Silverthorne: 22nd annual State of the River recap

May 11, 2015
Colorado River Basin in Colorado via the Colorado Geological Survey

Colorado River Basin in Colorado via the Colorado Geological Survey

From the Summit Daily News (Ali Langley):

Summit’s Blue River Basin recorded snowpack near the 30-year average, and the six speakers at the 22nd annual State of the River meeting on Tuesday, May 5, stressed that local residents should feel fortunate that the headwaters community was spared the immediate water supply problems others are facing around the West.

“Everybody has Blue River envy,” said Eric Kuhn, general manager of the Colorado River District. “You’re the sweet spot this summer.”

However, the event’s speakers also emphasized the coming impacts of long-term drought and overconsumption on Summit and other communities that supply the majority of the West’s water.

Kuhn said major water players including Denver Water, which owns and operates Dillon Reservoir, are for the first time loudly prioritizing certainty of water supplies over development because they are worried about their future abilities to deliver water to their current customers…

County Open Space director Brian Lorch and Blue River Watershed Group board treasurer Jim Shaw said restoration projects on the Swan River northeast of Breckenridge and the Tenmile Creek east of Copper Mountain are moving forward with success.

Summit County water commissioner Troy Wineland said Summit’s snowpack didn’t quite reach average this winter, according to data from the Blue River Basin’s four SNOTEL measuring sites. Half of the snowpack arrived in November and December, and it was gone at lower and middle elevations by the end of March, which was unusually dry and warm.

Runoff started sooner this year, and Tenmile Creek flows in early April were five times greater than average, Wineland said. He predicted peak runoff will occur in early June depending on the weather.

On Monday, May 4, Wineland said Old Dillon Reservoir achieved its first complete fill of 303 acre feet. The reservoir is jointly operated by the county and the towns of Silverthorne and Dillon, and it was stocked with golden trout from California that Wineland said should mean good fishing in the next year or two.

Wineland stressed the role that Summit residents can play in shaping the state’s first-ever water plan, which will outline Colorado’s water policy priorities for the next 50 years and will be handed to the governor in December…

Bob Steger, water resources engineer with Denver Water, said his calculations of Summit snowpack included data from Fremont Pass, which is why he measured Summit’s snowpack as above average but “nowhere near the snowpack that we had last year.”

The Blue River Basin may be the only basin in the state that peaks above average, and Denver Water’s No. 1 priority of filling Dillon Reservoir “should be no problem,” he said. “We’re only two feet from full right now.”

It should be a great summer for boating as well as rafting and kayaking below the dam, Steger said. “The fishing will eventually be good, but if you don’t like high water you probably better stay out until sometime in July.”

He answered a question about Antero Reservoir in Park County, which Denver Water will empty this summer ahead of repairs to the 100-year-old dam. The phase that requires draining the reservoir should be done by the end of 2015 with refilling beginning next spring. Steger also said Denver Water is still working on a permit to enlarge Gross Reservoir in Boulder County.

Ron Thomasson, a hydrologist with the U.S. Bureau of Reclamation who oversees Green Mountain Reservoir operations, said runoff flows won’t be high enough this year to allow coordinated reservoir operations that would protect endangered fish on the Colorado River.

Peak flows must be between 12,900 cfs and 23,000 cfs to do that, and the current forecast is for 9,600 cfs, he said…

Kuhn presented last and detailed continued threats facing Lake Powell and Lake Mead operations.

“We’re going to have to cut back our uses,” he said, “after 100 years of develop more, develop more, develop more.”

Lake Mead could likely see its first shortage next year or in 2017, he said, and “bad things happen when Lake Mead and Lake Powell get drained.”

Allowing Lake Powell’s water level to fall below the amount needed to generate electricity would lead to dramatically higher utility bills costs, the elimination of funding for the important environmental programs funded by the hydropower revenue noted above that protect current and future water use in Colorado.

If Colorado and the other Upper Basin states violate the 1922 Colorado River Compact and fail to provide enough water to Lower Basin states, the West could be fighting over water in lengthy court battles and Colorado could be forced to prohibit some water uses.

Western states could lose control of water to the federal government, Kuhn said, and Colorado would likely lose power in management of the Colorado River and water in the state.

When asked about building an interstate water pipeline to solve some shortages, Kuhn said water managers have discussed pipelines of absurd lengths and he doesn’t think that method will work.

“To expect that we can export our problems to somebody else, I just don’t see that somebody else will willingly accept them,” he said.


