Fixing ‘moving’ dam near Kremmling could cost $15M — Aspen Journalism #ColoradoRiver #COriver

Upstream side of Ritschard Dam, which forms Wolford Reservoir
Upstream side of Ritschard Dam, which forms Wolford Reservoir

From Aspen Journalism (Brent Gardner-Smith):

It could cost $15 million to dig up and recompact the rocks on the downstream side of the dam that creates Wolford Reservoir, north of Kremmling, in order to stop the dam from moving slightly, but steadily.

“It is a pretty significant surgery of the dam,” John Currier, chief engineer at the Colorado River District, told the district board July 22 during a presentation.

Ritschard Dam was built for the river district in 1995 by D.H. Blattner and Sons of Minnesota for $42 million. The dam is 122 feet tall and 1,910 feet wide.

The $15 million estimate to rehabilitate the dam includes a 35 percent contingency factor and is still preliminary, Currier stressed.

The project would include removing the top 25 feet of the dam and then stepping down the downstream face of the dam in layers to get to three “bad acting” zones of poorly compacted rock, some of which are 90 feet inside the dam.

“At some point that movement will compromise the ability of the core of the dam to hold back the water,” Currier said.

Currier said there are “no near-term safety concerns” regarding the dam’s current ability to hold back 66,000 acre-feet of water from Muddy Creek, which flows into the upper Colorado River east of Gore Canyon.

“We’re not in any crisis,” Currier said. “We’re just ready to move this forward.”

Engineers with the district noticed in 2008 that the dam had settled vertically by a foot-and-half instead of just 1 foot, as expected.

The dam has now settled 2 feet, at the rate of about an inch a year. And it has also moved horizontally, by about 8 inches, at a spot 40 to 50 feet below the crest of the dam.

The dam’s impermeable clay core is held in place by rock shells on both the upstream and downstream sides of the dam.

A detail of the rock outer shell on the downstream side of Ritschard Dam
A detail of the rock outer shell on the downstream side of Ritschard Dam

Trouble at some point

The upstream rock shell appears to have settled appropriately in place, perhaps because of varying degrees of water pressure on its face as reservoir levels have fluctuated.

But the downstream shell is still moving.

“At some point that movement will compromise the ability of the core of the dam to hold back the water,” Currier said.

Currier said construction-sequence photos indicate the movement appears to be related to how fill material above and below haul roads was compacted during construction.

The plan is to dig into sections of the shell, remove the poorly compacted rock, and then recompact those zones, mainly using the same rocks.

“The bad-acting layers may be more a function of how the material was placed, not the material itself,” Currier said.

Currier said a consulting engineer at the firm of AECOM had observed that the construction work is essentially “just a big dirt job,” albeit one that will require complicated sequencing and careful on-site supervision by experienced engineers.

Over the last six years staff and consulting engineers have taken a variety of steps to investigate the situation at Ritschard Dam.

A graphic of the issues at Ritschard Dam from the Colorado River District
A graphic of the issues at Ritschard Dam from the Colorado River District

$1.5 million spent

They’ve installed inclinometers, established an expert review panel, developed modeling and conducted lab tests on the core material to establish that the dam did not present an immediate safety problem.

The river district has now spent close to $1.5 million on instrumentation and analysis, Currier said, and recent work on a range of alternatives has given engineers enough information to move from the “what” stage to the “how” stage.

“We have a very good understanding of what solutions might, or might not work, and thus we can we have a great deal more confidence in our solution,” Currier said. “We’re confident that structural rehab is required.”

Currier said that simply storing less water in order to take pressure off the dam won’t solve the long-term problem.

In a memo to the board, Currier wrote “operating at reduced levels slows the deformation rate but does not stop the deformation.”

The river district has been operating the reservoir at 10 feet below normal levels since 2014 as a standard precautionary measure.

Another option looked at was installing a series of concrete columns down through the downstream shell of the dam in order to stiffen it, but Currier said it was ruled out due to higher costs and doubts about its effectiveness.

