Aspen officials hesitant to respond to court-raised issues about potential dams

The site of the potential Maroon Creek Reservoir, just below the confluence of East and West Maroon creeks.

A water court referee has advised the city of Aspen it must provide “substantive” responses to issues raised by the division engineer and the court before she issues a ruling in two water court cases tied to the potential Maroon and Castle creek dams and reservoirs.

The issues raised include whether the city can get a permit for the dams, if it can build the dams in reasonable time, if it has a specific plan to build them, and if it needs the water.

The referee, Susan Ryan, wants the city’s responses to those outstanding questions, even if the city reaches a settlement agreement with the 10 parties currently opposing the city’s applications.

“Regarding the response to the summary of consultation, I think it would be useful to see a substantive response prior to the next status conference in this case,” Ryan said at the start of an Aug. 10 status conference on the two cases.

But Cindy Covell, the water attorney for the city, said the city does not want to make its case to the court at this stage of the proceedings.

“Obviously the reason this case is so highly opposed, among other reasons, is that there is a lot of people who think we can’t meet the burden of proof, and that would be the subject of the trial,” Covell said in response to Ryan. “And to the extent that we are putting our case out there ahead of time, it just may make it that much harder to reach a settlement from Aspen’s standpoint, because we know it is a difficult case.”

On July 19 the city issued a statement saying it was seeking “a way to transfer decreed storage rights to locations other than the decreed locations on Castle Creek and Maroon Creek.”

Maroon Creek Reservoir would hold 4,567 acre-feet of water on 85 acres of land, all owned by the USFS. It also would encroach on portions of the Maroon Bells-Snowmass Wilderness. Castle Creek Reservoir, as currently decreed, would hold 9,062 acre-feet on 120 acres of mostly private, high-end residential property, but also flood some USFS land and cross the wilderness boundary.

The city has maintained conditional water-storage rights for both reservoirs since 1965.

“To the extent that you feel that the summary of consultation is asking you to lay out all your evidence, I don’t really see that it is,” Ryan told Covell during the status conference. “I think it is more asking to make sure we have something in the record to support that you’ve met your burden of proof here, before any ruling is entered.”

As water court referee, Ryan’s also charged with investigating the factual and legal aspects of water rights applications before making a ruling.

The issues facing the city were raised in two summaries of consultation that Alan Martellaro, the division engineer, filed with the water court in January after consulting with Ryan about the city’s applications.

Both summaries of consultation filed in response to the Castle and Maroon applications said the city “must demonstrate that it will secure permits and land-use approvals that are necessary to apply the subject water rights to beneficial use.”

They said the city must show that it “will complete the appropriations within a reasonable time” and that “a specific plan is in place to develop the subject water rights.”

They also said the city “must demonstrate substantiated population growth in order to justify the continued need for these water rights” and that it must show it is “not speculating with the subject water rights.”

The U.S. Forest Service, one of 10 parties opposing the city in water court, has told the court it cannot issue a permit for the reservoirs, and so the city cannot complete the reservoirs in a reasonable time. Pitkin County, another opposer, told the court the city has not demonstrated it needs the water and that the city appears to be speculating.

The summaries of consultation required a response from the city to the court, and on July 10, the city submitted only a limited response.

During the Aug. 10 status conference, Ryan told Covell she did not find Aspen’s answers in July to the summaries of consultation “substantive.”

“We’re not trying to play hide the ball here,” Covell then told Ryan, “but a lot of those questions were legal questions, basically asking the city to put out the evidence it is going to use to prove its case at trial, and we just don’t think that’s an appropriate use of the summary of consultation process.”

But Ryan, the water court referee, disagreed.

“I think the purpose of the summary of consultation is to make sure the applicant can support any ruling that is entered in this case. And here the issues raised in the summary of consultation were ‘can and will’ — can the applicant develop this water right within a reasonable amount of time?” Ryan said. “And I do think that is something that needs to be in the record before I can enter any ruling in this case.”

If Ryan is dissatisfied with the city’s responses, she could issue a ruling denying the city’s applications. And the city could then appeal her ruling and take the case to trial before a water court judge. Ryan also can accept the city’s responses and issue a ruling that would maintain the city’s water rights for another six years.

During the Aug. 10 status conference, Ryan agreed to give the city more time (90 days) to respond to the issues raised in the summaries of consultation. The next status conference is set for Nov. 9.

Sometime after that, the city will need to file a substantive response, Ryan said.

Editor’s note: Aspen Journalism is collaborating with The Aspen Times on coverage of water and rivers. The Times published this story online on Wednesday, Aug. 23, 2017.

Aspen puts forward settlement proposals for Maroon and Castle creek dams

This meadow, about two miles below Maroon Lake, would be covered by the potential Maroon Creek Reservoir. The 85-acre reservoir would also flood portions of the Maroon Bells -Snowmass Wilderness.

The city of Aspen has told opposing parties in two water court cases it is willing to remove the prospect of a potential Maroon Creek Reservoir from the Maroon Creek valley, if the way is made clear for it to apply to transfer the conditional water rights for the reservoir to other sites in the Roaring Fork River valley.

The city’s proposal requires the parties to let the city’s periodic diligence applications proceed unopposed, and to also agree not to challenge the city’s efforts to transfer the water rights in new cases, according to several attorneys for opposing parties who attended a city-hosted settlement meeting Wednesday.

And, the city said, even if it’s not successful in those cases, it won’t return and try to store water in the current location of the potential Maroon Creek Reservoir.

“We had a great meeting with the city yesterday and we’re very encouraged that we’ll be able to settle the Larsen family’s opposition on the Maroon Creek Reservoir by the end of the year,” said Craig Corona, a water attorney in Aspen representing Larsen Family LP, which is only in the Maroon Creek case in water court.

Aspen City Attorney Jim True said Thursday that “potential resolutions of the cases were discussed” at the meeting. He was there along with other Aspen officials, including City Manager Steve Barwick, Mayor Steve Skadron and Aspen City Councilwoman Ann Mullins.

Representatives or attorneys from nine of the 10 opposing parties were at the closed-door meeting.

The city of Aspen told the opposing parties it wants to transfer the full 4,567 acre-foot conditional storage right in the Maroon Creek Reservoir to other potential sites, including the Aspen golf course, Cozy Point Ranch at Brush Creek Road, an approximately 60-acre site next to the gravel pit in Woody Creek operated by Elam Construction Inc., or the already-excavated gravel pit. (Barwick, during a July 19 press conference, described the city’s general intent to try and transfer the water rights).