#ColoradoRiver: “When do we say no, and who do we say no to?” — Mark Squillace

April 6, 2015
Colorado River Basin including out of basin demands -- Graphic/USBR

Colorado River Basin including out of basin demands — Graphic/USBR

From the Mountain Town News (Allen Best):

By its natural flow, the Colorado River originates in Rocky Mountain National Park and ends in the Sea of Cortez. But flows of the Colorado decades ago ceased to be natural, as Phil Fradkin famously captured in his 1981 book “A River No More.”

A discussion on April 3 sponsored by the University of Colorado Law School’s Environmental Law Society examined two aspects of the unnatural flows. All three speakers, in different ways, talked about different management regimes for water revolving around the adage of “just add water.”

Since 1999, Jennifer Pitt has shepherded efforts on behalf of the Environmental Defense Fund to restore flows to the river’s delta in Mexico. Water has not reached the sea with regularity since the 1960s and, until special releases last spring, not at all since the late 1990s.

Eric Wilkinson talked about the diversions of the river and its tributaries to cities along the Front Range of Colorado and to benefitting farms at least as far downstream as the Nebraska and Kansas borders. He’s general manager of the Northern Colorado Water Conservation District, which administers the single largest diversion across the Continental Divide, the Colorado-Big Thompson Project.

Introducing the session, law professor Mark Squillace framed the primary issue of the Colorado as one of management that recognizes inherent limits and demands choices: “When do we say no, and who do we say no to?”

The two giant reservoirs on the Colorado, Powell and Mead, together were at 94 percent of capacity in 1999. By 2007, that storage had dropped to 54 percent of capacity.

This year looks even worse: 42 percent of storage capacity for the two reservoirs, and more decline as the year progresses look inevitable. The National Oceanic and Atmospheric Administration this year projected runoff in the Colorado River to be just 52 percent of normal. “Things are not looking good,” Squillace said.

“Are we facing a crisis?” he asked rhetorically, before answering his own question: “I would suggest it’s not a water crisis. It’s a management crisis.”

In talking about the successful effort to return water to the river delta in Mexico during March 2014, Pitt described a long, evolving process that essentially began in 1999 with a study that found that ecosystem functions in the river delta could be restored with just 1 percent of annual flows. Securing that water for a successful pulse of water last year required persistence and new levels of cooperation.

Wilkinson continued Pitt’s theme. “Everything you do with water takes time,” he said.

The Colorado-Big Thompson Project itself took time. It was conceived in at least some vague ways in the late 1890s as farmers in the South Platte Valley of northern Colorado noted insufficient water for late-summer irrigation. Recurrence of drought in the 1930s added argument for a giant, federally funded capital works project. Work began in 1938 on Green Mountain Reservoir, to serve needs of the Western Slope, but final work was not completed until 1957.

This and other diversions from the Colorado River headwaters have created a thriving economy along the Front Range. Weld County, the largest in the basin, is 8th in the nation in total agricultural production. By itself, Weld County produces more than all 20 counties on Colorado’s Western Slope combined.

All this belies the impression of Zebulon Pike who, upon encountering the high plains leading up to the Rockies, made comparisons to the deserts of Africa. “Just add water,” Wilkinson advised. He said that two-thirds of irrigated acres in Colorado get at least some of their water from the Colorado River.

The munificence of Colorado River water extends to the cities of the Front Range corridor, where about 85 percent of Coloradans live, mostly in the fast-urbanizing strip along I-25 north from Denver. The Front Range, said Wilkinson, represents 80 to 86 percent of Colorado’s economic activity.

Wilkinson’s description of Colorado’s transmountain infrastructure was a story of triumph. The future, he acknowledged, is far more muddled.

One outstanding issue is whether Colorado can expect to divert substantial amounts of additional water from the Colorado River and its tributaries. It’s not clear how much Colorado has left of its apportionments as specified by two major compacts governing the Colorado River, the seven-state compact of 1922 or the 1948 compact among the four headwaters states.

But even if there is water, said Wilkinson, there are additional questions: “If so, how do you develop it, and if so, how do you develop it in ways that protect basins of origin and still make the project economical?”

Then there’s this simple fact: existing diversions are not an absolute. They depend upon volumes of water in the river to meet compact requirements—and deepening drought could throw even long-standing diversions off the rail.

Responding to a question about California’s drought, Wilkinson said that he is “scared” that the federal government—administrator of the compact—will someday force curtailment of diversions with appropriation dates after 1922. That would include the Colorado-Big Thompson.