There is also the opportunity to increase the amount of water the reservoir can hold by increasing the height of the existing spillway, but Currier advised it was better to first just fix the dam to avoid a “permitting quagmire” by trying to also expand the reservoir’s capacity.

Water in the dam would likely have to be lowered or completely drained during the project in order to take enough pressure off the dam. Those lower water levels could cause ripples in regional water-supply operations, especially in a dry year.

But Dan Birch, the district’s assistant general manager, said water-supply concerns would not be the tail that wags the dog of the rehabilitation project and related safety concerns.

However, it was also noted that the project would take 220 days over two construction seasons and would likely have an affect on four years of water operations in all.

“It could have some impact on water operations for one year pre- and one year post-construction,” Currier said.

Currier and other engineers plan on continuing their analysis of the proposed solution, including meeting with the state dam safety engineer in August and continuing to ask a panel of experts to peer review the plans.

A refined proposal will be presented to the River District board in September as part of the district’s annual budget meetings.

Editor’s note: Aspen Journalism is collaborating with the Glenwood Springs Post Independent and The Aspen Times on coverage of rivers and water. The Post Independent published this story on July 27, 2015.

Transmountain diversion concepts discussed in Rifle — Aspen Journalism #COWaterPlan #ColoradoRiver #CORiver

Homestake Dam via Aspen Journalism
The dam that forms Homestake Reservoir on Homestake Creek, a tributary of the Eagle River. An agreement allows for more water to be developed as part of this transmountain diversion project.

From Aspen Journalism (Brent Gardner-Smith):

James Eklund, the director of the Colorado Water Conservation Board, invoked his Western Slope heritage at a “Summit on the Colorado Water Plan” hosted Saturday in Rifle by the Garfield County commissioners.

“The mantra I grew up with in Plateau Valley was not one more drop of water will be moved from this side of the state to the other,” said Eklund, whose mother’s family has been ranching in the Plateau Creek valley near Collbran since the 1880s.

Eklund was speaking to a room of about 50 people, including representatives from 14 Western Slope counties, all of whom had been invited by the Garfield County commissioners for a four-hour meeting.

The commissioners’ stated goal for the meeting was to develop a unified voice from the Western Slope stating that “no more water” be diverted to the Front Range.

“That argument had been made, probably by my great-grandparents, my grandparents and my parents,” Eklund said. “And I know there are a lot of people who still want to make that argument today, and I get that. But it has not done us well on the Western Slope.

“That argument has gotten us to were we are now, 500,000 to 600,000 acre feet of water moving from the west to the east. So I guess the status quo is not West Slope-friendly. We need something different. We need a different path. And these seven points provides that different path.”

The “seven points” form the basis of a “draft conceptual framework” for future negotiations regarding a potential transmountain diversion in Colorado.

The framework is the result of the ongoing statewide water-supply planning process that Eklund is overseeing in his role at the CWCB.

Eklund took the helm two years ago at the CWCB after serving as Gov. John Hickenlooper’s senior deputy legal counsel, and he’s been leading the effort to produce the state’s first water plan, which is due on the governor’s desk in December.

The second draft of the plan includes the seven points, even though the Colorado River Basin Roundtable, which meets monthly in Glenwood Springs under the auspices of the CWCB, is still on the record as opposing their inclusion in the water plan. That could change after its meeting on Monday.

The outflow of the Bousted Tunnel just above Turquoise Reservoir near Leadville. The tunnel moves water from tributaries of the Roaring Fork and Fryingpan rivers under the Continental Divide for use by Front Range cities, and Pitkin County officials have concerns that more water will someday be sent through it.
The outflow of the Bousted Tunnel just above Turquoise Reservoir near Leadville. The tunnel moves water from tributaries of the Roaring Fork and Fryingpan rivers under the Continental Divide for use by Front Range cities, and Pitkin County officials have concerns that more water will someday be sent through it.

