Reservoir operators in North Platte River Basin brace for avalanche of water

2011-04-10T08:00:00Z 2011-04-13T18:16:58Z Reservoir operators in North Platte River Basin brace for avalanche of waterBy ALGIS J. LAUKAITIS / Lincoln Journal Star JournalStar.com

It's rare to see millions of gallons of water spilling out of a reservoir, especially in the West, where water is more precious than gold.

But the water was spilling from Pathfinder Reservoir, 45 miles southwest of Casper, Wyo., in June, because it couldn't hold any more water.

The last time that happened was in 1984.

The U.S. Bureau of Reclamation, which controls nine reservoirs in the North Platte River Basin, predicts it will happen again this summer.

The reason: too much snow in the Rockies. When it melts in late spring and early summer, reservoirs will be bursting at the seams.

"Wyoming is loaded with water. They have a lot of snowpack," said Cory Steinke, civil engineer with the Central Nebraska Public Power and Irrigation District based in Holdrege.

Central began releasing water from Lake McConaughy in early March to make room for anticipated record spring runoff, and the bureau has been doing the same from its reservoirs.

"They're throwing water through the system. They're putting in as much as they can and sending it down to us. They see what's coming, and they are a little scared," Steinke said.

The bureau's Wyoming office estimates the snowpack in the upper North Platte River Basin above Seminoe Reservoir is 140 percent of its annual average and will reach 200 percent by early summer.

Projections for runoff through July exceed 1.4 million acre feet of water, double the 30-year average of 714,000 acre feet. Last year's runoff was 1.2 million acre feet.

The bureau recently told Central officials that inflows into Wyoming reservoirs this year will likely rank among the top five highest on record.

"We are trying to evacuate as much water as we can ahead of what looks to be extremely high snowmelt runoff," John Lawson, manager of  the bureau's Wyoming office, said in a news release.

"What we don't know at this time is how quickly the snowmelt will occur, how much more accumulation of snow we'll receive and how much rainfall will occur in the area in addition to the runoff," he said.

Lake McConaughy near Ogallala, which is owned and operated by Central, is independent of the bureau's North Platte Project, a series of storage and diversion dams and canals that provide water for irrigation and hydroelectric power generation mostly in Wyoming.

As of Friday, Lake McConaughy was 93 percent full. A year ago it was 74 percent.

"We may approach 100 percent of capacity (this year)," Steinke said.

Water releases from Lake McConaughy into the North Platte River already have caused some lowland flooding downstream around North Platte. The river has raised the water table, and water is seeping up through the sandy soil.

"Most of it (the flooding) is between the river and North River Road. Some residents live around there," said Jim Nitz, director of Lincoln County Emergency Management. "Their sump pumps are pretty much working full-time."

Due to the high volume of water coming down the North Platte River, the National Weather Service has issued flood warnings for Keith, Garden and Lincoln counties.

Central is working with Nitz and the weather service to keep track of the situation, so if a major storm is in the forecast, water releases can be curtailed from Lake McConaughy.

Steinke said lowland flooding problems could persist through July.

"We're kind of pushing as hard as we can without causing major damage," he said.

Big rains are a worry. A July 2002 flood, caused by 10 inches of rain in five hours, destroyed 64 homes in Ogallala, killed a truck driver and closed Interstate 80 for a week after two bridges collapsed.

Nitz said some families along North River Road may have to be evacuated if the situation gets any worse.

"If we would get heavy rains, that would be a big issue," Nitz said, adding that the North Platte River is running just a little above its flood stage of 6 feet. "We're hoping it doesn't get any higher."

Jan Bush, who lives along North River Road, said water is seeping up through some of the old river channels and flooding some basements and cellars. But her home is not in danger, she said.

"It's been way worse than this. There have been times when there has been water running in ditches on both sides of the road."

Bush said she is more concerned about Lake McConaughy being full and huge waves, pushed by strong winds, causing damage to the face of Kingsley Dam.

The Federal Energy Regulatory Commission, which licenses Kingsley Dam because of its hydroelectric plant, restricts Lake McConaughy's elevation to reduce such wave damage.

Steinke said the lake's elevation is fewer than 5 feet from the maximum water storage level of 3,265 feet permitted by the commission. Central has petitioned the commission for permission to temporarily exceed that by 2 feet.

Central officials also are watching the South Platte River, which funnels spring runoff from the mountains into Nebraska just below North Platte. Steinke said that could create flooding problems in June.

Last year, the South Platte River was flowing at 7,000 cubic feet per second at the Nebraska/Colorado state line, Steinke said. 

The Nebraska Public Power District has two reservoirs downstream from North Platte, Steinke said, but they are typically full and any spare room would be used to capture South Platte River flows.

The avalanche of water, which is creating headaches for water managers, is good news for hydroelectric power generation and for irrigators.

Central customers will get their full allocation of water this year, just like last year, Steinke said.

Between 2004 and 2009, their allocations were drastically reduced because of a prolonged drought.

In September 2004, Lake McConaughy was at less than 20 percent of water storage capacity, its lowest level since it was built in the 1940s.

Reach Algis J. Laukaitis at 402-473-7243 or alaukaitis@journalstar.com.

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