As the northern Front Range looks to add 2.5 million people during the next 35 years, the equivalent of the existing Denver-Boulder metroplex, there will be questions of where the water will come from. There is, said Wilkinson, a “disconnect” between the people who provide water and the people who approve residential developments.”

All this points to a new era of water management, as opposed to the “just add water” mantra of the mid-20th century.


The water czar who reshaped Colorado River politics — High Country News #ColoradoRiver

March 9, 2015

Pat Mulroy via The Earth Institute at Columbia University

Pat Mulroy via The Earth Institute at Columbia University


Here’s an in-depth look at Pat Mulroy and her role shaping Colorado River politics and leading the Southern Nevada Water Authority into the 21st Century, from Matt Jenkins writing for the High Country News. Click through and read the whole article. Here’s an excerpt:

In 1985, Mulroy became deputy general manager of the Las Vegas Valley Water District, one of seven water agencies that supply Vegas and its suburbs. By 1989, she was general manager — and found herself with a fight on her hands. The seven agencies were running out of water and squabbling over what remained. “Southern Nevada was in meltdown,” she says. “It was acrimonious and ugly.”

It took three years to find “peace and a pathway forward,” as she puts it, by convincing the other agencies to cooperate under the banner of a new superagency called the Southern Nevada Water Authority, whose primary goal would be to ensure water supplies for the entire metropolitan area. From the start, it was clear that Mulroy would be in charge. “There was no way in hell,” says George Forbes, then Boulder City manager, “that she was going to play Number Two to anybody.”

Then Mulroy turned outward. In the 1920s, when the Colorado River was originally divvied up, Las Vegas was little more than a railroad stop, and Nevada was a sparsely populated desert. The other six states that share the river received nearly all the water — and the power. Mulroy was determined to change that by challenging the so-called “law of the river,” an amalgamation of more than four-dozen statutes, international treaties and court decrees that other states’ managers adhered to, Mulroy notes sarcastically, as if they were Moses’ tablets. With southern Nevada’s warring agencies now united, Mulroy was ready to take on the other states. “When we said something,” she says, “they knew we meant it.”

For his part, Bunker likens Mulroy’s entrance into the broader realm of Colorado River politics to unleashing “a flash-bang grenade” on a bunch of “old, mossback, gray-headed guys.”

Mulroy’s grand entrance came at a critical time for Las Vegas, which was well on its way into a major boom. In 1992, when Mulroy took charge of the Water Authority, roughly 840,000 people lived in the metropolitan area. Over the next decade, that number would nearly double. By 2002, Mulroy fully expected to have hit the limits of Nevada’s full Colorado River allocation of 300,000 acre-feet — roughly 98 billion gallons per year — even as the city continued to swell.

So she launched a campaign to wrest more water from the Colorado. Roughly 70 percent of the river’s water is used for agriculture, and many urban water agencies see that as a reservoir on which they might draw if necessary. But there’s very little farming in southern Nevada, so Mulroy was forced to look toward other states. This was sacrilege in a system where each state traditionally guarded its own allocation of the river as if it was more precious than gold.

Her sights eventually fell on Chevron, which held rights to water that it hoped to use to extract oil shale in western Colorado. The company needed a way to put the water to use until the shale industry took off. One way to do that might be by leasing it to Las Vegas.

That, however, would run headlong into a hallowed proscription in the state of Colorado. Owing to the structure of the law of the river, the upstream, Upper Basin states — Colorado, Wyoming, Utah and New Mexico — and their downstream, Lower Basin counterparts — Nevada, Arizona and California — form two separate negotiating blocs, which are set squarely in opposition to each other on key legal controversies. And Colorado officials have long maintained that, under the law of the river, transfers between the Upper and Lower basins are illegal.

Though it would be decades before Colorado needed its full river allocation, officials there saw Chevron’s water as critical to the state’s future economic development. If Las Vegas came to depend on the water, they feared, Colorado might lose its rights through a sort of adverse possession.

So when Jim Lochhead, a strategy advisor for Colorado, heard about Mulroy’s negotiations with Chevron, he quickly booked a flight to Vegas and delivered a warning: Back off. “She would have gotten years and years of litigation,” Lochhead said last year. “And she wouldn’t have gotten any water.”

Mulroy turned her attention to the safer territory of the Lower Basin. Water managers there were already bandying about a series of interstate “banking” proposals, under which the states could store water for each others’ use. Both Arizona and California were interested, but Nevada’s need was urgent.