Paul Noto is a water attorney representing American Rivers, Colorado Trout Unlimited and the Roaring Fork Land and Cattle Co. in the Maroon Creek case, and the two environmental groups in the Castle Creek case. He said they were “getting closer” to a settlement.

“The proposal on Maroon Creek, we are a lot closer on, because as I understand it, the city is committing to move their water storage right, and therefore the potential to dam the creek, out of Maroon Creek valley forever and always,” he said. “And that’s a good thing.”

A map showing the potential Castle Creek Reservoir. The City of Aspen has agreed not to flood property owned by Simon Pinniger and Mark and Karen Hedstrom, and so the reservoir is expected to be smaller than shown.

Castle Creek proposal

The city’s proposal regarding the 9,062-acre-foot Castle Creek Reservoir is more complex than its proposal for the Maroon Creek Reservoir.

The city said it would be willing to reduce the size of the Castle Creek Reservoir so it does not flood very small portions of the wilderness, as it does under its current decree. It would then move those portions of the water rights out of the Castle Creek valley.

(Since 2010 the city has signed agreements with two other private property owners whose lands would be flooded by the Castle Creek Reservoir. The city agreed not to flood portions of land owned by Simon Pinniger and by Mark and Karen Hedstrom, on the upstream edge of the potential reservoir. “It is expected that this commitment by Aspen will result in a reduction in the volume and surface area of the Castle Creek Reservoir, and Aspen has contracted for a preliminary investigation of the anticipated revised size and volume of the Castle Creek Reservoir,” the city’s due diligence application from Oct. 31 states. As such, it already be the case that the potential reservoir would not encroach on the wilderness).

The city also said it might further reduce the size of the reservoir if that’s consistent with the size of the city’s future water needs, which are not yet determined. It also might move the resulting reservoir off the private land where it is now sited to another unspecified location or locations.

“The city is just not willing yet to make the commitment to move the water right out of the Castle Creek valley forever and always,” Noto said. “They have more work to do and studies to do to be able to be comfortable in making that commitment.”

But the negotiations over Castle Creek could slow down an agreement on Maroon Creek.

“At this point they aren’t willing to commit to settling the Maroon Creek case separately from the Castle Creek case, so there is a bit of a timing issue because we have more work to do on Castle Creek,” Noto said.

A view, looking toward Aspen, of the gravel pit in Woody Creek operated by Elam Construction Inc. The city has put the sage-covered property next to the gravel pit, to the right in the photo, under contract as a potential reservoir site.

Since 1965

As currently decreed, the Maroon Creek Reservoir would be formed by a 155-foot-tall dam that would back up water over 85 acres of USFS land about 2 miles below Maroon Lake and would flood a portion of the Maroon Bells-Snowmass Wilderness.

The Castle Creek Reservoir would require a 170-foot-tall dam across Castle Creek two miles below Ashcroft, mainly on private land, but with some USFS and wilderness land flooded. The surface area of the reservoir would cover 120 acres of land.

The conditional storage rights for the two reservoirs carry a 1971 decree date and were filed by the city in 1965. Since then the city has periodically told the state it still intends to build the two reservoirs someday, if necessary.

In October, the city submitted two due diligence applications for the potential reservoirs in water court. The applications drew opposition from 10 parties, including four landowners, four environmental groups, Pitkin County and the U.S. Forest Service.

“I think the city has done a lot of work in a short time frame since the last meeting, but there is still a lot more work for all the parties to do,” said Rob Harris, an attorney with Western Resource Advocates who is representing WRA and Wilderness Workshop in the two cases. “Frankly, for both of these water rights, neither one is moved out until they are moved out. We can talk about potential alternative solutions, but we’re not through the woods until both water rights are out of these valleys.”

When asked about the city’s proposal on Castle Creek, Harris said WRA was “committed to protecting” both valleys.

“We do genuinely believe that the city’s goal is to protect these valleys and to avoid building dams in them,” Harris also said. “But their goal is also to hang on to as much of their water right as they can feel comfortable hanging on to. And we have to work really hard to make those goals compatible.”

Aspen Journalism is collaborating with The Aspen Times on coverage of water. The Times published this story on Friday, August 4, 2017.

Aspen puts forward proposals to avoid dams on Maroon, Castle creeks — @AspenJournalism

A map provided by the city of Aspen showing the two parcels in Woody Creek it has under contract. The city is investigating the possibility of building a reservoir on the site, as well as looking at the possibility of a reservoir in the neighboring Elam gravel pit.

From Aspen Journalism (Brent Gardner-Smith) via The Aspen Times:

The city of Aspen has told opposing parties in two water court cases it is willing to remove the prospect of a potential Maroon Creek Reservoir from the Maroon Creek valley, if the way is made clear for it to apply to transfer the conditional water rights for the reservoir to other sites in the Roaring Fork River valley.

The city’s proposal requires the parties to let the city’s periodic diligence applications proceed unopposed, and to also agree not to challenge the city’s efforts to transfer the water rights in new cases, according to several attorneys for opposing parties who attended a city-hosted settlement meeting Wednesday.

And, the city said, even if it’s not successful in those cases, it won’t return and try to store water in the current location of the potential Maroon Creek Reservoir.

“We had a great meeting with the city yesterday and we’re very encouraged that we’ll be able to settle the Larsen family’s opposition on the Maroon Creek Reservoir by the end of the year,” said Craig Corona, a water attorney in Aspen representing Larsen Family LP, which is only in the Maroon Creek case in water court.

Aspen City Attorney Jim True said Thursday that “potential resolutions of the cases were discussed” at the meeting. He was there along with other Aspen officials, including City Manager Steve Barwick, Mayor Steve Skadron and Aspen City Councilwoman Ann Mullins.

Representatives or attorneys from nine of the 10 opposing parties were at the closed-door meeting.

Aspen City Council wades into water shortage scenarios

Scenario A, worst-case:

This scenario is intended to represent assumptions with a combined 1 in 100 probability of occurring.
Climate change is at the worst end of consideration, at 6 weeks peak, 50 percent combined flow and ET impacts. Weighted average demand growth rate is 1.2 percent, resulting in a 2065 treated water demand of approximately 6,320 acre-feet. And flow adjustment factors are at their expected values.

Scenario B, no-growth

Climate change is at the worst end of consideration, at 6 weeks peak, 50 percent combined flow and ET impacts. Demand growth rate is zero; current treated water demand of approximately 3,500 acre-feet continues through 2065. And flow adjustment factors are at their expected values.

Scenario C, intervention

Climate change is at the worst end of consideration, at 6 weeks peak, 50 percent combined flow and ET impacts. Demand growth rate is zero, no outdoor usage during shortages; effective treated water demand during shortages is 2,280 acre-feet. And flow adjustment factors are at their expected values.

