CASPER, Wyo. — The North Platte River is one of the most tightly harnessed streams in the West.
Saddled with a series of dams, the North Platte provides irrigation water from central Wyoming to central Nebraska from more than 2,000 miles of canals and ditches.
“It’s complicated plumbing,’’ said John Lawson, U.S. Bureau of Reclamation engineer in charge of federal dams on the North Platte.
It’s also vital plumbing to western Nebraska’s Lake McConaughy, the largest reservoir on the river.
North Platte water — whether it’s trickling runoff from irrigated cropland along the old Oregon Trail or flood flows from melting snow in the Rocky Mountains — is the lifeblood of Lake McConaughy.
Born in the Rockies, the North Platte tumbles northward from Colorado and flows through dams in central Wyoming’s mountain valleys and granite canyons. Then it arcs southeasterly into Nebraska, passes through McConaughy, joins the South Platte and creates the Platte River.
Lawson regulates the North Platte’s flow by raising or lowering reservoir levels. The keystone of the system is 100-year-old Pathfinder Dam.
Completed in 1909, Pathfinder was one of the first dams built under a mandate by President Theodore Roosevelt to reclaim the arid and semi-arid West with farmland irrigated by water stored in mountain reservoirs. Farmers in Nebraska’s North Platte valley were among the first beneficiaries of reclamation water.
Like McConaughy, Pathfinder and other Wyoming reservoirs sustained big drought declines during the past decade. But better mountain snowpacks started to replenish the reservoirs in recent years.
Lawson has a hunch that more water could be heading out of the Rockies and into McConaughy next year.
“This has been such an unusually cool year that if we go into fall cool and wet, it could be an indicator that we may have a fairly good year coming up,’’ he said. “But we’ve had two unusually strong snowpack years, and history says the next year drops off. So who knows?”
Still, Lawson wants to avoid the nightmare of 1983 in which late spring rainstorms hit a big snowpack, creating historic runoff that caught the bureau with too much water in its reservoirs. Floodwater surged down the North Platte into western Nebraska. Then the Rockies had another big snowpack in 1984.
Lawson is hedging his bets by filling Pathfinder with more water than usual this fall, lowering upstream Seminoe Reservoir in preparation for a big snowmelt next spring.
The Central Nebraska Public Power and Irrigation District, the owner of McConaughy, hopes a big snowpack this winter forces Lawson to evacuate water from the Wyoming reservoirs to flow directly to Nebraska and refill McConaughy.
“I wouldn’t mind doing that as long as it’s not a repeat of 1983 and ’84,’’ Lawson said. “We are totally dependent on snowpack.’’
Contact the writer:
444-1127, david.hendee@owh.com
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