A short section of orphan railroad tracks is among the reminders of what came before Denver built one of its more inspired flood-mitigation projects, the 39th Avenue Greenway, in the near-northeast part of town.

So is the auto salvage yard that still sits just over a fence from the walking path.

The greenway, which , nods to the past of Denver’s Cole and Clayton neighborhoods — for decades a mix of industry and working-class homes — even as the area is changing rapidly.

As it unfurls for a mile going east from Franklin Street, the 12-acre linear park is centered around a drainage channel that flows gently, like a small stream. Natural vegetation grows alongside the water, while sometimes-meandering walking paths up the embankment connect a community garden, pedestrian bridges, a plaza with seating, playgrounds and several pieces of public art as the greenway continues on to Steele Street.

All of it is within walking distance of century-old houses, factories and the new high-rise apartment buildings that have gone up in the River North Art District to the west.

Anytime I visit the greenway, usually looping it into one of my morning runs, I marvel at the ways it links the underappreciated history of the neighborhoods to the fast-changing face of urban Denver. Others join me, whether playing fetch with their dogs, going for a walk, pushing a stroller or watching their children play on the inventive playgrounds.

It’s a pocket of calm near the increasing bustle of RiNo, near still-working plants like a Coca-Cola bottler and the Nestle-Purina pet food factory — whose proximity you can, alas, occasionally smell, depending on the wind’s direction — and near schools as well as the resurging York Street Yards business center.

In recent weeks, the greenway’s still-developing vegetation and trees offered unexpected bursts of fall color, too.

I remember how unusual the plans for the 39th Avenue Greenway sounded nearly a decade ago, as I covered the advent of the city’s Platte to Park Hill program as a city government reporter. The roughly $300 million undertaking to reduce street flooding across several neighborhoods attracted tons of heat and pushback. Most of it was focused on higher-profile projects — namely the substantial regrading of City Park Golf Course to create stormwater detention areas — and the program’s side benefits for the then-upcoming Interstate 70 project to the north.

The greenway plan, too, sparked worries about chemicals and other pollutants in the soil. City officials said they’d clean up whatever they found as they ripped up abandoned railroad tracks east of York Street and disturbed other parts of the area’s industrial past.

Now that it’s built, the greenway’s channel usually has some water in it, but it fills up more impressively after storms. The water passes through vaults that capture trash, keeping it out of the South Platte River downstream, and the exposure to sunlight helps remove contaminants. The vegetation helps filter the stream before it disappears back underground at Franklin.

It’s hard to overstate the difference between what seemed, at the time, an underwhelming plan for a dressed-up drainage ditch and the actual reality on the ground. It’s now honest-to-goodness parkland that was well thought out in a part of the city that so desperately needed it.

After covering the controversies around all the stormwater projects and then seeing them built, I didn’t come to appreciate the 39th Avenue Greenway until I moved to Cole a couple years ago from another part of Denver.

I rediscovered it, in a way, on an early exploratory run.

Now I run there most often as part of an out-and-back course, taking in the trees and plants and odd features — like the short stretch of disconnected train tracks that’s there, as a kind of monument to the past, and several pieces of public art.

My favorite is , situated across the channel from each other and positioned to enable people to talk across that distance. Called “Conversation,” the piece draws on the history of discrimination affecting the area, which has been home to some of Denver’s most racially diverse neighborhoods, and is intended to highlight the importance of racial dialogue.

When I turn around to head back west, I look up, taking in Mount Blue Sky and the rest of the Front Range on the horizon as I trot toward the still-emerging RiNo skyline that bookends the other side of the greenway.

Allowing development on land protected by both a conservation easement and recreational zoning is too dangerous a precedent to set, regardless of how amiable the developer is, how direly we need affordable housing, or how many “stakeholder” meetings are held.