_

ASPEN – Whether Aspen needs to build a reservoir to meet water demands in 2065 may depend in part on whether it wants to keep irrigating its municipal golf course during an apocalyptic drought.

According to a water attorney and an economist working for the city on a risk analysis of future water shortages, Aspen may find itself unable to meet domestic water demands — including both indoor and outdoor water use — anywhere from two out of 25 years in an optimistic scenario to 19 out of 25 years in a worst-case scenario.

The most optimistic scenario can be achieved, in theory, if the city limits outdoor watering by its customers and also stops diverting water from Castle Creek to irrigate the 148-acre municipal golf course and other nearby open space.

Outdoor water use accounts for about 60 percent of current demand for city water.

The members of the Aspen City Council took a sip of such concepts Monday at a work session on the results of a water demand study.

Aspen Mayor Steve Skadron said he expects the council to now spend “several months” grappling with the city’s future water needs as part of an exercise to identify alternatives to maintaining conditional water rights for two large reservoirs on upper Castle and Maroon creeks.

Aspen trees near the site of the proposed Maroon Creek Reservoir. The City Council has acknowledged the pristine nature of the Maroon Creek location and is openly looking for water storage alternatives, including at the city golf course and Cozy Point Ranch.

Climate wildcard

Monday night, George Oamek, an economist with Headwaters Corp., presented three scenarios from a risk analysis he’s been developing for the city.

He told the council that his model is packed with uncertainties, mainly around the severity of climate change, but also around the amount of flow in Castle and Maroon creeks and the future demand from Aspen’s water customers.

“We’ve got just a tremendous amount of variability in the existing information that gets translated into our analysis,” Oamek said.

“There is so much uncertainty,” concurred council member Ann Mullins.

“Climate change is everything,” Oamek said. “And it’s the thing we know the least about.”

Oamek also said his model includes a 1-in-100 chance that the factors will line up to cause havoc, which he said is a common risk assumption for municipal water providers and in floodplain mapping with its concept of a “100-year-flood.”

“Frankly, water planners are risk adverse,” he said.

In Oamek’s “worst-case” scenario, runoff would come six weeks earlier in the spring and there would be half as much water flowing in Castle and Maroon creeks, the city’s primary sources of water.

The city of Aspen’s diversion structure on Castle Creek.

Water rights portfolio

The city owns two large senior diversion rights on Castle Creek tied to the historic Castle Creek-Midland Flume. The city has an 1892 decree allowing it to divert 60 cfs. On top of that, it has another right from 1892 for 100 cfs, giving it the ability to divert 160 cfs from Castle Creek.

The city’s streamwide diversion dam is just downstream of Midnight Mine Road and the water is sent via a pipeline to the city’s water treatment plant on a knoll above Aspen Valley Hospital.

Water from Maroon Creek is also sent via pipeline to the treatment plant and the associated 10 acre-foot Leonard M. Thomas Reservoir, which serves as a forebay to the treatment plant, holding water from both Castle and Maroon creeks.

The city owns a 3.4 cfs diversion right on Maroon Creek with an 1893 decree date and another 65 cfs diversion right with a 1949 decree date that, notably, includes an 1892 appropriation date. The city’s streamwide diversion dam on Maroon Creek is located at the T-Lazy-7 Ranch.

The water rights from Castle and Maroon creeks give the city a portfolio of “paper” rights adding up to 228.4 cfs, which is a much larger amount than the city runs through its water treatment plant, even in dry, high-demand, years.

According to a water availability study from Wilson Water adopted by the city in June 2016 as a planning document, the city in the last big drought year of 2012 brought between 2.38 and 9.4 cfs of water into its water treatment plan from Thomas Reservoir. The peak intake of 9.4 cfs was in June.

The city’s pipeline from the Castle Creek diversion limits the amount of water that can be sent from Castle Creek to the treatment plant to 25 cfs and the pipeline from Maroon Creek can move up to 27 cfs.

The city’s diversion rights are separate from its two conditional water storage rights higher on Castle and Maroon creeks.

Those rights, as currently decreed with a 1971 date, are for storing 4,567 acre-feet of water just below the confluence of East and West Maroon creeks in the Maroon Creek Reservoir, and for storing 9,062 acre-feet of water in the Castle Creek Reservoir two miles below Ashcroft.

The combined storage capacity of the potential reservoirs, as currently decreed, is 13,629 acre-feet. The reservoirs, notably, would be located above the city’s two downstream diversion dams.

And both the city’s diversion rights and its conditional storage rights are separate from rights it owns in three irrigation ditches on Castle Creek, downstream from its diversion dam. The headgates for the three ditches on Castle Creek are near the Marolt housing complex.

The city calculates the instream flow at a location below the headgate of the Marolt Ditch, as it is the lowest of the three ditches.

The city of Aspen's Leonard M. Thomas Reservoir, next to the city's water treatment plan, can hold water from both Castle and Maroon creeks.
The city of Aspen’s Leonard M. Thomas Reservoir, next to the city’s water treatment plant, can hold water from both Castle and Maroon creeks.

Supply down, demand up

In his presentation to the City Council, Oamek said his worst-case scenario assumes that demand for treated water would be 6,320 acre-feet of water a year, up from about 3,500 acre-feet today.

The assumption includes a negligible 0.4 percent growth rate in the permanent population in Aspen’s water service area, and a 2 percent growth rate for the part-time population and commercial sector.

That assumption does seem to run counter to Aspen’s past ability, and plans, to lower water demands while the population rises, which may be why the three scenarios also include a no-growth-in-demand scenario, where demand is held flat at current levels, regardless of potential population growth.

For example, a 2014 water efficiency plan from Element Consulting and WaterDM projects the city will, by 2035, “reduce treated demand by about 583 AF — an overall 14 percent reduction in demand.”

And the city has been making solid progress on reducing water demand. In 2012, city staffers told the council the city had reduced water consumption by “over two-thirds over the last 19 years.”

But the water efficiency plan does raise a cautionary note about the city’s lack of storage.

“On an annual basis, the dry year yield of the City’s water rights appears to be more than sufficient to meet current and forecast future demands,” the plan says. “However, the city does not have storage to regulate the timing of supply to match demands, and therefore is vulnerable to peak demand shortfalls in dry years when physical streamflow conditions are limited, or in emergencies such as a fire or landslide when one or more particular water supply sources may become unavailable.”

A graphic in Aspen's draft water efficiency plan shows that the city has generally been using less water over time.
A graphic in Aspen’s draft water efficiency plan shows that the city has generally been using less water over time.

Setting aside the downward demand trend, the most draconian scenario developed by Oamek assumes a near doubling of demand in a much hotter and drier world.

