Blue Mesa Reservoir water bank study #ColoradoRiver

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From The Pueblo Chieftain (Chris Woodka):

Another piece of the Colorado River shortage puzzle has been put in place with the completion of a Blue Mesa Reservoir water bank study. The study was a joint effort by the Arkansas Basin Roundtable, Gunnison Basin Roundtable and Colorado Water Conservation Board. It looked at whether water could be stored in Blue Mesa Reservoir near Gunnison to be released during a drought when Colorado might owe water to downstream states.

“There are benefits to the environment during low-flow periods,” said Mark McCloskey, of CDM-Smith, consultants for the study, as he explained the study to the Arkansas Basin Roundtable this week.

Under the 1922 Colorado River Compact, upper basin states (Colorado, New Mexico, Utah and Wyoming) are required to deliver 75 million acre-feet to Lake Powell under a 10-year rolling average. If that fails to happen, downstream states (Arizona, California and Nevada) could issue a call on the river. Colorado’s share is 51.25 percent of the deficit.

Another 1.5 million acre-feet annually must be delivered to Mexico.

While there has never been a shortfall of deliveries, there are indications from tree-ring studies that decades-long dry spells are possible.

The study used the worst-case scenarios from the Bureau of Reclamation’s Colorado River Basin study — high demand in very dry years — to develop models of optimum timing and levels of storage in a water bank in Blue Mesa. It projected water that would be needed if levels fell to 80-98 percent of minimum levels. The study also determined how much water would be lost to evaporation or to stream banks along the way to Lake Powell.

Replacement water likely would be purchased by Front Range or statewide interests from ranchers, and it’s not known how those purchases would affect high-altitude hay meadows, McCloskey acknowledged.

It’s important to the Front Range, because a call on the Colorado River could mean curtailment of diversions across the Continental Divide.

A curtailment could mean less water for Pueblo, the Fryingpan- Arkansas Project, Colorado Springs, Denver, Aurora and the Colorado-Big Thompson Project.

All of those have water rights that were established after the 1922 compact.

The study showed the optimum time to store water would begin when deliveries fell to 85 million acre-feet in a 10-year period. The optimum amount to keep in storage would be about 300,000 acre-feet. Some benefit was also seen in deficit irrigation below Blue Mesa in dry years to preserve river flows.

The compact was drawn up by the states and approved by Congress because down­stream development was already occurring in Arizona and California. While it was known that drought impacts the basin, most thought the average flows in the 1920s could be used as a yardstick.

The flows at that time actually were higher than they have been in the ensuing decades. Record low flows were recorded during the 2000s.

More Colorado River Basin coverage here.

Arkansas Basin Roundtable meeting recap

Basin roundtable boundaries
Basin roundtable boundaries

From The Pueblo Chieftain (Chris Woodka):

Wildfires can send irritating smoke into the air for days or even weeks, but the damage to water lingers much longer. So the Arkansas Basin Roundtable agreed this week to form a committee that will look at watershed health. Roundtable groups are open to all members who are interested in the topic.

Mark Shea, a Colorado Springs Utilities employee who has spearheaded recovery efforts for the Waldo Canyon and Black Forest fires, will head the committee.

“After the fires of 2012-13, watershed health popped up on everyone’s radar screen,” Shea said. “The reclamation of watersheds in the state has become a huge issue.”

Collaboration, one goal when the basin roundtables were formed in 2005, would have benefits leveraging federal money for watershed health projects.

“The future of competing for federal dollars is going to be dependent on the ability to show that all stakeholders are working together,” said Paul Crespin, ranger for the San Carlos district of the U.S. Forest Service.

Carol Ekarus, director of the Coalition for the Upper South Platte, reinforced that viewpoint. CUSP has stepped to help with efforts to stabilize the Waldo Canyon burn scar and other damage throughout the state.

“There are interests that stretch across an entire watershed,” she said.

The danger from large wildfires to water supplies comes from ashes, sediment and debris washing into reservoirs when rains return after the burn.

The damage was evident after the 2002 Hayman burn and large water suppliers like Denver, Aurora and Colorado Springs were sounding alarms even before the disastrous 2012-13 fire season.

Water providers already are working with the Forest Service and Bureau of Land Management to reduce the danger of fires in watersheds that have not burned as well as recovery in those that have.

More effort is needed.

“This has more to do with forest health,” Crespin said. “We feel the forest is in very poor condition.”

Jeris Danielson, a former state engineer who now runs the Purgatoire Conservancy District, pointedly asked Crespin if water rights issues are involved.

The Forest Service has tried in recent years to insinuate federal water rights in ski area contracts and it’s feared that ranching contracts also could contain such provisions if not checked.

“Water rights issues have to be resolved at the local level,” Crespin said, adding that he is not the Forest Service expert on water rights.

Others on the roundtable enthusiastically supported forming the committee, noting that Shea, who has been working with watershed health issues for the past two years, is the best choice to head it.

“I see it as a bigger umbrella than just fire prevention and restoration,” said Jay Winner, general manager of the Lower Arkansas Valley Water Conservancy District.

“Watershed protection, what more can you do to deal with water quality?” said Reeves Brown, a Beulah rancher.

“This is a good idea,” said Terry Scanga, general manager of the Upper Arkansas Water Conservancy District.

More IBCC — basin roundtables coverage here.