Sometimes no means no, and that should be the case every time there is a request to develop land encumbered by a conservation easement. In this case, the city had the foresight in 1997 to pay the owner of a golf course in north Denver $2 million (about $3.2 million in today’s dollars) for a perpetual conservation easement requiring the land be used as a golf course. At the time, it was a win, win. The owner, Clayton Trust, received needed money to continue its charitable mission of providing educational opportunities for a community that has historically been underserved. And the city received assurances that a 155-acre property would remain open space for the benefit of the public — taxpayer dollars, after all, were used to acquire that protection. The goal now should be to demand that the land either be a golf course or that it be sold to the city to become a regional park.

In the past 20 years the relationship between the city and Clayton has become a muddled mess only complicated by two facts: Clayton leased the golf course to a third-party operator, which had substantial rights written into its lease; and early this year the city used its powers of eminent domain to temporarily take 35 acres to build a portion of the Platte to Park Hill flood prevention system. That closed down the golf course and exposed the operator leasing the golf course to financial damages. A lawsuit was filed.

Because of the way the easement was written, the city faced a multi-million dollar financial liability. That liability included paying for lost revenue during construction, paying for the golf course to be restored to working order and, here’s the kicker, potentially losing the easement on the land completely.

Hancock and his team settled that liability with the new owner of the land — Westside Developers Inc. — for $6 million, according to a story in The Denver Post last week, and the easement remains in place.

So now the question is, should the city allow Westside Developers to build on a portion of the open space? It����ap tempting to seek a compromise — give Westside 55 acres in the northeast quadrant for whatever it is they have planned and acquire the remaining 100 acres for a park. And there’s a risk in shooting down such a compromise: an area full of mature trees and maintained grasses could be left to die and run wild while the developer “waits out” the political will of elected officials.

But the developer has acquired this land at an incredible bargain, paying $24 million and receiving an almost immediate $6 million settlement from the city. For comparison, consider that in July, a quarter-acre parking lot sold for $1 million a block north of the northwest corner of the golf course.

Once the city rejects the development of this parcel, the smart move would be for Westside to sell the land back to the city for the initial investment and call it a $6 million victory, rather than engage in a protracted battle with unknowable returns.

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For nearly three years, a community debate has pit open-space advocates against development supporters who want to see housing or other uses allowed on some of the 155 acres in northeast Denver. Now the agreement reached with Westside Investment Partners gives the developer at least three more years to plot out its plans. Westside bought the land for $24 million in July from a trust managed by Clayton Early Learning.

“We have been working hard to get to know the people, the history and the community surrounding this unique property and are looking forward to participating in a city-led, community-driven process to reimagine this land for the future,” Kenneth Ho, who leads the project for Westside, said in a news release.

Westside officials created a website for residents to get updates and find out how they can contribute at .

In the meantime, the settlement will leave in place a city open-space covenant that allows only golf-related uses of the property — giving the city’s elected leaders leverage to shape the conversation and require more public input, officials said.

The deal compensates Westside for the city’s use of the northeast corner of the course this year to add stormwater detention and drainage as part of the wide-scale Platte to Park Hill project, which closed down the course. The money is coming from the land-condemnation fund of that roughly $300 million project.

The deal also ends a lawsuit against the city that was lodged by the golf course’s private operator, Arcis Golf, and taken over by Westside when it bought the property. The sum includes money for Westside to restore the golf course later, if needed. Arcis operated the course under the name Park Hill Golf Club.

“My priorities for the property and for the neighborhood have always been preserving open space and extensive community input. This agreement ensures we will have both,” Mayor Michael Hancock said Tuesday through a spokesperson. “The easement will be preserved while the neighbors who are most impacted by this property will be able to guide its future use.”

Hancock’s office announced the proposed settlement in early October but withheld many details, including the $6 million payment, until it was finalized this week. City attorneys briefed City Council members on the details Tuesday morning but said the council’s approval wasn’t needed because it previously gave the Hancock administration permission to acquire land for the stormwater project.

Expect debate to continue

The prospect of a settlement has done nothing to quell outrage among open-space advocates, including former Mayor Wellington Webb, whose administration was responsible in 1997 for the conservation easement allowing only golf-related uses.

Woody Garnsey, an organizer with Save Open Space Denver, has said his ultimate goal is for the city to buy the land and create a regional park. He views Westside’s community process as a sham to maximize the development potential.