And it shows the city might not be able to meet all municipal water demands — including both indoor and outdoor use — in 19 of 25 years.

“There are frequent shortages for Aspen’s potable supply during that period,” Oamek said.

In 15 of those years, water shortages could be greater than 100 acre-feet of water.

In four of those years, water shortages could be greater than 1,000 acre-feet.

And in one of those years — think the drought year of 1977 — shortages could be greater than 2,000 acre-feet.

“Over 1,000 acre-feet … that would definitely cause some hardship,” Oamek said. “A lot of these shortages, they are not occurring during the irrigation season, or during the summer where you might be able to reduce outdoor use, or work some deals with the irrigators.

“The shortages are occurring kind of in the shoulder season, occurring in late summer, early fall, and also during the winter. And those shortages may be a little harder to mitigate through the utilization of outdoor sources.”

The well-watered Aspen golf course, which sits between Castle and Maroon creeks.

No outdoor watering

The picture gets brighter in Oamek’s “intervention scenario,” the least demanding of the three scenarios.

Runoff would still come six weeks earlier, and there would still be half as much water flowing down Castle and Maroon creeks.

But demand for city water is projected at 2,280 acre-feet a year, as the scenario assumes the city will curtail the use of treated waters for outdoor purposes during a drought.

“During times of shortages, we set outdoor usages to zero,” Oamek told the council, explaining that would drop annual demand in the model to about 2,200 acre-feet, down from 3,500 acre-feet.

In that scenario, there might be 14 years out of 25 when there are water shortages, but only in five of those years would the shortages be over 100 acre-feet, and none would produce shortages over 1,000 acre-feet.

One of the city’s irrigation ditches that carries water from Castle Creek toward the city’s golf course.

No ditch water

Cindy Covell, the city’s water attorney with Alperstein and Covell, then told the council she asked Oamek — the day of the council work session — to run another scenario where the city also stopped diverting water it controls into three irrigation ditches on lower Castle Creek, downstream of the city’s diversion dam to its treatment plant.

“I was thinking, if you were going to run a scenario that involved no outdoor irrigation – you’re telling your customers they can’t water their lawns – you probably are going to have a hard time taking irrigation water down those ditches and irrigating your golf courses and your parks,” Covell said.

Oamek ran a calculation — not a full model run — and said curtailing irrigation drove the number of years with indoor water shortages down to just two years out of 25, and in only one of those years was the shortage greater than 100 acre-feet.

In 2012, the city diverted up to a total of 20.5 cfs into the three Castle Creek irrigation ditches, with the highest diversion rate in June, according to the Wilson Water study.

The city has diversion rights in the Holden Ditch of 25.9 cfs with a 1952 decree, in the Marolt Ditch of 13.6 cfs with a 1934 decree, and in the Si Johnson Ditch of 2.55 cfs with a 1936 decree, according to an agreement with the Colorado Water Conservation Board. That adds up to a “paper” portfolio of 42.05 cfs worth of irrigation rights.

“To some extent you already have a bucket of water, which is the downstream irrigation ditches,” said water attorney Paul Noto, who represents three clients opposing the city’s conditional storage rights in water court, and was asked to comment at the work session by the mayor.

“Tonight we talked about what’s the worst-case scenario, [and] might I suggest that we look at priority irrigation under those ditches,” Noto said. “So perhaps we say, at the golf course we want to keep our fairways and greens green, but maybe we don’t irrigate the rough if the streamflows are below x.”

Noto also pointed out to the council that almost all of their municipal water comes from Castle Creek, and that the water in Maroon Creek is now primarily diverted to power the city’s small hydropower plant on the banks of Maroon Creek.

Maroon Creek, below the diversion, at about 12 cfs during a minimum stream flow demonstration in 2011.

Maintaining instream flows

Maintaining instream flows is a challenge in each of the scenarios presented, as there are dry years when it’s hard for the city to reach its goal of leaving enough water in Castle and Maroon creeks to maintain the environmental flows while also meeting all municipal water demands.

“Worst-case, maximum growth, there is a lot of damage to the instream flows,” Oamek said, noting the annual instream-flow shortages were over 10,000 acre-feet in the worst year in the model.

The city has a policy of maintaining minimum, or instream, environmental flows in Castle and Maroon Creeks.

The Colorado Water Conservation Board holds an instream flow right in Castle Creek for 12 cfs and a right in Maroon Creek for 14 cfs. The state defines that level of flow as the amount of water needed to protect the environment “to a reasonable degree.”

Both of the CWCB’s instream flow rights are junior to the city’s senior diversion rights on Maroon and Castle creeks.

The city, based on the recommendation of a consulting biologist, recently increased its minimum flow target on Castle Creek to 13.3 cfs. As such, the combined minimum instream flow level in Castle and Maroon creeks that the city seeks to maintain is 27.3 cfs.

The city’s policy of voluntarily honoring the state’s junior instream flow rights is centered on a 1997 agreement with the CWCB to protect 12 cfs of flow on Castle Creek. The agreement does not technically extend to Maroon Creek, although the city’s stated policy does.

However, the agreement with the state also includes a provision that allows the city to exempt itself from the policy during periods of “extraordinary drought,” which are not defined.

The provision gives the city latitude to meet its municipal demands and “invade,” as Oamek put it, the junior minimum instream flow rights held by the state, as necessary.

This map from 1984 is one of the few ever published that puts the Maroon and Castle creek reservoirs into the context of the city’s overall water system.

Need a bucket

Staff in the city’s Water Department continue to point out to the City Council that Aspen likely needs some amount of water storage in the future.

“In our integrated water supply system, there are alternatives to storage than can help mitigate our shortages, things like re-use, conservation, ag transfers … but even though these combined can minimize the shortages, storage is still needed because of timing issues,” Margaret Medellin, a utilities portfolio manager for the city told the council Monday night. “To really make these other mechanisms work, we still need a bucket to be able to augment and … re-time the water.”

That message has gotten the attention of Mayor Skadron.

“As we proceed, my goal would be to ensure a sufficient water supply for future generations and to ensure that their options are open,” he said.

He also asked during the meeting, “Does a scenario exist in municipal water planning where storage is not needed beyond just what nature provides?”

“Historically, that’s how Aspen has operated,” Medellin replied. “Aspen has very little storage and has historically operated as a direct-flow water provider. And in areas maybe that are wetter, back East, it is not as problematic.

“And I think the concern is as we are starting to see runoff happening earlier, the demand being extended and happening later into the system … [and] what has worked historically for Aspen, we aren’t convinced is going to work for the next 50 years.