Not legally binding

The “seven points” seeks to define the issues the Western Slope likely has with more water flowing east under the Continental Divide, and especially how a new transmountain diversion could hasten a demand from California for Colorado’s water under the 1922 Colorado River Compact.

“The seven points are uniquely helpful to Western Slope interests because if you tick through them, they are statements that the Front Range doesn’t necessarily have to make,” Eklund said in response to a question. “If these were legally binding, the Western Slope would benefit.”

Under Colorado water law a Front Range water provider, say, can file for a right to move water to the east, and a local county or water district might have little recourse other than perhaps to fight the effort through a permitting process.

But Eklund said the points in the “conceptual framework” could be invoked by the broader Western Slope when negotiating a new transmountain diversion.

As such, a diverter might at least have to acknowledge that water may not be available in dry years, that the diversion shouldn’t exacerbate efforts to forestall a compact call, that other water options on the Front Range, including increased conservation, should be developed first, that a new transmountain diversion shouldn’t preclude future growth on the Western Slope, and that the environmental resiliency of the donor river would need to be addressed.

“We’re just better off with them than without them,” Eklund said of the seven points.

The downstream face of the dam that forms Homestake Reservoir on Homestake Creek, a tributary of the upper Eagle River. A tunnel moves water from Homestake Reservoir to Turquoise Reservoir, near Leadville.
The downstream face of the dam that forms Homestake Reservoir on Homestake Creek, a tributary of the upper Eagle River. A tunnel moves water from Homestake Reservoir to Turquoise Reservoir, near Leadville.

A cap on the Colorado?

Eric Kuhn, the general manager of the Colorado River District, which is based in Glenwood Springs and represents 15 Western Slope counties, told the attendees that three existing agreements effectively cap how much more water can be diverted from the upper Colorado River and its tributaries above Glenwood Springs.

The Colorado Water Cooperative Agreement, which was signed in 2013 by 18 entities, allows Denver Water to develop another 18,000 acre-feet from the Fraser River as part of the Moffat, or Gross Reservoir, project, but it also includes a provision that would restrict other participating Front Range water providers from developing water from the upper Colorado River.

A second agreement will allow Northern Water to move another 30,000 acre feet of water out of the Colorado River through its Windy Gap facilities, but Northern has agreed that if it develops future projects, it will have to do so in a cooperative manner with West Slope interests.

And a third agreement known as the Eagle River Memorandum of Understanding will allow Aurora and Colorado Springs to develop another 20,000 acre feet of water as part of the Homestake project in the Eagle River basin, but will also provide 10,000 acre feet for Western Slope use.

“So effectively these three agreements, in effect, cap what you’re going to see above Glenwood Springs,” Kuhn said.

The Moffat, Windy Gap and Eagle River projects are not subject to the “seven points” in the conceptual agreement, and neither is the water that could be taken by the full use of these and other existing transmountain projects.

“So when you add all that up, there is an additional 100,000 to 150,000 acre-feet of consumptive use already in existing projects,” Kuhn said.

But beyond that, Kuhn said Front Range water providers desire security and want to avoid a compact call, just as the Western Slope does.

“We’ve been cussing and discussing transmountain diversions for 85 years,” Kuhn added, noting that the Colorado Constitution does not allow the Western Slope to simply say “no” to Front Range water developers.

“So, the framework is an agenda,” Kuhn said, referring to the “seven points.” “It’s not the law, but it is a good agenda to keep us on track. It includes important new concepts, like avoiding over development and protecting existing uses.”

rquoise Reservoir, which stores water brought under the Continental Divide from the Eagle, Fryingpan and Roaring Fork river headwaters.
rquoise Reservoir, which stores water brought under the Continental Divide from the Eagle, Fryingpan and Roaring Fork river headwaters.

Vet other projects too?

Rachel Richards, a Pitkin County commissioner, told the attendees that she would like to see more water projects than just new transmountain diversions be subject to the seven points.

