#cwcsc16: Colorado Water Congress Summer Conference 2016

Steamboat Springs
Steamboat Springs

I’m at the conference getting ready for the first session: Leading the way with direct potable reuse in Colorado. Panel with moderator Doug Kemper (Colorado Water Congress), Myron Nealey (Denver Water), John Rehring (Carollo Engineers).

CWC has an iPhone app up at the app store. Search for CWC and scroll down to CWC Summer Conference.

Nice bike ride up the Yampa River from my campsite west of town. The Sheraton Steamboat Springs lets you check your bike and park it in a room out of the elements.

#ColoradoRiver: The Plan to Strengthen Denver’s Water Supply — 5280.com #COriver

Gross Dam enlargement concept graphic via Denver Water
Gross Dam enlargement concept graphic via Denver Water

From 5280.cm (Amy Thomson):

Considering the Denver region is growing by an average of 4,500 new residents per month, a large sector of the population likely doesn’t remember the catastrophic 2002 drought. The most severe water shortage since the Dust Bowl, snowpack and soil moisture were at all-time lows, and we remained in a dry period until 2006. Luckily, with water restrictions in place, we never actually ran out of water—we just got really close.

“We realized that we had an immediate need to correct a vulnerability in our system,” Denver Water CEO Jim Lochhead says. That’s when Denver Water started planning the Gross Reservoir Expansion Project, and after more than a decade of negotiations, the project (which was recently endorsed by Gov. John Hickenlooper) is underway.

But will it be enough? The short answer is yes—as long as Denverites work on strengthening their water conservation practices. Lochhead was pleased to note that when a storm comes through the Mile High City, there is a noticeable drop in outdoor water use, because well-informed residents are turning off their sprinkler systems. Denver residents have managed to reduce water consumption by more than 20 percent in the last 15 years, even with a 15 percent increase in population, according to Lochhead.

The decrease is not enough to mitigate the risk of drought, however. As Colorado’s largest water utility, the Denver Water system is made up of two collection systems—the Northern and the South Platte—and they are incredibly imbalanced. About 80 percent of the water comes from the south system, leaving the north very vulnerable to low rainfall or wildfires. During the notable dry years of 2002 and 2013, clients in the north end were lucky their taps continued to flow.

“We were literally only one drought away from a major problem in our system,” Lochhead says, noting that as recently as 2013, the system was virtually out of water in the north-end.

@DenverWater: Monthly #conservation tips

Orr Manufacturing Vertical Impact Sprinkler circa 1928 via the Irrigation Museum
Orr Manufacturing Vertical Impact Sprinkler circa 1928 via the Irrigation Museum

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

This summer has been a hot one, but the sizzle doesn’t have to burn out your water-wise mindset.

Here are recommended lawn watering times for August:

  • Fixed spray heads: 14 minutes per zone
  • Rotary/high-efficiency nozzles: 34 minutes per zone
  • Rotor heads: 27 minutes per zone
  • Manual sprinklers: 20 minutes per zone
  • On watering days — limited by the rules to no more than three a week — you can make each minute matter by cycling and soaking. Water when the time is right, which is easy if you remember that time never falls between 10 a.m. and 6 p.m.

    Water only when your lawn needs a drink. Besides wasting water — and your money — overwatering can lead to weeds, disease and dreaded fungus.

    And here’s a hot tip for smart savings indoors: Our rebates changed this year, so be sure to look up which toilets qualify for rebates before you buy. Only WaterSense-labeled toilets averaging 1.1 gallons or less per flush qualify for a $150 rebate. With a little bit of research, you and your new rebate-worthy throne can rule the world of efficiency.

    Denver Water CEO calls for more flexibility in water management — Aspen Journalism

    The dam that forms Gross Reservoir, located in the mountains west of Boulder. Photo: Brent Gardner-Smith/Aspen Journalism
    The dam that forms Gross Reservoir, located in the mountains west of Boulder. Photo: Brent Gardner-Smith/Aspen Journalism

    From Aspen Journalism (Allen Best):

    Jim Lochhead, the CEO and manager of Denver Water, said Tuesday that building new dams in the Colorado River basin is not at the top of his to-do list. Nor, for that matter, is drying up farms to provide water for Colorado’s growing cities.

    But he says Colorado still needs to have hard conversations about how to flexibly manage its water. In particular, he wants farmers to be able to share water with Denver and other cities without worrying that they may lose their water rights.

    Speaking at the annual Western Water Symposium at Colorado State University, Lochhead credited the 2015 Colorado Water Plan as being a useful “compendium of the issues” but said it highlighted relatively easy solutions without fully addressing the harder challenges.

