River flows exceed predictions
Delta Independent news article 06/09/11
River flows exceed predictions
Written by Hank Lohmeyer
Wednesday, 08 June 2011 00:00
Photo by Hank Lohmeyer
Gunnison River flows had reached their predicted 13,000 cfs peak on Tuesday morning when this photo was taken, and flows were expected to go higher. Based on the most current conditions Tuesday, a peak flow of 14,090 cfs was forecast for the day. Minor flooding in low areas was occurring.Gunnison River flows of 13,000 cfs (cubic feet per second) predicted at Delta midweek had already reached that level by Tuesday morning and were expected to continue rising. Minor flooding of low lying areas was already occurring.
"We are getting more inflow from tributaries, probably the Smith Fork," said Dan Crabtree of the Bureau of Reclamation in Grand Junction.
Crabtree said that Tuesday would likely see flows of 14,090 cfs at Delta, based on forecasting from the Colorado Basin Forecast Center.
The unexpected extra water comes just as the huge high country snowpack turns to runoff, and as releases from the Aspinall Unit are reaching their peak levels of the year.
BuRec has been planning to operate the Aspinall Unit (Blue Mesa, Morrow Point, and Crystal reservoirs) to allow the one day, Black Canyon water right peak flow of 6,800 to 6,900 cfs to be met this week. Those flows are measured below the Gunnison Tunnel.
Other local streams are being affected also. Late last week, there was deep snowpack holding over two feet of water content at Park Reservoir, which flows into the Surface Creek drainage.
On Monday, Bob Hurford, Division 4 water engineer, said, "Surface Creek has been flowing about 300 cfs, and a lot more is coming. That could go to 700 or 800 cfs very quickly."
The North Fork of the Gunnison River has had flows of 4,500 cfs already this year, Hurford said. Average flows this time of year are less than 2,000 cfs, he added.
The Uncompahgre River drainage is like others in the basin. "We expect well above 2,000 cfs flowing into Ridgway Reservoir this year," Hurford said. Ridgway reservoir was standing at almost three-fourths full beginning this week.
"All of the reservoirs in the Gunnison Basin (Taylor Park, Ridgway, Silverjack, Paonia, and Crawford) will fill this year," said BuRec's Crabtree.
Gunnison Basin snowpack levels have averaged 125 percent of average with moisture content readings over 200 percent of average.
This year's mountain snowpack peaked in the first part of May, almost a month later than usual, explain water managers. In addition, the late snow storms carried high moisture content.
Now that warm weather has arrived, deep alpine snow courses are poised to release a lot of water very quickly.
The water abundance is good news for ag producers. "This is the fourth good runoff year in a row," Hurford said. "There will be a very good water supply for irrigation."
Releases from Crystal Reservoir began ramping up beginning June 3 from the release levels of 3,500 cfs.
Crystal Reservoir was expected to begin spilling Saturday, June 4. While spilling, natural fluctuations are expected on the river system, making it difficult to predict and control downstream flows, said a statement from BuRec.
"Estimated flows in the Black Canyon and Gunnison Gorge below the Gunnison Tunnel should reach a peak of about 6,800 cfs on Wednesday, June 8, and return to about 3,200 cfs around June 13," the statement said.