produce water in Lake McConaughy in the year it occurs,” Drain said. He explained that what’s needed are several years of big snowpacks that create enough runoff to fill the upstream reservoirs and allow full allocations to the upstream irrigation districts to produce return flows for Lake McConaughy.

Steinke said the best hope for Nebraska this year is flows on the South Platte River from Colorado. “But you never know about the South Platte,” he said.

The snowpack now is 109 percent of normal. Steinke said it’s too early to know if Nebraska will see runoff benefits this year, which depend on having more water than required for the upstream diversions.

Maintaining the mound

Concerns also were raised by board members and Central Water Users leaders about maintaining the groundwater mound under CNPPID-irrigated lands in Gosper, Phelps and Kearney counties.

Irrigation Division Manager Dave Ford reported on spring readings from 141 monitoring wells across the district that give a snapshot of the mound’s ups and downs.

In spring 2012-to-spring 2013 comparisons, half the wells showed an average decline of 1.35 feet and an additional one-third averaged about 4 feet of decline. Those results were expected, Ford said, given that 2012 was the driest growing season year since CNPPID started keeping such records in 1957. He also showed maps comparing 2013 readings to 2003 and also to the baseline average from 1981-1985. There were gains and losses in both comparisons. However, the biggest group of wells — about half in both cases — showed declines of 1½ to 2½ feet.

Ford said that while there are concerns for specific areas, conservations measures explain much of the overall downward trend. No-till farming, the huge growth in pivot irrigation systems, pipelines replacing ditches and lining canals all have contributed to less seepage and groundwater recharge.

Having less water coming into Lake McConaughy also is a factor, said board member Scott Olson of Minden, creating the need for allocations and resulting in less surface water being delivered to irrigated acres over several years. Director William Knoerzer of Elwood said that even with normal water supplies, he thinks the mound is trending down.

“It think it’s true that the mound has peaked in some areas and is spreading out,” said Tri-Basin Natural Resources District General Manager John Thorburn. His district also is collecting data on spring groundwater levels for the three counties, which will be shared with and compared to the CNPPID numbers. “We’ve already capped that thing out,” Director Robert Garrett of Minden said about the mound, because of the conservation measures now in place. He believes the overall numbers eventually will dip below the 1985 baseline.

Water Users wrap-up

Earlier Monday, Central Water Users President Dave Dahlgren of Holdrege made some wrap-up comments from the CWU annual meeting in March.

He referred to a proposal from the Twin Platte and Central Platte NRDs to repurpose the CNPPID canals from irrigation to groundwater recharge that would allow all current surface water users to switch entirely to groundwater irrigation. Dahlgren asked the CNPPID directors to do whatever they can to “protect the mound and our water rights.”

“I think people see us as an easy target” to solve some of Nebraska’s water issues, he said, while questioning whether the yield from the mound under the NRDs’ proposal would provide a sustainable irrigation supply. “It isn’t a panacea for the state of Nebraska,” Dahlgren added.

He asked the board to keep lines of communication open with the water users as the CNPPID staff continues to study the NRDs’ proposal.