“What they’re going to do is try to wear the public out over the next three years,” he said Tuesday, adding: “This looks like an agreement … (to figure out) a way to circumvent the perpetual open space conservation easement. The taxpayers of Denver already decided how to use this land when they spent $2 million in 1997 to preserve it in its scenic and open condition and for recreational use.”

The open-space covenant can’t be undone without council approval, but SOS Denver to draw attention to a new state law related to oversight of conservation easements. Its leaders say that law will make it more difficult for the city to dissolve the restriction by requiring court action.

City attorneys, however, argue the city still has a “clear legal path” under the new law to terminate the easement.

If that happens, said Ho from Westside, “We think we can do more to meet access, equity, health, open space and environmental stewardship goals for Denver than to restore this land as a golf course.”

Details of settlement

Tuesday’s settlement sets some guardrails for the next three years:

• It preserves the 22-year-old open-space easement for now, but the city can’t force Westside to operate a golf course on the land until after the three years is up. The city and Westside could agree to dissolve the easement sooner than that.
• Westside will have at least that much time to organize a community process to seek input and put together its development plans for the land. It has said it intends to retain some of the open space. Westside needs City Council approval not only to remove the easement but also to change the current open-space zoning to allow any development.
• Westside must secure and maintain the property, including removing trash, mowing grass, pruning trees and controlling weeds. The city will be responsible for maintaining the 25 acres it is using permanently for stormwater management.

The July sale to Westside ended more than a century of control over the land by the George W. Clayton Trust, which in recent decades has been managed by Clayton Early Learning, an education nonprofit. It contracted out the operation of the golf course but said that business wasn’t raising sufficient money for its educational programs.

At one point, the city was set to purchase the course, but that deal fell through in 2017 after Arcis challenged it.

Mayoral spokesperson Theresa Marchetta said if Westside were to fail to win support for its plans, or not put any forward, the city could purchase the land more easily, given the settlement removes the legal entanglements that doomed its previous offer.

Staff writer Saja Hindi contributed to this story.

DOCUMENT: Park Hill Golf Course settlement agreement

The long-awaited tranquility sought by the thousands of people living in the shadow of the University of Colorado A-Line has come with more than a few unwanted bells and whistles.

Since quiet zones were established along the 23-mile corridor connecting Union Station to the airport on March 1, neighbors in Stapleton and Park Hill have been subject to thousands of horn blasts from passing trains. That despite a much-ballyhooed announcement earlier this year by officials from the Regional Transportation District and Denver Mayor Michael Hancock that the cacophony was finally coming to an end.

“They have turned my home into something that is not peaceful — that is not enjoyable to return to,” said Jill Christensen, who has lived in Park Hill Village for nearly three years and whose house is just a few hundred feet away from the A-Line’s Dahlia Street crossing. “At the end of the day, they have me hostage — they have all of us hostage.”

It’s been made worse by the fact that residents were told the horns would largely cease at the beginning of March, only to have them resume at a frequency akin to what railroad regulations mandated before the quiet zones went into effect.

Federal law requires that commuter rail trains sound their horns at at-grade crossings unless those crossings have been granted quiet zone status. RTD’s efforts to silence its A-Line trains were held up for years as the agency struggled to adjust the timing of its safety gates at the 11 crossings along the corridor to regulators’ satisfaction.

“When they said they were stopping the horns, it was like a stress release,” said Robert Leisz, a small business owner whose Stapleton home is less than a mile from the Havana Street crossing.

But within just a day or two of quiet zones being established, Leisz said he heard the horns blaring again as trains rolled over Havana Street. They sounded as early as 4:30 a.m. and late into the night, with few breaks in between, he said.

“Everyone’s just as angry as I am,” Leisz said of his neighbors, who started a robust conversation this week on Nextdoor about the noise and their frustration with RTD.

Pauletta Tonilas, an RTD spokeswoman, said she understands the angst of residents living along the A-Line tracks who have spent the nearly three years since the line first opened in April 2016 putting up with horn noise 21 hours a day.