As part of the state’s water-supply planning efforts, state officials have designated a list of projects as already “identified projects and processes,” or IPPs, which are not subject to the seven points.

“We would like to see the same environmental standards, and community buy-in standards, applied to increasing existing transmountain diversions or IPPs,” Richards said, noting that the “IPPs” seem to be wearing a halo.

“They need to go through just as much vetting for concern of the communities as a new transmountain diversion would, and we’re probably going to see a lot more of them first,” she said.

At the end of the four-hour summit on the statewide water plan, Garfield County Commissioner Mike Sampson said he still had “real concerns” about the long-term viability of Western Slope agriculture and industry in the face of growth on the Front Range, but he offered some support for the seven points.

“I think the seven points is probably a good starting position,” Sampson said.

He also said Garfield County would make some edits to a draft position paper it hopes will be adopted by other Western Slope counties.

On Saturday, the draft paper said “the elected county commissioners on the Western Slope of Colorado stand united in opposing any more major, transmountain diversions or major changes in operation of existing projects unless agreed to by all of the county(s) from which water would be diverted.”

But Sampson was advised, and agreed, that it might be productive to reframe that key statement to articulate what the Western Slope would support, not what it would oppose.

Editor’s note: Aspen Journalism is collaborating with the Glenwood Springs Post Independent and The Aspen Times on coverage of rivers and water. The Post published this story online on July 25, 2015.

More Colorado Water Plan coverage here.

State water board rules against Glenwood’s proposed whitewater rights — Aspen Journalism #ColoradoRiver

Upstream view of the Colorado River at the mouth of the Roaring fork River
Upstream view of the Colorado River at the mouth of the Roaring fork River

From Aspen Journalism (Brent Gardner-Smith):

IGNACIO — The ongoing effort by the city of Glenwood Springs to establish a new water right for three potential whitewater parks on the Colorado River was dealt a setback Thursday by the directors of the Colorado Water Conservation Board.

The CWCB board voted 8-to-1 to adopt staff “findings of fact” that the proposed water rights for a “recreational in-channel diversion,” or RICD, would “impair Colorado’s ability to fully develop its compact entitlements” and would not promote “the maximum beneficial use of water” in the state.

James Eklund, the director of the CWCB, and a nonvoting board member, was asked after the meeting what he would tell a kayaker in Glenwood about the board’s vote on Thursday.

“These are complicated issues,” Eklund said. “The CWCB values recreational water projects and takes very seriously its charge to strike a balance among recreational, environmental and consumptive uses. The proponent’s data and analysis weren’t able to demonstrate that the RICD as proposed struck this balance to the satisfaction of the CWCB.”

The CWCB board is required by state law to review all applications made in water courts for new recreational water rights, and to make a determination if the water right would prevent the state from developing all the water it legally can.

Colorado’s “compact entitlements” stem from the 1922 Colorado River Compact, which requires seven Western states to share water from the larger Colorado River basin.

The compact requires that an unspecified amount of water be divided between Colorado, Utah and Wyoming, and estimates of the amount of water Colorado can still develop under the compact range from zero to 400,000 acre-feet to 1.5 million acre-feet.

Mark Hamilton, an attorney with Holland and Hart representing Glenwood, told the CWCB board members Thursday that there would be “no material impairment” to the state’s ability to develop new water supplies.

“If the issue really is what’s the additional upstream development potential, we would point out that significant upstream development can still occur,” Hamilton said.

Hamilton also said that the recreational water right would be non-consumptive, meaning the water would stay in the river and simply flow over u-shaped, wave-producing concrete forms embedded into the riverbed.

Glenwood is seeking the right to call for 1,250 cubic feet per second of water to be delivered to three whitewater parks at No Name, Horseshoe Bend and Two Rivers Park, from April 1 to Sept. 30.

It also wants the right to call for 2,500 cfs for up to 46 days between April 30 and July 23, and to call for 4,000 cfs on five consecutive days sometime between May 11 and July 6 in order to host a whitewater competition.