“Even though that it is something that other communities can do, and something that Aspen has done, as we are looking into our models going forward, we’re not convinced that it’s something that is sustainable here,” Medellin said.

However, a 2016 water supply report done by Wilson Water and adopted by the City Council in June of 2016 as a planning document, painted a different picture and found that no storage was necessary – even after factoring in available climate change projections.

The Wilson Water study found that “the results of this analysis indicate the city can always provide sufficient potable and raw water supplies under these modeled demand and hydrology scenarios.

“Existing water supply infrastructure and water rights portfolio developed and managed by the City do not appear to be limiting factors in this evaluation.

“However, during drought periods, physical water supplies may limit the city from satisfying desired ISF (instream flow) bypasses. These modeled ISF deficits are forecasted to occur during drought periods in only the climate scenarios with very low late summer and winter streamflow conditions.

“Most ISF deficits occur at a frequency of 5% of the time or 1 out of 20 years. The predicted average daily ISF deficits are relatively small and can be managed utilizing the existing water supply tools the city has in place and/or is actively developing,” the Wilson Water study said.

And recently completed water-efficiency plans for Basalt, Carbondale, and Glenwood Springs found that those three nearby cities have adequate water supplies for the future without significant storage “buckets.”

A portion of the gravel pit in Woody Creek operated by Elam Construction. It’s hard to capture the scale of the gravel pit, but the little yellow speck in the back edge of the pit is a large dump truck.

Shortage into storage

Medellin also told the council one of the next steps is to convert the shortage numbers from the Headwaters risk analysis to potential storage numbers.

“It’s not a one-to-one conversion,” Medellin said, noting that the storage figure is always larger than the shortage number.

She said a “reservoir operations model” will be used to “apply a reservoir efficiency factor to account for losses and reservoir integrity.”

“What that means is all of the water that we put into a reservoir, we’re not going to get that back out,” she said. “So there is a factor that is commonly added to account for that. Then the next step is going to be to determine what volume of conditional storage rights we need to satisfy that requirement.”

Covell, the city’s water attorney, further explained the process.

“You look at your streamflows, and you say, how often can I fill up this reservoir?” she said. “And on the eastern slope, you might not be able to fill it up more than once every five years. So you say, if I need to be sure I’ve got to have 100 acre-feet of water in storage, I might have to fill up 600 acre-feet, because when I need that 100 acre-feet some of the water will have evaporated and I won’t be able to top it off again because my water right won’t be available.

“And that’s a, maybe, overly simplistic example, but when you’re trying to figure how much storage capacity you need, you have to figure out when you are going to be able to put water in, how much of it’s going to evaporate, and when you’re going to need to take it back out,” Covell said.

Medellin added that the engineering firm Deere and Ault of Longmont is now making calculations for both in-situ and surface water reservoirs, and the storage needs will be based on the representative period of years in the model being used by Headwaters.

The property next to the Elam gravel pit and the Woody Creek raceway that the city of Aspen has put under contract. The city is investigating the site as a place for potential water storage, either underground or above ground.

Settlement talks

It’s not clear yet how the scenarios presented Monday may change the city’s negotiating position with the 10 parties opposing its ongoing efforts in water court to maintain conditional water storage rights for reservoirs on Castle and Maroon creeks.

Last week, the city announced it now intends to transfer its water rights from Castle and Maroon creeks to two potential reservoir sites in Woody Creek, including on land it now has under contract near the Elam gravel pit, and the gravel pit itself.

“The impetus for the purchase is to seek a way to transfer decreed storage rights to locations other than the decreed locations on Castle Creek and Maroon Creek,” the city said in a July 19 press release titled “Aspen City Council to Purchase Land for Possible Alternate Site for Water Storage.”

“Since 1965, the city has held decreed water storage rights at sites in Maroon and Castle Creek Valleys but the nature of these pristine locations has made it a priority for the city to first seek other ways to address potential water shortages and to seek alternate locations for water storage,” the city stated.

And Skadron was quoted in the release as saying “securing Aspen’s water future is an essential task of today’s city council. It is council’s responsibility to look out for the welfare, safety, and health of the community and we take that very seriously. In addition, our commitment to protecting our environment is also a priority and this land purchase is a way to both protect the community and preserve Castle and Maroon valley wild lands.”

The city also said in the press release about the Woody Creek options that “other alternatives for water storage are still being explored, including in-situ reservoirs at the Aspen Golf Course, Cozy Point Ranch, the portion of the city-owned Maroon Creek golf course, and other upper valley locations.”

A second settlement conference with the opposing parties in the two water court cases is set for Aug. 2 and a status conference with the water court referee is Aug. 8.

Editor’s note: Aspen Journalism is collaborating with The Aspen Times on coverage of rivers and water. The Times published a version of this story on July 25, 2017.

Aspen plans to transfer Castle and Maroon creeks conditional water rights to other locations — @AspenJournalism

The property next to the Elam gravel pit and the Woody Creek raceway that the City of Aspen has put under contract. The city is investigating the site as a place for potential water storage, either underground or above ground.

From Aspen Journalism (Brent Gardner-Smith):

Aspen city officials said Wednesday they plan to seek water court approval to transfer the city’s two conditional water rights to store a combined 13,629 acre-feet of water in upper Castle and Maroon creeks to other potential storage locations in the Roaring Fork River valley.

Those locations include 63 acres of land it has under contract to purchase for $2.65 million on Raceway Drive in Woody Creek, a neighboring gravel pit operated by Elam Construction Inc., the city’s golf course, portions of the Maroon Creek Club golf course owned by the city, and Cozy Point Ranch.

Aspen City Manager Steve Barwick said at a news conference the city is not walking away from its conditional water rights tied to the potential dams and reservoirs on Castle and Maroon creeks, but instead is holding on to those rights while seeking to transfer them, and their 1971 decree date, to new locations.

“We’re going to attempt to transfer the water rights down to these sites,” Barwick said. “There would not be any abandoning of water rights. It would be moving the water rights from one site to another.”

To do so, the city would have to file a new water rights application in water court and it would be up to a water court judge to determine how much of the current water rights could be transferred, and if the city can keep the 1971 decree date.

In October, the city filed two due-diligence applications for its conditional rights on Castle and Maroon creeks and is now being opposed by 10 parties.

The potential Castle Creek Reservoir would store 9,062 acre-feet of water behind a 170-foot-tall dam and the Maroon Creek Reservoir would store 4,567 acre-feet behind a 155-foot-tall dam within view of the Maroon Bells.

The city expects to put forward a settlement offer to the opposing parties next week, with the potential Woody Creek storage sites at the heart of the offer, Barwick said. A settlement meeting is slated for Aug. 2.