But the horns went silent again at Dahlia Street on Thursday, after a primary communications trunk, or conduit, that had been mistakenly severed by a contractor laying a giant water pipe for the Platte to Park Hill stormwater drainage project was reconnected.

The conduit controlled the crossing gates and lights at Dahlia Street and with it out of commission, RTD had to put back in place human flaggers and order trains to sound their horns as a safety backstop. Tonilas admitted it was extremely bad timing given the start of quiet zones just days earlier.

“On any given day, anything can happen that we can’t anticipate,” she said. “These things are dynamic.”

RTD acknowledged that there has been frequent horn-blowing at Havana Street over the last month as well. While the agency couldn’t provide a detailed breakdown of the causes of those horn blasts, RTD spokeswoman Laurie Huff said the activations were due to a variety of factors both seen and unseen.

Typically, she said, train operators are directed to blow their horns in a quiet zone if safety is at stake. That can include crossing gate timing issues; workers, pedestrians or vehicles that are on or near the tracks; a sudden emergency; or a train that loses the signal linking it to positive train control, a federally mandated guidance technology that helps prevent derailments and other railroad disasters.

A more accurate moniker for a quiet zone, Huff said, is “an almost quiet zone.”

Christensen said she wished RTD had done a better job of communicating with neighbors about the reason for all the noise near her neighborhood over the past several weeks. The fact that she doesn’t know when the train horns might once again go quiet was the worst part.

“Now that the train horns are back they’ve said nothing to us as to why,” she said.

Meanwhile, the metro area’s transit agency is moving forward with plans to open the long-delayed G-Line, with commuter rail service from downtown Denver to Arvada and Wheat Ridge, on April 26. The 16 crossings on the G-Line will be designated quiet zones on Opening Day.

This story has been updated to reflect the resumption of the quiet zone at Dahlia on Thursday.

A contractor paused its earth-moving work on the west side of the course for more than two months in the late winter and spring, the Denver Department of Public Works has confirmed to The Denver Post. Testing at the time confirmed that the metal was present in unearthed groundwater but at levels considered acceptable in drinking water, DPW spokeswoman Nancy Kuhn said.

But readings exceeded the permitted level for the city to release water into storm sewers in Denver, she said. Manganese but can discolor water and produce a bad odor and taste.

Testing also revealed low levels of uranium in the groundwater, Kuhn confirmed. But the radioactive metal was at concentrations considered safe for drinking, she said, and below the level that would have required filtration under the discharge permits issued for the project by the Colorado Department of Public Health and Environment.

Work on the golf course’s east side was never halted, Kuhn said, and Saunders Construction resumed work on the west side in mid-May.

“The result (of the manganese discovery) is that Saunders is filtering the water prior to discharge, and monitoring is occurring,” Kuhn said.

In a project that drew controversy and a legal challenge, crews are regrading and reconfiguring the historic Denver golf course to accommodate a stormwater detention area as part of the city’s $298 million Platte to Park Hill drainage program. The design and construction contract for City Park Golf Course was valued at $44.9 million.

Word of the contaminants — particularly the uranium — stoked concern in recent weeks among critics of the project. In one email Wednesday to a Denver public health official, activist Bridget Walsh cited suspicions of a “cover-up.”

Kuhn said low levels of uranium are “very common in Colorado and naturally occurring.” The city did not order treatment or filtration of the groundwater before it’s discharged to sewers since it didn’t exceed the limit, she said.

At The Post’s request, Kuhn on Wednesday provided test results for 14 groundwater samples taken between April 6 and July 5. Those figures all were below the drinking water limit for manganese of 190 micrograms per liter, with fluctuating readings topping out at 135 micrograms per liter in mid-April.

The uranium readings all were below of 30 micrograms of uranium per liter for drinking water, ranging from 1.72 to 26.8 micrograms per liter.

“Putting a filtering system in place (for manganese) caused a small delay,” Kuhn wrote in an email last week, “but the project remains on schedule” for completion next year.

Arcis Golf’s renewal notice comes on the heels of its pending lawsuit that aims to force a sale to the Dallas-based operator. The company is the second-largest owner of golf courses in the country.