Aurora and Colorado Springs, together as partners in the Homestake transmountain diversion project, are opposing Glenwood’s water rights application, which was filed in December 2013.

“We do not oppose reasonable RICDs, but we believe this RICD claim is extraordinary by any measure,” Joseph Stibrich, the water resources policy manager for the city of Aurora, told the CWCB board, which was meeting in Ignacio on the Southern Ute Indian Reservation.

“We believe that a water claim of over 581,000 acre feet will seriously impair full development of Colorado’s compact entitlement,” Stibrich said. “This claim will severely impact the state of Colorado’s ability to meet its future water needs.”

Stibrich also said “this RICD is going to shift the burden of water supply development to meet the future needs of the state to the Yampa, to the Gunnison, and to the Rio Grande basins, while promoting further dry-up of irrigated lands throughout the state.”

Denver Water is also opposing Glenwood’s water rights application.

As part of the Colorado River Cooperative Agreement, Denver Water agreed not to oppose a RICD application from Glenwood, but only if Glenwood did not seek a flow greater than 1,250 cubic feet per second, which is the same size as the senior water right tied to the Shoshone hydropower plant.

Casey Funk, an attorney with Denver Water, said the utility stands by its agreement, but since Glenwood has asked for more than 1,250 cfs, it is opposing the city’s water court application. However, Funk said Denver Water is willing to keep negotiating with Glenwood.

The city made the case on Thursday that it was asking for more than 1,250 cfs on only 46 days between April and September, and it was doing so because the stretch of the Colorado from Grizzly to Two Rivers Park was more fun to float at 2,500 cfs than 1,250 cfs.

According to testimony Thursday, Glenwood also offered to include a “carve-out” in its water right to allow for 20,000 acre-feet of water to be diverted, stored and transported upstream of the proposed whitewater parks at some point in the future.

But that did not do much to sway the concerns of the CWCB staff.

“Staff is concerned with this provision, as it does not include water rights for transmountain diversions,” stated a July 15 memo to the CWCB board from Ted Kowalski and Suzanne Sellers of the CWCB’s Interstate, Federal & Water Information Section.

The CWCB staff memo also found that Glenwood’s recreational water rights would “exacerbate the call on the river and materially impact the ability of the state to fully use its compact entitlements because the RICDs will pull a substantial amount of water downstream.”

Peter Fleming, the general counsel for the Colorado River District, suggested the CWCB board give the parties in the case more time to continue negotiating before it ruled on its staffs’ findings.

The River District, which is also a party to Glenwood’s water court case, represents 15 counties on the Western Slope.

“We think that compact issues are effectively done,” Fleming told the board about Glenwood’s application. “We believe there is sufficient water above the RICD to develop.”

But the CWCB board did not take Fleming’s suggestion, and after relatively little debate and discussion, a motion was made to accept the staff’s findings that Glenwood’s RICD failed two of the three criteria the CWCB board was supposed to rule on.

“I think it is really unfortunate that the board took the approach they did,” said Nathan Fey, the Colorado stewardship director for American Whitewater, after the board’s decision against Glenwood.

American Whitewater and Western Resource Advocates are both parties in the water court case, and they are supporting Glenwood’s application.

“It is unclear what evidence the staff presented that shows it is of material impairment to developing our water, or maximizing use of the state’s water,” Fey said. “Those are significant concerns, but I don’t think the state made a very strong case on those points. And it sounds like we would prefer to see another transmountain diversion and some future use on the Front Range, rather than protect the current river uses we have in our communities, like Glenwood Springs, now.”

The board’s finding will now be sent to the Division 5 Water Court in Glenwood Springs, where the city filed its water rights application and the process is still unfolding.

And while the CWCB board’s determination is not binding on a water court judge, it has to be considered by the court as part of the ongoing case.

But Hamilton, Glenwood’s attorney, said after the meeting that the court would also need to consider additional balancing information presented by Glenwood.