    “I don’t think the solution is $20 billion of new water projects for Colorado, but that’s an easy thing to go look for,” said Lochhead, head of the state’s largest water utility that supplies 1.4 million people, and stores nearly 40 percent of its water in Summit County’s Dillon Reservoir.

    A coordinated plan is needed, Lochhead said.

    “We’re not there yet with the state water plan to develop any kind of coordinated principle vision for the future, much less how to get there,” he said.

    Lochhead, who took the helm of Denver Water in 2010, described Colorado’s historical approach to water as a zero-sum game where there had to be a winner and a loser.

    That zero-sum game lost its moorings in the second half of 20th century as a result of new federal and state laws, court decisions and political fights, Lochhead said.

    He said that two decades have brought more collaboration between diverse interests, including those on both sides of the Continental Divide, and it is reflected in such projects as Wolford Mountain Reservoir near Kremmling.

    Both Denver Water and the Colorado River Water Conservation District have an interest in Wolford Reservoir, with Denver Water on track to soon own 40 percent of the water in the reservoir. The water has many benefits, among them providing late-summer water to meet needs of four endangered fish species in the Colorado River near Grand Junction.

    Another collaborative effort has been launched in the Winter Park area. There, Denver plans to increase diversions from the Fraser and Williams Fork rivers, but is doing so with the blessing of local authorities, thanks to a collaborative “learning by doing” effort in Grand County that seeks to reduce streamflow impacts from both new and existing diversions.

    But Lochhead believes Colorado must still dramatically change its water allocation methods as it faces population growth. Demographers project that Colorado’s 5.4 million population will double within a few decades. If we seek to provide the water for the additional residents the way we provided for the first 5 million, he said, “we won’t like the outcome very well.”

    Gore Canyon rafting via Blogspot.com
    Gore Canyon rafting via Blogspot.com

    The river itself

    A second challenge is the Colorado River itself, the fountain that supplies at least part of the water for 40 million people, from corn farms in northeastern Colorado to San Diego. And despite some good snow years, the two big reservoirs on the lower Colorado River, Lake Powell and Lake Mead, are both low enough to keep a ballroom full of water experts up at night.

    It could get worse. And, according to projections of climate models, it likely will.

    Laurna Kaatz, an in-house climate expert at Denver Water, recently told the Metro basin roundtable it’s still not clear if it will be hotter and drier, or hotter and wetter in Colorado in the future, but there is little doubt it will be hotter.

    More major dams on the Colorado River are not the solution, Lochhead said. Evaporative losses would result in more loss than gain, he said, although he did allow for the possibility of relatively small dams.

    Denver Water is, however, studying the potential for putting water into aquifers beneath the city, creating underground storage — storage that could, in theory, hold water from the Western Slope.

    And Denver Water is looking to store up to an additional 15,000 acre-feet of Western Slope water in an expanded Gross Reservoir, southwest of Boulder. The $360 million project seeks to raise the elevation of the dam by 131 feet, which would increase the capacity of the reservoir by 77,000 acre-feet, bringing it up to 119,000 acre-feet.

    Flexibility needed

    Lochhead said that Colorado needs more flexible water management options that allow for greater sharing of the resource.

    About 85 percent of water in Colorado is used by agriculture and ranchers and farmers tend to have the oldest and most senior water rights.

    Water rights are private, said Lochhead, “but you can’t really do anything with that property right except what you are currently doing with it unless you go to water court. And by going to water court you put that entire water right at risk.”

    In Colorado’s water courts, objections to changes in uses of water rights are often filed. The process can be lengthy and expensive for those seeking to make changes.

    “You need a safe process where you don’t have to put your water right at risk, and you understand that you don’t have to spend years negotiating,” he said.

    And Lochhead thinks Colorado also needs another conversation about conservation, where the emphasis is not about sacrifice but about innovation.

    Denver Water intends to demonstrate what is possible as it redevelops its 35-acre headquarters campus along Interstate 25 near downtown Denver. There, planners think they can reduce demand for potable water by more than 50 percent.

    In water reuse, said Lochhead, Colorado is “way behind the curve” as compared to some world cities, including Amsterdam and Sydney.

    Editor’s note: Aspen Journalism and the Aspen Daily News are collaborating on the coverage of water and rivers. The Daily News published this story on Friday, July 29, 2016.

    The August 2016 “Water News” is hot off the presses from @DenverWater

    Eleven Mile Canyon Reservoir, completed in 1932, is the second largest storage facility in Denver Water’s system and one of the largest bodies of water on Colorado’s East Slope. Photo via Denver Water.
    Eleven Mile Canyon Reservoir, completed in 1932, is the second largest storage facility in Denver Water’s system and one of the largest bodies of water on Colorado’s East Slope. Photo via Denver Water.