Paul Noto, a water attorney representing American Rivers, Colorado Trout Unlimited, and the Roaring Fork Land and Cattle Co. in the two water court cases, said Wednesday a “main issue” for his clients is whether the city will commit to “never damming” Castle and Maroon creeks.

A news release issued Wednesday by the city quoted Aspen Mayor Steve Skadron as saying the pending Woody Creek land purchase “is a way to both protect the community and preserve Castle and Maroon valley wild lands.”

Both of the dams, which the city has told the state since 1965 it intends to build someday, if necessary, would inundate portions of the Maroon Bells-Snowmass Wilderness.

“While the Castle and Maroon Creek reservoirs may have seemed like a good idea (in the 1960s), we congratulate the city for this win-win alternative that protects our iconic landscape and provides for the city’s water needs,” said Sloan Shoemaker, the executive director of Wilderness Workshop, in a press release.

(Above is audio of a press conference held at Aspen city hall on Wednesday, July 19, 2017. The audio was recorded by Elizabeth Stewart-Severy of Aspen Public Radio. The main speaker is Aspen City Manager Steve Barwick. Also present at the press conference were Curtis Wackerle, editor of the Aspen Daily News, David Krauss, editor of The Aspen Times, Elizabeth Stewart-Severy, environment reporter at Aspen Public Radio, and city staff members David Hornbacher, Margaret Medellin and Mitzi Rapkin. Aspen city council member Bert Myrin was also in the room, but did not speak. Brent Gardner-Smith of Aspen Journalism can be heard asking questions via a phone on the table in the room.).

A map provided by the city of Aspen showing the two parcels in Woody Creek it has under contract. The city is investigating the possibility of building a reservoir on the site, as well as looking at the possibility of a reservoir in the neighboring Elam gravel pit.

Woody Creek options

The two Woody Creek parcels now under contract by the city include a 61-acre parcel and a 1.8-acre parcel. Both are owned by Woody Creek Development Co. of Fort Collins.

The undeveloped 61-acre parcel is valued at $2.3 million by the county assessor and the 1.8-acre parcel, also undeveloped, is valued at $100,000.

The city does not have an option to purchase the Elam gravel pit, which is visible from Highway 82, but is in discussions with the company about opportunities.

“We are interested in working with the city on its water storage project,” Russell Larsen, the chief operating officer of Elam, was quoted as saying in the news release. “There are benefits for both entities. The city can assist us with reclamation of the property into the future and we are eager to explore ways we can support Aspen’s water storage needs.”

The city also said it is researching “the environmental, hydrologic and geologic nature” of the two Woody Creek parcels, and Barwick said he expects the City Council to make a decision to purchase the land within 90 days.

The city will be studying the 63 acres for the potential to develop both above-ground storage and in-situ, or underground, storage. And Barwick said the gravel pit may present the best potential to build an above-ground reservoir, “since there is already a pit there.”

If reservoirs were developed in any of the potential locations, the stored water – if used to meet municipal water demands – would have to be pumped back up to the city’s water treatment plant, which sits on a hill behind Aspen Valley Hospital.

“Worst-case scenario, you pump water into them and then pump water back up,” Barwick said. “We would prefer someday to create a gravity-fed storage system.”

He also said the Aspen City Council must figure out how much water the city may need to store in the future. A second work session on the topic has been set for Monday evening.

A portion of the gravel pit in Woody Creek operated by Elam Construction. It’s hard to capture the scale of the gravel pit, but the little yellow speck in the back edge of the pit is a large dump truck.

Praise from opponents

Officials from Western Resource Advocates also praised the city’s announcement.

“We’re pretty encouraged,” said Rob Harris, a senior staff attorney at Western Resource Advocates. “We’re not at the destination yet, but if you want to reach a different destination, the first concept is to change course, and it seems like the city has done that today.”

But in a news release Western Resource Advocates also included a cautionary note.

“The city’s announcement does not, in itself, end the pending water court cases considering the city’s conditional water rights,” the release said. “The city’s press release makes clear that its willingness to entirely drop the Maroon and Castle creeks dams from its water rights portfolio has preconditions.”

Noto, the water attorney for three clients in the cases, said the city’s announcement was “potentially a step in the right direction. I appreciate the fact that they are looking hard at alternatives.”

When asked about the city’s intention to try to transfer the 1971 decree date of the Castle and Maroon rights, Noto pointed out if they were successful, those rights would then be senior to the instream flow rights held on the Roaring Fork River by the Colorado Water Conservation Board and the recreational in-channel diversion rights held by Pitkin County in its new kayak park in Basalt.

“They would be jumping ahead, essentially, of two large water rights, and I’m sure that will be cause for concern,” he said.

Editor’s note: Aspen Journalism is collaborating with The Aspen Times on coverage of rivers and water. The Times published this story online on July 19 and published it in its printed edition on July 20, 2017.

Aspen changing course on conditional water rights?

The Maroon Bells from the meadow just above the confluence of East and West Maroon creeks, and the location of the potential Maroon Creek Reservoir.

ASPEN – Aspen city officials plan to reveal this week a proposal that seeks to resolve some of the issues raised by its efforts to maintain conditional water storage rights tied to potential dams and reservoirs on upper Castle and Maroon creeks.

Last week the city approved money to study underground storage, looked into how much water storage it needs, and responded in water court to a previous filing. In the past month, city officials also have met with a number of opponents in the water case.

“Things are changing rather quickly regarding the current diligence cases,” Aspen City Manager Steve Barwick said Friday, referring to the two ongoing due diligence cases now unfolding in Division 5 water court. “I expect a completely different discussion will be taking place within one week.”

Barwick also said he and other city staff members “have a great deal of work to do toward that outcome” and he expects to hold a news conference by Friday about the city’s proposal.

As presently decreed, the Maroon Creek Reservoir would store 4,567 acre-feet of water behind a 155-foot-tall dam a mile and a half below Maroon Lake. The Castle Creek Reservoir would hold 9,062 acre-feet behind a 170-tall-reservoir on the main stem of Castle Creek 2 miles below Ashcroft.

The city originally filed for the water rights in 1965 and has periodically told the state it intends to build the dams and reservoirs, if necessary, as part of its municipal water system.

The city filed its most recent applications for due diligence Oct. 31 and is seeking to hold on to its conditional rights for another six years.

City officials do not appear to have tipped their hand to the opposing parties in the cases about the substance of this week’s announcements.