It could be an uphill journey for Glenwood, though, as the CWCB staff has also been directed by the CWCB board to remain a party in the water court case and to defend its “findings of fact,” which includes more issues than were considered by the CWCB on Thursday.

Given the board’s vote on Thursday, Stibrich of Aurora said settlement discussions with Glenwood Springs are now likely.

“I’m certain they will make overtures to us and we’ll talk,” Stibrich said. “We’ll see if something can be reached or not.”

Editor’s note: Aspen Journalism is collaborating with the Glenwood Springs Post Independent and The Aspen Times on coverage of rivers and water. The Post Independent published this story online on July 16, 2015.

More whitewater coverage here.

City of Glenwood Springs proposed whitewater parks via Aspen Journalism
City of Glenwood Springs proposed whitewater parks via Aspen Journalism

Granby: “State of the River” meeting recap #ColoradoRiver

Historical Colorado River between Granby and Hot Sulphur Springs
Historical Colorado River between Granby and Hot Sulphur Springs

From the Sky-Hi Daily News (Hank Shell):

During the meeting, officials from the Upper Colorado River Basin’s biggest water interests including Northern Water, Denver Water and the U.S. Bureau of Reclamation spoke about some of the basin’s biggest issues, including the state of runoff and snowpack in the region and the movement at Ritschard Dam on Wolford Mountain Reservoir.

Though snowpack seemed to falter during what proved to be a rather dry March, it’s been building steadily over the last three to four weeks, explained Don Meyer with the Colorado River District.

The variations in snowpack have pushed the basin into “uncharted territory,” he said.

“I think the message here is think 2010 in terms of snowpack,” Meyer said.

Though he added that snowpack is not analogous to runoff, Meyer said 2015 “will likely eclipse 2010 in terms of stream flow.”

Victor Lee with the U.S. Bureau of Reclamation echoed Meyer, adding that recent cold temperatures across the region have allowed snowpack to persist.

Though snowpack is currently below average, it could linger past the point at which the average snowpack tends to drop…

If the current snowpack does translate into high runoff in Grand County, there may not be anywhere to put it, Lee said.

Front Range reservoirs are full, and storage in Lake Granby is the highest it’s ever been for this time of year, according to Lee’s presentation…

Though it could be a good runoff year for Grand County, Meyer said that snow-water equivalent above Lake Powell is still well below average, making it a dry year for the Upper Colorado River Basin overall.

RITSCHARD DAM

Officials aren’t sure when the settling and movement at Ritschard Dam will stop, but it poses no threat to safety, said John Currier with the Colorado River District.

“We really are absolutely confident that we don’t have an imminent safety problem with this dam,” Currier said…

ENDANGERED FISH

The Bureau of Reclamation will increase flows from the Granby Dam to 1,500 CFS around May 29 and maintain those flows until around June 8, Lee said.

The releases will be part of an endangered fish recovery program and will be coordinated with releases from other basin reservoirs to enhance peak flows in the Grand Valley where the plan is focused.

Wolford Mountain Reservoir will also participate in the coordinated releases, Meyer said.

The program hopes to re-establish bonytail chub, Colorado pikeminnow, razorback sucker and humpback chub populations to a 15-mile stretch of the Colorado River above Grand Junction.

WINDY GAP FIRMING

After receiving its Record of Decision last year, the Windy Gap Firming Project’s next major hurdle is acquiring a Section 404 permit from the Army Corps of Engineers for the construction of Chimney Hollow Reservoir, said Don Carlson with Northern Water.

The permit regulates dredged or fill material into water as part of the Clean Water Act.

Northern Water hopes to acquire the permit this year, with construction possibly beginning in 2016 or 2017, Carlson said.

The project seeks to firm up the Windy Gap water right with a new Front Range reservoir. The project currently stores water in Lake Granby.

Because it’s a junior water right, yield for the project is little to nothing in dry years.

Northern Water also hopes to establish a free-flowing channel of the Colorado River beside the Windy Gap Reservoir as part of the Windy Gap Reservoir Bypass Project.