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

    Denver Water has 20 dams, and some are more than 100 years old. We conduct our own internal dam evaluations and also take part in state and federal inspections, which include checking for any mechanical issues and changes in seepage over time.

    We also actively work to maintain and improve dams. Two of Denver Water’s oldest earthen dams (Antero, 1909, and Marston, 1902) have been undergoing safety upgrades.

    Concrete dams are expected to last 200 years, and we aim to maintain them so they can safely last even longer. Built in 1932, Eleven Mile had its annual state and internal inspection in May, when the dam received a standard “satisfactory” rating.

    With proper maintenance, we can expect this 84-year-old architectural marvel to last well beyond the next century.

    Denver Water digs into Vasquez Canal Project — The Sky-Hi Daily News

    The south portal of the Vasquez Tunnel is shown in this 1957 photo. Via Denver Water.
    The south portal of the Vasquez Tunnel is shown in this 1957 photo. Via Denver Water.

    From the Sky-Hi Daily News (Lance Maggart):

    The Vasquez Canal Project is a multi-year multi-million dollar project that continues efforts by Denver Water to improve existing water diversion infrastructure. Work on the Vasquez Canal Project focuses on removing sections of the existing Vasquez Canal and replacing removed sections with a 114-inch diameter concrete reinforced pipe.

    Work on the project has occurred in previous year with Denver Water replacing between 5,000 and 6,000 feet of the Vasquez Canal over the past two decades. Officials from Denver Water say they plan to replace about 2,000 feet of the Vasquez Canal in 2016, leaving roughly 15,000 feet to be replaced in the future.

    Officials from Denver Water did not provide an overall projected cost on the project pointing out that, “funding allocation for this project is reassessed annually”. In previous year the project averaged around $750,000 per year in costs. Future projected cost estimates on the Vasquez Canal Project total between two to three million dollars annually.

    Monies used for the project come directly from Denver Water which is funding operation, as it does all operational and capital projects, through water rate fees, bond sales, cash reserves, hydropower sales and system development charges for new services.

    Work on the Vasquez Canal Project consists primarily of excavation and earth moving to facilitate the canal upgrade. “Crews will demolish the old concrete liner and covers, excavate the area and install the new 114-inch pipe, piece by piece,” stated Denver Water Communication Specialist Jimmy Luthye. Luthye explained Denver Water plans to, “work aggressively to complete this project in the next few years in an effort to replace aging infrastructure and improve the safety and strength of the entire water system.”

    Ames Construction is the contractor of record for the project. For the past 20 years though, as previous sections of the Vasquez Canal have been replaced, employees of Denver Water performed the upgrade work. According to Denver Water this is the first year work on the project has been contracted out.

    The Arapaho National Forest prepared an environmental assessment of the Vasquez Canal Project. All construction work on the project is being conducted entirely on National Forest System Lands. According to Denver Water that environmental assessment determined, “there would be no significant environmental impacts.” Officials from Denver Water went on to state, “They approved the project along with required best management practices, design criteria and monitoring designed to protect the area during construction.”

    The Vasquez Canal is part of Denver Water’s historic water diversion network that brings mountain runoff to the Front Range and Denver Metro area. The original canal was completed in the late 1930s. According to Denver Water, information on the original construction of the canal is fairly limited but officials from the municipal water supplier stated, “we suspect that some of it (Vasquez Canal) was originally dug by hand because the canal had to be cut into the side of a steep mountain… making it difficult for machines to access.”

    In the late 1950s Denver Water covered the originally open Vasquez Canal, effectively creating a tunnel. A drought during the early 1950s prompted the action, which was intended to mitigate evaporation as water traveled through the diversion system.

    Water utilized by the Denver Water’s diversion system follows a zigzagging path of infrastructure as it descends from snowmelt in the high Rockies to homes along the Front Range.

    Diversion structures in the Upper Williams Fork River send water through the Gumlick Tunnel, formerly known as the Jones Pass Tunnel, where the water passes under the Continental Divide. From there water travels through the Vasquez Tunnel, which brings the water back through to the other side of the Continental Divide, where it enters into Grand County and Vasquez Creek. The water is then diverted through the Moffat Tunnel back under the Continental Divide for a final time and into South Boulder Creek, feeding into Gross Reservoir, a major water storage reservoir for Denver Water.