Finally, in 2001, Mulroy got what she wanted: The Southern Nevada Water Authority inked a deal under which it would pay a counterpart in Arizona to buy water from farms there and store it underground. In return, the Water Authority could, in later years, take an equivalent portion of Arizona’s share of the Colorado River directly from Lake Mead, the massive reservoir just east of Las Vegas from which the city already draws most of its water.

Though it was pitched as a banking deal, it was really an exercise in figuring out how to move water across state lines. “If you think about it, it’s pretty much the exact same thing as us going to Arizona and buying water and moving it to Nevada,” says David Donnelly, who was Mulroy’s engineering and operations chief and the principal architect of this deal. “Except in this case, Arizona buys it, takes the water and banks it for us — and then we get it back in the future.”

It was also the first federally sanctioned deal for a water transfer between two states. But Mulroy has only ever spoken about it euphemistically because transfers, even within the Lower Basin, are so politically charged. “Don’t ever call it a transfer,” she scolded during a 2008 interview. “It’s a banking agreement. That thing will disappear on us tomorrow if we call it a transfer.”

She had learned a crucial lesson, however. In the years that followed, Mulroy would — despite her reputation as a woman who didn’t mince words — speak an increasingly convoluted lingua franca that would eventually include enigmas like “intentionally created unused apportionment.” It sounds like gobbledygook, but it was all for a larger end.

“I learned it’s not what you do, it’s what you call it,” Mulroy told me. “You find the right name for it, and you can do anything.”

The opaque language bought managers leeway to try new approaches within the arcane system of interstate water management on the river. That helped Mulroy in her quest for water to sustain Vegas’ runaway growth. Ultimately, however, it would help all the Colorado River water bosses weather a much bigger looming disaster.

More Colorado River coverage here.


Transparency and the Colorado River Compact — John Fleck #ColoradoRiver

January 18, 2015
Members of the Colorado River Commission

Members of the Colorado River Commission

Click through to read John Fleck’s reflection on the minutes from the negotiations for the Colorado River Compact on InkStain. Here’s an excerpt:

The negotiation of the 1922 Colorado River Compact governing the allocation of water from the West’s great river, and the ratification process that followed, was a politically delicate process.

Precisely how delicate is made clear in a fascinating exchange of letters 10 years after between Colorado attorney Delph Carpenter (the compact’s primary architect) and Norcutt Ely, who at the time was executive assistant to Interior Secretary Ray Lyman Wilbur.

The Compact Commission’s 27 sessions were largely closed affairs, though detailed minutes were kept…

…they were stashed in a “small room” at the Commerce Department. Carpenter suggests several people who might know where they were, and that they be forwarded to the state representatives “before they become lost”.

Thankfully, they were not lost. The University of Colorado has published them in full.

I found the Carpenter-Ely letters in the Colorado State University digital collection.

More Colorado River Basin coverage here and here.


Water Lines: Colorado Water Plan delivered, key dilemmas remain — Hannah Holm

December 27, 2014

From the Grand Junction Free Press (Hannah Holm):

Colorado lurched one more step towards resolving how to satisfy growing demands for water with stable-to-diminishing supplies when Governor Hickenlooper received the first complete draft of a statewide water plan on Dec. 10.

In compiling the plan, the Colorado Water Conservation Board (CWCB) provided the latest information on current and projected water supplies and defined some “no regrets” actions that would help no matter what the future holds. These include achieving at least low-to-medium levels of conservation, completing already planned projects, implementing water re-use projects, and preserving the option of taking more water out of the Colorado River and its tributaries to meet both West and East Slope needs.

The CWCB stopped short of endorsing (or vetoing) any particular projects to meet future needs or taking a hard stand on the role conservation and land-use restrictions should play in meeting future needs. The draft plan maps the landscape, but doesn’t define the route.

The identification of specific projects was left to roundtables of water providers and stakeholders in each of the state’s major river basins. As anticipated, those basin plans conflict on the issue of whether East Slope basins can continue to rely on additional West Slope water to meet their growing needs. Approximately 500,000 acre-feet per year already flows east across the Continental Divide through ditches and tunnels that siphon off a majority of the natural flows from many headwaters streams. One acre-foot can meet the needs of two to three households for a year under current usage rates.