The new channel would allow for fish migration and improve aquatic habitat along the Colorado River.

That project still needs $6 million of its projected $10 million cost.

MOFFAT TUNNEL FLOWS

Moffat Tunnel flows are hovering around 15 CFS as Denver Water is getting high yield from its Boulder Creek water right, said Bob Steger with Denver Water.

The increased yield from that junior water right means flows through Moffat Tunnel will remain low through early summer, Steger said.

“The point is we’ll be taking a lot less water than we normally do,” he said.

Denver Water expects its flows through the tunnel to increase in late summer as its yield from Boulder Creek drops, Steger said.

Williams Fork Reservoir, which is used to fulfill Denver Water’s obligations on the Western Slope, is expected to fill in three to four weeks, Steger said.

More Colorado River Basin coverage here.

The 1st quarter Colorado River District board meeting summary is hot off the presses #ColoradoRiver

Ritschard Dam movement graphic Colorado River District
Ritschard Dam movement graphic Colorado River District

Click here to read the summary. Here’s an excerpt:

The Colorado River District owns and operates the Ritschard Dam forming Wolford Mountain Reservoir near Kremmling in Grand County. It is a clay-core, rock fill dam that has experienced settling beyond the amounts normally expected by designers for a dam of this type.

The dam is safe and will con􏰁nue to be safe in the future, according to the District’s engineering staff. Engineering consultants engaged by the Colorado River District to study the problem since 2009, as well as the Dam Safety Branch of the Colorado Division of Water Resources agree that the dam is safe and poses no danger.

To maintain that standard, after an aggressive five-year investigation that included installation and monitoring of sophisticated instruments to measure the movements, the Colorado River District will decide this year on a renovation and repair scenario.

Since the dam was constructed in 1995, it has settled near its center by about two feet, a foot more than anticipated. Along with this settlement, the crest of the dam has shifted downstream by about eight inches.

Engineering consultants engaged by the Colorado River District to study the problem since 2009, as well as the Dam Safety Branch of the Colorado Division of Water Resources say the dam is safe and poses no danger.

Out of an abundance of caution, Colorado River District Chief Engineer John Currier said enough informa􏰁on has been compiled to identify by mid-year the repair options and advise the Colorado River District Board of Directors on the proper one to choose.

Consultants from AECOM (formerly URS) and River District staff briefed the Board of Directors on the condition and analysis of the dam at its January quarterly in Glenwood Springs.

“We as a staff think it is incumbent upon us as an organiza􏰁on to really start moving this issue down the road,” Currier said. He noted that computer modeling of the se􏰂lement suggests that in future years, safety might be compromised, so a solution will be identified this year.

Although Colorado’s chief of dam safety has not placed an operational restriction on the dam, the Colorado River District will continue with the cautionary policy it began in 2014. Once the reservoir fills this spring, it will be immediately lowered by 10 feet in elevation. The lower water level has been shown by instrumentation to slow down settlement trends.

According to Currier, at that lower level, the Colorado River District can still meet its water contracting delivery needs, as well as obligations to endangered fish releases to the Colorado River.

Also still protected is Denver Water’s leasehold interest in a portion of the storage that it employs in dry years to compensate for water it stores in Dillon Reservoir out of priority over Green Mountain Reservoir. At 10 feet down, recreational use will not be adversely affected.

By the Board’s quarterly meeting in July, AECOM and staff will have repair scenarios to consider, including comparative costs.

AECOM engineers told the Board that the culprit in the settlement was a poorly compacted rock fill shell that surrounds the clay core on the upstream and downstream sides.

In such a dam, the clay core material is the impervious element in the dam. The rock fill shell supports the core. All dams, whether concrete or earthen, seep water.

At Ritschard Dam, filters meant to collect seepage are in excellent shape and are doing their job. Seepage does not show any effects from the settlement, Currier said.

More Colorado River District coverage here.