“I really don’t know what the city will present at its big announcement,” said Rob Harris, senior staff attorney at Western Resource Advocates, who recently met with city officials on potential alternatives to the reservoirs, along with a representative from Wilderness Workshop of Carbondale. “I’m assuming that this will be more in the nature of the city announcing its preferred solution, or some part thereof, rather than any sort of finalized deal with any of the parties.

“Whatever they present, the follow-up questions we’re going to be asking include whether their idea moves Castle and Maroon creeks upstream of Aspen closer to permanent protection and, if their idea involves moving any or all of the water rights, what the potential impacts and benefits of that change will be,” Harris said.

The environmental organizations opposing the city in water court also include Colorado Trout Unlimited and American Rivers.

“What would not make us happy is if they said, ‘We will significantly downsize these reservoirs but keep them in the same place,'” said Matt Rice, director of American River’s Colorado River basin program, during an interview in late June. “We’re hopeful they are coming around to the impossibility of developing those projects in the two valleys, and what that means for this diligence, and that they are getting realistic about more-appropriately sized projects that can help them meet their water supply needs.”

Rice also said that Aspen Mayor Steve Skadron met with Bob Irvin, the president and CEO of American Rivers, on June 21 at city hall for 45 minutes.

“It was an opportunity to extend an olive branch of sorts and commit to working toward a resolution to this issue in good faith,” said Rice.

The city has scheduled a second settlement conference for Aug. 2 with the 10 opposing parties in the water rights cases.

A view of the Aspen municipal golf course from Red Butte. A consulting engineer for the city of Aspen has found that an ‘in-situ’ reservoir could likely be built to store water under the golf course, which sits on about 75 feet of glacially-deposited rock and gravel. A trench filled in with a clay-like material could be dug around the perimeter of the golf course and water could be poured into the open space in the remaining gravel, and pumped back out as necessary.

Golf course option?

On Monday the city council approved a $116,000 contract with the engineering firm of Deere and Ault of Longmont to drill test bores and dig exploratory pits on the course at the Aspen Golf Club as part of a feasibility study of an in-situ, or underground reservoir.

Such an “in-situ” reservoir would likely hold about 1,200 acre-feet of water, according to a preliminary investigation done by Deere and Ault.

Deere and Ault now plans to drill up to six test bores through what is estimated to be 75-feet of gravel under the golf course, and to dig up to eight pits, of undisclosed size, to analyze the soil and gravel conditions.

City Engineer Trish Aragon said this week that a construction management plan will be required by the city’s engineering department for any drilling work that goes deeper than 50 feet.

And a permit would be required if the excavation pits disturb more than 200 square feet of surface area.

Aragon, after checking with officials at the city’s water department, said it has not yet been determined when, or where, the drilling or digging will take place.

The members of the Aspen City Council on Monday, July 10, 2017. From left, Bert Myrin, Ward Hauenstein, Mayor Steve Skadron, Ann Mullins, and Adam Frisch.

In water court

On the same day the city council approved further investigations on the golf course, the city’s water attorney, Cindy Covell of Alperstein and Covell in Denver, submitted a required response to a “summary of consultation” report filed by the division engineer in Division 5, Alan Martellaro, on January 23.

In a July 10 letter Covell told Materellaro that Aspen “understands that it must meet the required burden of proof at trial,” but otherwise she left the concerns of the state officials unaddressed.

The report, prepared after consulting with water referee Susan Ryan, challenged the core of Aspen’s applications for the dam and reservoir rights.

“I cannot recommend approval of this application until the following concerns are addressed,” Martello’s report began, in a standard opening line for such reports.

The first concern cited was about the phrase “other beneficial uses” in the city’s claims to maintain its conditional storage rights, which carry a 1971 decree date.

And the second concern was whether Aspen’s applications meet key tests in a due diligence case.

“Regarding the ‘can and will’ and the ‘anti-speculation’ doctrines,” Martellaro wrote, “the applicant must demonstrate” that it will secure necessary permits and land use approvals, that it will complete the projects “within a reasonable time,” that a “specific plan is in place to develop the subject water rights,” and that the city “is not speculating with the subject water rights.”

The issues raised by the state officials are much the same as those raised by the ten opposing parties in the two cases.

The parties, in addition to the four environmental organizations, include Pitkin County, the United State Forest Service, and four private landowners.

Two of the landowners own property in the Maroon Creek valley, Thomas and Margot Pritzker and Marcella Larsen and her family. And two own property in the Castle Creek valley, Robert Y.C. Ho and Charles Somer.

“I think the division engineer raised some serious concerns that are entirely consistent with ours,” Rice of American Rivers said in late June. “We would appreciate it if they would answer the core questions.”

But the city chose not to do that this week.

The questions raised in the summary of consultation remain open in the case, however, and may be addressed in the future by the water referee or at trial, as Covell suggested.

The location of the potential Maroon Creek dam and reservoir, just below the confluence of East and West Maroon creeks.

Supply and uncertainty

On Tuesday the city council got an update on a risk analysis being conducted by Headwaters Corp. of Nebraska regarding the city’s future water supply and demand equation.

George Oamek, the economist who is preparing the study, submitted a preliminary report to the city on July 3, in an effort to help the city council determine how much will they need in the future and where they should store it.

He told the council that in order to complete his risk analysis, he and the council members are going to have make a number of assumptions about “uncertain variables.”

He said the data recorded by now defunct stream gages on Castle and Maroon creeks from 1970 to 1994 was insufficient for his analysis, although the 24 years of data has been the basis of several other in-depth water supply and demand studies done for the city.

He said that available climate data would be hard to use to predict local conditions.

And he recommended using land use projections in Aspen and Pitkin County to determine future water demand, as opposed to the standard methodology of using population projections.

Oamek also presented a pie chart to the council that illustrated the varying degrees of uncertainty presented by each of those areas.

About 70 percent of the uncertainty, and thus required assumptions, is in the area of climate change, he said, while 20 percent was related to the gaps in the data about flows in the creek, and ten percent was tied to demand projections.

Oamek told the city council members that he was relying on them for assumptions about land use and population.

Margaret Medellin, a utilities portfolio manager for the city, told the council that Tuesday’s meeting on the Headwaters study was not the last.

“This is just the first of many conversations,” she said. “We’ll be coming back to council for quite some time.”

Editor’s note: Aspen Journalism is an independent nonprofit news organization collaborating with The Aspen Times on coverage of rivers and water. The Times published a shorter version of this story on Monday, July 17, 2017.

City of Aspen eyes storing water under golf course in lieu of dams, reservoirs

A view of the Aspen municipal golf course from Red Butte. A consulting engineer for the city of Aspen has found that an 'in-situ' reservoir could likely be built to store water under the golf course, which sits on about 75 feet of glacially-deposited rock and gravel. A trench filled in with a clay-like material could be dug around the perimeter of the golf course and water could be poured into the open space in the remaining gravel, and pumped back out as necessary.