Seven-point draft conceptual agreement framework for negotiations on a future transmountain diversion screen shot December 18, 2014 via Aspen Journalism

Seven-point draft conceptual agreement framework for negotiations on a future transmountain diversion screen shot December 18, 2014 via Aspen Journalism

While the draft plan doesn’t say “yes” or “no” to additional transmountain diversions, it does incorporate a seven-point “draft conceptual agreement” on how to negotiate on future transmountain diversions. The draft discussion framework (there’s been a lot of push back on calling it an agreement) contains several new features in the many-decades-long debate between East and West Slope actors over transmountain diversions. It states that the East Slope is not looking for stable water deliveries each year from any such project, recognizing that it may only be able to divert in wet years and would have to use transmountain water in conjunction with non-West Slope sources, such as the Denver Basin aquifer and temporary transfers from agriculture.

The draft framework also notes the need for an “insurance policy” to protect against Colorado water users getting cut off in the event that we fail to let enough water flow beyond the state line to meet downstream obligations. Colorado and the other Upper Colorado River Basin states have never failed to meet their obligation to downstream states under the 1922 Colorado River Compact, but the margin by which we’ve exceeded it keeps diminishing. Additional use in Colorado, Utah, Wyoming and New Mexico, plus continued drought, could push us over that threshold.

While the draft framework is a tiny part of the draft Colorado Water Plan, it’s likely to be at the center of debate between water leaders from each of the state’s major river basins as the draft Colorado Water Plan becomes “final” over the coming year. In a meeting Dec. 18, members of the four West Slope basin roundtables met in Grand Junction to work towards a common negotiating position in those discussions.

The four roundtables share extreme skepticism about the wisdom of any transmountain diversion, no matter the caveats; they also share a concern that any “insurance policy” to protect existing uses from curtailment under the 1922 Colorado River Compact would ultimately result in water being transferred out of West Slope agriculture, even if the transfer is voluntary and lower-impact than the wholesale “buying and drying” of agricultural water rights that has already devastated some East Slope farming communities.

Where the West Slope roundtables begin to diverge is over how additional Colorado River Basin development on the West Slope figures into the picture. Given that any new uses raise the risk of failing to meet downstream obligations, should new West Slope water projects be looked on any more favorably than new projects to send water across the Continental Divide? Where is the right line in the trade-off between protecting existing Colorado River water users and making the fullest use possible of the resource? And what place should “nonconsumptive” uses of water for the health of the environment and recreation play into these decisions?

This already complicated dilemma is made more complicated by the fact that the Yampa and White river basins have fewer dams and diversions on their streams than the other West Slope river basins, and therefore have a greater interest in new projects to provide greater security for existing users, as well potentially irrigate even more land and/or meet the needs of increasing energy development. Is the Yampa Basin bearing an unfair share of the burden of meeting downstream obligations, or would it be even more unfair for existing users in other basins to have to cut back in order to subsidize Yampa Basin growth?

In the quest to find common ground on this issue, participants in the Dec. 18 meeting called for better hydrologic data in order to better understand how much additional risk is created by different levels of additional use.

I don’t know if that’s possible, given the current state of scientific understanding of our region’s climate and hydrology, particularly when it comes to forecasting. What may bear fruit is the search for the right “triggers,” in terms of reservoir and/or streamflow levels, to indicate when more development, on either side of the Continental Divide, can proceed without posing unacceptable risks to the whole system. Don’t expect this dilemma to be resolved any time soon, no matter what deadlines exist on paper.

This is part of a series of articles coordinated by the Water Center at Colorado Mesa University in cooperation with the Colorado and Gunnison Basin Roundtables to raise awareness about water needs, uses and policies in our region. To learn more about the basin roundtables and statewide water planning, and to let the roundtables know what you think, go to http://www.coloradomesa.edu/WaterCenter. You can also find the Water Center on Facebook at http://Facebook.com/WaterCenter.CMU or Twitter at http://Twitter.com/WaterCenterCMU.

More Colorado Water Plan coverage here.


Draft conceptual diversion deal presented to West Slope water interests — Aspen Journalism

December 23, 2014
Informational graphic screen shot December 18, 2014 via Aspen Journalism

Informational graphic screen shot December 18, 2014 via Aspen Journalism

From Aspen Journalism (Brent Gardner-Smith):

A draft seven-point framework that lays out conditions for a potential new transmountain diversion in Colorado was explained Thursday in Grand Junction to the members of four Western Slope water-planning roundtables.

About 75 members of the four roundtables heard Bruce Whitehead, a member of the Interbasin Compact Committee, describe in relatively plain terms a “draft conceptual agreement” the committee reached in June on how to possibly move more water from the Western Slope to the Front Range.