    Colorado transmountain diversions via the University of Colorado
    Colorado transmountain diversions via the University of Colorado

    Denver Water distances itself from risk assessment of Ritschard Dam at Wolford Reservoir

    A truck drives out to Ritschard Dam, which forms Wolford Reservoir, on July 13, 2016. The dam has settled two feet downward and moved eight inches horizontally since being built in 1995.
    A truck drives out to Ritschard Dam, which forms Wolford Reservoir, on July 13, 2016. The dam has settled 2 feet downward and moved 8 inches horizontally since being built in 1995.

    By Brent Gardner-Smith, Aspen Journalism

    KREMMLING – Denver Water has taken steps to distance itself from a recent risk assessment of Ritschard Dam, which forms Wolford Reservoir five miles north of Kremmling.

    The 21-year-old dam has found to be moving slightly and settling more than normal and a risk analysis workshop was held in February by a group of experts assembled by the Colorado River District, which owns the dam and reservoir.

    After the risk workshop John Currier, the chief engineer for the River District, wrote a memo to the district’s board saying “a key conclusion” of a consultant review board is that “the dam is safe” and “there is no need for immediate action.”

    Currier also wrote in his April 7 memo that the “key parties and participants” in the February risk workshop “included 1) the State Dam Safety Branch, 2) Denver Water, 3) our consultant review board, 4) our engineer, AECOM and 5) River District staff.”

    But on May 2, Robert Mahoney, the director of engineering for Denver Water, sent Currier a letter critical of his April memo.

    “In the memorandum, you characterize Denver Water as a ‘risk estimator’ and an active participant during the workshop,” Mahoney wrote. “Denver Water takes exception to these characterizations. At no time did Denver Water participate in the workshop as a risk estimator, nor was it ever invited to participate as a risk estimator on the panel.”

    Mahoney also said that Denver Water “disagrees with characterizations in the memorandum implying that Denver Water was an active participant and that we concluded and agreed with the findings of the risk estimators. Denver Water’s role in attending the workshop was that of a concerned observer.”

    Currier included the letter from Denver Water in a July 7 memo to the River District board. The memo and the letter were made public this week when the public agenda was released for the district’s July 20 board meeting in Glenwood Springs.

    Mahoney raised other concerns in his letter as well.

    “Based on our observations, the workshop and your memorandum only addressed the probability of a dam failure consequence,” Mahoney wrote. “While the probability of a dam failure appears low, dam failure is not the only potential adverse impact of concern to Denver Water. The probability of cracking in the core of the dam, which could reduce storage capacity, has a much greater range of uncertainty.”

    Denver Water currently leases 40 percent of the water in Wolford Reservoir from the River District.

    The reservoir can store 66,000 acre-feet of water and on July 14 the dam was holding back 65,240 acre-feet.

    When its lease expires at the end of 2020, Denver Water is slated to become a part owner of the water in the reservoir.

    “The River District will convey ownership, use and control of 40 percent of storage space and water right in Wolford Reservoir to Denver Water,” according to Jimmy Luthye, a communications specialist with Denver Water who checked Friday on the status of Denver Water’s stake in the facility.

    As Jim Pokrandt, director of community affairs at the Colorado River District put it on Friday, “Denver Water currently holds a 40 percent lease. After 2019, it will be a 40 percent owner.”

    The upstream side of Ritschard Dam, which forms Wolford Reservoir.
    The upstream side of Ritschard Dam, which forms Wolford Reservoir.

    Dam has issues

    In his letter, Mahoney also suggested that developing a plan to fix the dam would be “beneficial.”

    “According to Mr. Dick Davidson (of AECOM), cracking of the core has a 50 percent annual probability of occurrence starting in 20 years (the time criteria set for the workshop and probability estimation),” Mahoney wrote. “Given this uncertainty, it would be beneficial to develop plans now to remediate Ritschard Dam in the event of a crack.

    “Further, based on the information presented at the workshop, Denver Water does not agree that Ritschard Dam is functioning as designed because no dam is designed to function with the degree of movement observed at Ritschard Dam to date.

    “As addressed in the April 27, 2016 letter from Bill McCormick, chief of the Dam Safety Branch of the state engineer’s office, Ritschard Dam is in the category ‘of dams with significant issues’ and is on ‘an abnormal trend,'” Mahoney wrote.

    Ritschard Dam is 122 feet tall,  1,910 feet wide, and sits across Muddy Creek, which flows into the Colorado River east of Gore Canyon. It was built for the River District in 1995 at a cost of $42 million by D.H. Blattner and Sons of Minnesota.

    The dam has an impermeable clay core that is covered on both the upstream and downstream sides with rock fill, including shale rock excavated on site during construction.

    In 2008, engineers working for the river district noticed the dam had settled downward by a foot-and-a-half, instead of the expected normal settling of one foot.