ASPEN – In their ongoing search for alternatives to building dams and reservoirs on Maroon and Castle creeks, Aspen officials continue to explore other options, including an underground reservoir that would store water below the city’s golf course.

Aspen City Council reacted favorably to a presentation in May about an “in-situ” or underground reservoir beneath the Aspen Golf Club, with one council member saying it was a “great introductory lesson.”

Aspen City Manager Steve Barwick said last week there is plenty more work to be done.

“City Council had a lot of questions regarding the viability, impact and cost of in-situ storage,” Barwick said, “and they have not yet even begun their review of the storage needs.”

Barwick also said recently that the city does not know exactly how much water it needs to store to meet future needs, but the council is set to hear a presentation on the subject at a July 11 work session.

“All of this, this whole notion of how much water do we need and how much water do we need to store, and all of that, has been based upon very preliminary analysis,” Barwick told the Pitkin County Healthy Rivers and Streams Board on March 16. “And now it’s time to tighten up the whole analysis and do a rational set of studies so we can have a rational discussion with the entire valley about what are we going to do here. How much storage do we need, and where do we want to put it?”

Loose rock and gravel on the edge of the Aspen golf course, showing a glimpse of what might lie below the surface of the course.

Feasible

Don Deere, a geotechnical engineer who has worked on a long list of water storage projects in Colorado, said during his presentation to the council in May that the city’s golf course has the right combination of bedrock and “terraced gravels” required for an in-situ reservoir, in which claylike walls are built in trenches around a rock-filled area to hold water.

“Engineering-wise, it’s feasible,” Deere confirmed this week in a phone interview. “You’ve got to drill it to know for sure if the site’s going to work, but there are some favorable aspects to that site, for sure.”

The 148-acre public golf course is located between lower Castle and Maroon creeks and sits on top of about 75 feet of gravel and river rock left by retreating Ice Age glaciers, said Deere, who is chairman of the civil engineering firm Deere and Ault Consultants, Inc. in Longmont.

An in-situ reservoir under the golf course could hold about 1,200 acre-feet of water, Deere said, which the city could then pump back up to its water-treatment plant if needed.

By comparison, the city has a 10 acre-foot reservoir at its water-treatment plant, which it says amounts to about a day’s use of water for the city’s water system. For comparison, Ruedi Reservoir holds about 100,000 acre-feet of water. Deere called a 1,200 acre-foot reservoir “a small reservoir.”

A potential 170-foot tall dam near Ashcroft on Castle Creek would create a reservoir that holds 9,062 acre-feet of water; a 155-foot dam on Maroon Creek near the Bells would hold 4,567 acre-feet.

The city applied to Division 5 water court in October to maintain its conditional water rights for the two reservoirs on Maroon and Castle creeks, and is facing opposition from 10 parties, including the U.S. Forest Service and Pitkin County.

Much of the opposition is because of the locations of the potential dams and reservoirs, both of which would inundate portions of the Maroon Bells-Snowmass Wilderness. Some opposers also are questioning whether the city really needs to store nearly 14,000 acre-feet of water.

And as the city tries to answer the “how much” question, they’ve also been looking at the “where” and “how” questions.

A graphic from Wilderness Workshop that shows how the potential Maroon Creek Reservoir would behind a 155-foot-tall dam just below the confluence of East and West Maroon creeks.

Exploring options

A study of the idea of storing water in old silver mines around Aspen was also presented at the May 15 work session by another Deere and Ault engineer, Victor deWolfe III.

He said it likely would be expensive and complicated for the city to use the old mines, especially as it would be difficult to maintain control of the water in the complex maze of old shafts and tunnels.

The in-situ option, by comparison, sounded more feasible.

Deere looked at two potential locations for an in-situ reservoir, both on city-owned property, the golf course and the city’s Cozy Point Ranch property at the intersection of Brush Creek Road and Highway 82.

The Cozy Point has a better combination of gravel and bedrock for an in-situ reservoir than the golf course, Deere said, but most of the focus at the work session was on the golf course site, in part because the city currently delivers water from Castle and Maroon creeks to irrigate the golf course.

A graphic from a paper authored by Don Deere shows how the walls of an in-situ reservoir are formed. The paper is called 'Gravel Pit Reservoirs, Colorado's Water Storage Solution.'

A trench, filled in

Deere told the council a reservoir under the golf course could be built by using a long-armed excavator to dig a 3-foot-wide trench around the course through the estimated 75 feet of gravel and river rock down to a solid layer of bedrock.

The trench, which would encircle the golf course, would be filled in with a claylike substance (a soil-bentonite mix) that would hold water. Deere said under the right conditions, such a deep trench, sometimes called a slurry wall, can be dug and filled back in with the claylike material at the rate of about 100 feet a day.

“In a couple of months, on a typical site, I can have a completely lined vessel,” he said.

City-owned water from Castle and Maroon creeks could then be delivered to new and existing ponds on the golf course and allowed to slowly infiltrate into the spaces between the loose rock left in the vessel.

If the city needed to during a drought, it could then pump the water from the new underground reservoir to its water treatment-plant located on a hill behind Aspen Valley Hospital. It’s about a mile from the center of the golf course to the treatment plant.

Water hazards

Councilwoman Anne Mullins asked Deere if the golf course would look the same after an in-situ reservoir was installed.

“I think we’d need to add some ponds, so there would be more water hazards when we’re done,” Deere said, but other than that, “it’s out of sight, out of mind.” And he said this week that after revegetation, no one would even know the in-situ reservoir was there.

As a general rule, Deere said it costs about $10,000 per acre-foot-of water stored to build an in-situ reservoir ­— if favorable soil conditions allow for the standard use of an excavator. But if conditions such as deeper gravel or harder bedrock require a crane and a platform to be used instead, the cost can go up by a multiple of five or six, he said.

Conceptually then, the construction costs of a 1,200 acre-foot in-situ reservoir could range from $12 million to $72 million, according to Deere.

“But we haven’t done a site specific cost estimate for the golf course,” Deere said this week.

He said it would require drilling test holes to know more about the feasibility and potential cost, as it would reveal the true depth of the gravel and the condition of the underlying bedrock.

In May, city officials told the parties in the water court cases that it expected to finish its study of in-situ storage by July. The next settlement conference in the cases is set for the first week of August.

Editor’s note: Aspen Journalism is collaborating with The Aspen Times, the Glenwood Springs Post Independent, the Vail Daily and the Summit Daily on the coverage of water and rivers. The Times published this story on Monday, July 3, 2017.