“This is conceptual,” said Whitehead, who serves on the Southwest Basin roundtable. “We haven’t sold the ranch, and I don’t think, intend to. It was really to set up a dialogue about, yes, go ahead and say it, transmountain diversions. What are the pros? What are the cons? How do we meet Colorado’s gap in the future?”

Whitehead said the seven-point framework had moved the discussion about a new transmountain diversion past the water-planning euphemism “new supply.”

“The term ‘new supply’ had been used a lot,” Whitehead said. “And folks on the Western Slope, obviously, are a little sensitive about new supply. I’ve heard it stated that it might be new supply to somebody else but it’s not really a new supply.”

Sawyer Creek diversion via Aspen Journalism

Sawyer Creek diversion via Aspen Journalism

The 7-Points, in the draft water plan

The 27-member Interbasin Compact Committee serves as something of an executive committee for the nine basin roundtables. Its mission includes developing new water storage and providing a framework for negotiations between the roundtables.

The Colorado Water Conservation Board, the state agency charged with planning for the state’s water needs, oversees both the committee and the roundtables.

On Dec. 10, the agency presented a draft Colorado water plan to Gov. John Hickenlooper. The plan includes the committee’s seven-point “draft conceptual agreement.”

Whitehead explained that the committee members were polled at a meeting in June using a clicker system, and all of them endorsed the statement, “I agree that the draft conceptual agreement is ready to go the water conservation board for consideration while we continue to get feedback from our roundtables and constituencies and the public.”

“So it is not a done deal,” Whitehead said. “And I know there’s even been some things in the newspaper here recently that agreements have been cut, that a deal’s been done, and that’s not the case.”

Members of both the Colorado River Basin and the Gunnison River Basin roundtables recently expressed dismay that a perception had been created that an agreement on a new transbasin has been reached.

“Our last roundtable meeting in November was a very emotional, heartfelt meeting where we discussed the seven points,” said Louis Meyer, a member of the Colorado roundtable. “We are the donor basin. There are currently 15 major transmountain diversions diverting between 450,000 and 600,000 acre-feet out of our basin.”

At their November meeting, the Colorado roundtable members unanimously adopted a motion stating that “it would be premature and inappropriate” to include the seven points in the Colorado water plan.

“We’re not saying they don’t belong in Colorado’s water plan; we’re saying they are not ready yet,” Meyer said at Thursday’s meeting, which also was attended by another 75 or so members of the public and Colorado’s professional water community. “They need a lot more discussion.”

The first and perhaps most significant of the seven points states that “the eastern slope is not looking for firm yield from a new transmountain diversion project and would accept hydrologic risk for that project.”

“I think the (Interbasin Compact Committee) has acknowledged that in high-water years, and at high levels of storage, there is probably some water left to develop in the Colorado River system,” Whitehead said of the first point. “In very low years, as in the previous 14 or 15 years we’ve just seen, there may not be.”

Whitehead said the third point, concerning “triggers” that might force a new transmountain diversion to divert less water, was about managing a potential “compact call” from California and other lower-basin states. Such a call could force junior water-rights owners in Colorado and other upper-basin states to stop diverting water.

“If it looks like we’re going to be headed toward compact curtailment of some kind, then they shouldn’t divert and increase that risk,” Whitehead said of a new diversion. “What those triggers are hasn’t been fully defined.”

The fourth point calls for an “insurance policy” for existing junior water rights, and raises the question of how much more water should be diverted from the state’s west-flowing rivers in the face of a looming compact call.

“Obviously, any development is going to increase the risk,” Whitehead said. “In my mind, 2 acres of irrigation on the Animas River that has a fairly small depletion is a bit of a different animal than a 100,000 acre-foot diversion. So how do we handle that? Is there a de minimus amount that we could agree to that would allow for some future uses on the Western Slope while trying to minimize that risk?”

Most of the basin roundtables are set to meet in January, and the Interbasin Compact Committee, which has not met since June, is slated to meet Jan. 28. A final version of the Colorado water-supply plan is due in December 2015.

Editor’s note: Aspen Journalism and The Aspen Times are collaborating on coverage of rivers and water. The Times published this story on Monday, Dec. 22, 2014.

More IBCC — basin roundtables coverage here.


Blue Mesa Reservoir water bank study #ColoradoRiver

December 14, 2014

Aspinall Modeling Memo coverviaarkansasbasinroundtable122014
Click here to read the report.

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.


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