Lake's future still cloudy

OGALLALA, Neb. — Lake McConaughy remains a riddle.

Nebraska's largest reservoir and most visited recreation site was last full of water in 1999.

Then came a dry spell deeper than the drought of the Great Depression.

By 2004, the lake had dropped nearly 70 feet and held only 20 percent of its capacity. McConaughy had never been lower since filling in 1949.

Then the reservoir flirted with the historic low again in 2006.

Today, the lake is half full, but its future is as hard to grasp as a fistful of the fine, white sand that rims the reservoir.

“This may be the new reality,'' said Tim Anderson, spokesman for Central Nebraska Public Power and Irrigation District in Holdrege, which owns and operates the reservoir.

If McConaughy shrinks from its Big Mac image into a Baby Mac role, the impact will be felt far from the cornfields its water irrigates in south-central Nebraska.

Covering nearly 48 square miles and, when full, stretching 22 miles behind Kingsley Dam on the North Platte River, McConaughy is not just a source of water for Nebraska's largest irrigation district.

Its water cools the state's largest power plant at Sutherland. It's part of a system that is a source of water for four of Nebraska's five largest cities: Omaha, Lincoln, Grand Island and Kearney.

It provides flows for habitat critical to endangered species. It recharges a sea of underground water that oozes south, helping Nebraska's Republican River water deficit with Kansas.

Besides the big lake created by Kingsley Dam, some of the state's most popular recreation areas rely on Platte River water, including Lake Ogallala, Sutherland Reservoir, Johnson Lake, Two Rivers State Recreation Area and Platte River and Mahoney state parks.

Central started constructing McConaughy in the 1930s in semi-arid western Nebraska under the assumption that 1 million acre-feet of water from the North Platte River would flow into the reservoir every year. That amount of water would cover 1,562 square miles of land 12 inches deep.

Most of it was snowmelt runoff from the mountains of Colorado and Wyoming and excess water applied to cropland by farmers who diverted North Platte water into ditches for irrigation.

McConaughy dipped and rebounded over the years as Central released water in the summer for its downstream irrigators and collected North Platte flows during the rest of the year. But it never experienced decline — not even during a serious drought in the 1950s — like that seen in the past 10 years.

“I never want to see the bottom of the lake here again,” said Albert Van Borkum at Van's Lakeview Fishing Camp on McConaughy's south shore.

At times during this decade of drought, only a shallow stream of water — not a broad, deep reservoir — separated the north and south shores near Van Borkum's camp. Van Borkum set out a portable dock nearly a mile downstream to put in and take out customers' boats. One day he clocked 47 miles back and forth across the sandy former lake bottom to unload and load boats.

“It was a scary time. The reservoir was falling and no one really knew what was out there,” Van Borkum said. “Would it be a big mud flat? Would it be sand? Could we launch boats?”

He moved docks twice a week, following the declining reservoir.

Boaters who wanted easy access to ramps and docks disappeared when the lake was at its lowest. Some are returning with the rebounding lake, Van Borkum said.

Mike Drain, Central's natural resources manager, said McConaughy's future is closely linked to how well state and local water managers address the annual impact of upstream farmers pumping underground water to irrigate cropland in the North Platte valley.

An analysis earlier this year indicated the pumping robs McConaughy of the equivalent of 5 feet of water depth each year, and the total is growing.

“It's not as big as the impact of drought, but those irrigators' straws in the ground are the straws breaking the camel's back,'' Drain said.

Central, which has a state-granted right to water in the North Platte, has unsuccessfully asked the North Platte Natural Resources District to impose strict limits on the amount of water irrigators may pump from the ground. Central contends that less groundwater pumping would boost river flows into McConaughy.

Central, for its part, has trimmed its irrigators' annual allotment of McConaughy water to 6.7 inches or 8.4 inches from a contracted 18 inches for each of the past six years. The water allocation for next summer may be raised to 15 inches, reflecting McConaughy's improved condition.

The district's conservation measures, combined with improved rainfall that diminished the need for irrigation by Central's farmer customers, helped keep McConaughy afloat.

“We were always teetering on the edge of disaster,” Drain said. “There always was the chance that the water we saved for the next season would be the last water in the lake and we'd be dry at the end of that summer.”

Lake levels at the end of the 2007 and 2008 irrigation seasons were up 10 feet from the previous summer. Last week, the lake was 16 feet higher than a year ago.

Assuming inflows improve to average this winter and spring, the lake level could climb 17 feet before next year's irrigation season. That would put McConaughy at 3,246 feet above sea level, an elevation not seen since June 2001.

North Platte flows into McConaughy, however, have been 55 percent to 60 percent of average, a factor of drought and upstream groundwater pumping. The lowest March inflow into the lake from the North Platte — since Kingsley Dam was completed in 1949 — was recorded this year.

“People say the worst is over,” Anderson said. “We don't see it yet.”

Contact the writer:

444-1127, david.hendee@owh.com

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