Bureau diverts water to Front Range, Lake Granby may not spill after all
June 29, 2010
Lake Granby now has about a 50-50 chance of spilling, according to Carlos Lora, hydraulic engineer and water scheduler of the Colorado-Big Thompson Project for the U.S. Bureau of Reclamation.
The system is now pumping 350 cubic feet per second (cfs) of water to the East Slope through the Alva B. Adams Tunnel, “trying to use any little pocket of space (in East Slope reservoirs) we have so we don’t have to spill,” Lora said.
To avoid a Granby Reservoir spill, which would mean increased flows running in the stretch of the Colorado River downstream from the dam project, the Bureau, working with the Northern Water Conservancy District, is diverting water to store wherever available until later this week, at which time it may cut back, depending on the continuance of warm weather and the volume of public need on the Front Range.
In the meantime, the agencies may raise the Granby spill gate one-tenth of a foot so that the elevation that triggers a spill is 8,279.80 rather than the protocol standard of 8,279.50, Lora said.
The reason, he said, is to not lose “project water” for the “benefit of the public in Colorado.”
If the spill does occur, “it will probably be very little,” Lora said. “It’s not going to affect anyone downstream; all the runoff is dying off.”
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Even though the reservoir is not a intended to be a “flood-control” project, “it helps,” he said.
Colorado Division of Wildlife biologists have said a limited spill would benefit the aquatic ecosystem in the stretch of river between Lake Granby and the Fraser River.