Work at Blue Mesa Reservoir to blame for slowdown

The Gunnison River flows over the diversion dam, marking the east portal of the 11-mile Gunnison Tunnel. The tunnel has not been opened for water this year, although water managers say that may happen as early as this week.

Anglers found less water than expected in the Gunnison River this weekend when flows above the Pleasure Park were hanging around 380 cubic feet per second, about half of what was expected.

Blame the shutdown on Blue Mesa Reservoir, or at least on the continuation of work being done on that dam’s power plant.

“Blue Mesa is basically shut down. There’s nothing coming through there,” said Erik Knight, hydrologist for the Bureau of Reclamation’s West Region office in Grand Junction. “Any water (in the Gunnison) is coming out of storage at Morrow Point (Reservoir).”

Knight said the power plant work is expected to be finished by late this week, but that may or may not bring higher flows to the river below the Gunnison Tunnel.

“Once the power plant work is done on Blue Mesa, the releases will start going up,” Knight said. “But we’re not yet sure where the releases will land.”

This is where water management in the West becomes a spiderweb of interlaced demands and probabilities: How much water reaches the Gunnison Gorge below the Gunnison Tunnel depends in part on how soon the Uncompahgre Valley Water Users Association needs water for irrigation.

It’s expected the water users will start looking for irrigation water this week, which means some quick shuffling of resources to fulfill the water requests.

In addition, how much water reaches the lower Gunnison Gorge depends on how soon Ridgway Reservoir comes back online after being closed to allow rescuers to recover the wreckage of a small plane and its passengers.

Parks and Wildlife said Tuesday the park could reopen Thursday.

“There are a bunch of things we have to consider,” Knight said.

If Ridgway can start releasing water, “that might satisfy the water users for the time being,” Knight said, and any Blue Mesa releases will flow down the Gunnison.

However, Knight said if Ridgway stays off line and the water users demand their water, “We’ll have to increase releases from Crystal (Reservoir) to get water into the tunnel.”

How much water is released from Crystal might affect flows downstream on the Gunnison, but the real changes will come when Blue Mesa returns to service.

Knight said flows in the Gunnison Gorge and the river below may return to around 800 cfs, but there are no guarantees when it comes to sharing water.

“I imagine we’ll return to 800 cfs (in the Gunnison) by the weekend, but the other side of that is if the tunnel comes on, that will take some of the water,” Knight said, doing some quick computations. “So the river may not reach 800 (cfs). There are lot of things happening all at once.”


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