    They decided to install monitoring equipment, including inclinometers, which measure slope angles.

    Engineers for the river district have since installed an increasingly sophisticated array of monitoring devices. And they’ve verified that the dam has settled over 2 feet downward.

    The dam has also moved horizontally, by 8 inches, at a location about 40 to 50 feet from the top of the dam.

    Mike May, an engineer with AECOM, told the river district board in January 2015 that because of “poorly compacted rock fill,” the dam’s rocky outer shells are still moving, especially the downstream shell, and that the clay core of the dam, which is somewhat elastic, is also moving.

    While the dam does not have “a global stability problem,” May said the concern is that if enough movement occurs, it could cause cracks in the clay core.

    Water could then find its way into those cracks, start transporting material and widening the cracks, and the dam could eventually be at risk of failing.

    Ritschard Dam, which creates Wolford Reservoir on Muddy Creek north of Kremmling, is moving slightly, but steadily. The Colorado River District expects rehabilitation of he dam to be expensive.
    Ritschard Dam, which creates Wolford Reservoir on Muddy Creek north of Kremmling, is moving slightly but steadily. The Colorado River District expects rehabilitation of the dam to be expensive.

    Abnormal behavior

    McCormick, in his April 27 letter referenced by Mahoney, also included Denver Water as part of the risk assessment group.

    “At the conclusion of the meeting it was the opinion of the participants, CRD, AECOM, risk analysis consultants John Smart and Larry Von Thun, Colorado Dam Safety and Denver Water that the risk of sudden failure of the dam by any of the failure modes analyzed was remote,” McCormick wrote. “It was also agreed that given that determination the need to continue to actively pursue physical modifications to the dam was not warranted at this time.”

    McCormick also said that the results of the risk analysis session “now allow the Colorado River District and Colorado Dam Safety Branch to return to more normal reservoir operations with confidence that public safety is not being compromised.”

    However, McCormick also noted that “due to the remaining uncertainty of the deformation behavior we agreed that Ritschard can only be classified as ‘conditionally satisfactory’ and that continuing action with respect to monitoring and observations is required by Colorado River District to operate the reservoir as planned.”

    In his letter, McCormick cited a presentation at the risk workshop by Dr. Gavin Hunter, a professor at the University of New South Wales who has researched deformation behavior in 130 embankment dams.

    Gavin compared the magnitude of the settlement observed at Ritschard dam with other dams in his data set.

    “The displacement observed at Ritschard exceeds the majority of the dams studied, with only half the available data,” McCormick wrote. “Dr. Hunter describes this as ‘an abnormal trend.'”

    McCormick also noted that Gavin’s research on the amount of settlement at Ritschard put it in the “region of dams with significant issues” category.

    As such, McCormick said the River District should develop a plan for remediation work on the dam.

    “We would encourage the Colorado River District to fully appreciate the abnormal and as yet not fully understood behavior of Ritschard dam and put an appropriate timeline on the ‘foreseeable future,’ McCormick wrote. “Based on the analyses done to date one could reasonably anticipate that remediation work will be necessary at some point in the future. We strongly encourage the Colorado River District to continue to plan for such remediation to avoid undue pressure on the operation of that facility as might be caused by a sudden change in the dam’s performance.”

    McCormick said Friday that a workshop to develop an “action plan” has been set for the third week of August.

    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.

    Long odds

    In his April 4 memo, Currier of the River District had written that the district’s analysis indicated that risk of failure of the dam from deformation was 1 in 100 million, while the risk of the dam failing by a “probable maximum flood” causing overtopping – a standard measure of risk – was one in a million.

    He also explained why monitoring the dam’s movement was a better approach than trying to stop the dam from moving.

    “With the dam failure risk so low, even with twice the current deformation, the estimators concluded that there is really no compelling technical or health, safety and welfare reason to embark on a remediation plan,” Currier wrote. “In fact, from a ‘do no harm’ perspective continued monitoring is equally if not more preferable to active remediation.

    “While remediation might put to rest some nagging uneasiness about on-going deformation and when it might end, there is no absolute certainty that it would or should allay that uneasiness.

    “In essence, remediation might replace one known uncertainty with a new, unknown, uncertainty. All dam owners are faced with some level of future uncertainty, we just happen to be keenly aware of it by virtue of extensive monitoring and investigation,” Currier wrote.

    And in his July 7 memo sent to the River District board, Currier said an additional inclinometer has recently been installed at the toe of the dam to track movement, and that he would be sending Mahoney of Denver Water “a short response clarifying a few matters and inviting Denver’s continued involvement and expertise in the deformation issues.”