Last fall, the George W. Clayton Trust, which owns the land in northeast Denver, briefly reached a $20.5 million deal in which the city would buy the course and continue a community discussion over potential future uses. Clayton Early Learning, an early-childhood education nonprofit that manages the trust, has been looking for ways to make more money for its programs than it was reaping from the $700,000-a-year operator lease with Arcis.

But the city’s deal was scuttled in November, when Arcis said it might exercise its option for the first of two five-year lease extensions. Its lease expires at the end of this year, and Arcis had until July 1 to notify Clayton of its decision.

“Arcis has informed us of their intent to renew the lease,” Clayton president and CEO Charlotte Brantley told The Denver Post on Wednesday morning.

Arcis’ lawsuit, filed in April, seeks to activate its contractual right of first refusal to match the city’s earlier purchase offer. But Clayton officials contend that the city’s offer didn’t trigger that provision because the City Council hadn’t yet signed off.

It’s unclear whether Arcis still intends to pursue a purchase of Park Hill. An attempt to reach Scott Siddons, the company’s general counsel, was not immediately successful.

While Arcis may hold legal leverage to continue operating the golf course, company officials also are aware that a city stormwater drainage and detention project — part of — will require the closing of the golf course for up to two years, starting in 2019. Arcis probably will have a claim to compensation from the city during the closure.

Clayton officials are pushing ahead with a planned community open house July 10. They plan to share a summary of the input they have received during a two-year “visioning process” for the property, which has featured passionate arguments for preserving open space as well as addressing needs such as affordable housing.

But that conversation may now be speculative, at best.

“The golf course land continues to be an asset of the Clayton Trust, and its revenue helps support Clayton Early Learning’s mission to improve early care and education during the critical first five years, especially for children living in communities of limited opportunity,” says a statement issued by the nonprofit. “Arcis’ decision does not change our mission, and we will continue our work educating Denver’s children.”

Siddons said during an interview last month that after years of losing money on its lease, Arcis unsuccessfully asked to cut the annual rent back to $400,000.

But he said that last year, for the first time, the operator made a slight profit at Park Hill.

Siddons said the city’s proposal to buy the property last summer took the operator by surprise. The deal could have meant as much as $24 million for Clayton, depending on the site’s development potential.

“We thought that they would be in breach of that lease if they didn’t offer on the same terms to purchase (as the city had offered),” Siddons said. “Our position is: Look, we went through all the bad times on the lease. We upheld our obligations. The fact that you went out and cut a deal with the city — and didn’t offer it to us — is a breach of the lease.”

The company that operates the Park Hill Golf Course filed a lawsuit this week against the private trust that owns it, throwing another wrench into discussions about the future of the 155-acre property in northeast Denver.

Dallas-based operator Arcis Golf contends that a scuttled plan by the city of Denver to buy the land should have triggered Arcis’ contractual right of first refusal to purchase the course itself, according to its lawsuit, filed in Denver District Court. It targets Clayton Early Learning, an education nonprofit that manages the George W. Clayton Trust, which owns the land.

The city suspended its plan in November after Arcis notified Clayton that it was still considering whether to renew its lease, which expires at the end of 2018. Arcis has until July to do so, but Clayton has portrayed it as a money-losing venture for the operator.

Arcis’ lawsuit, filed Tuesday, suggests the company wants to purchase the land, and on the same terms that the city proposed.

In September, Clayton and Denver city officials  that could have brought upward of $24 million to Clayton, depending on the site’s development potential. The proposal came amid a still-unresolved public conversation that has explored both the land’s open-space potential and its development prospects, with vocal advocates on each side.

“We do not understand the motives of Arcis Golf in filing the suit,” Charlotte Brantley, Clayton Early Learning’s president and CEO, wrote in an email Friday to members of a community advisory committee. “If they were interested in continuing to operate the golf course they could simply choose to renew the lease.”

Attempts to reach Arcis’ local attorney, Frank W. Visciano, were not immediately successful.

Arcis’ lawsuit accuses Clayton of breaching its lease after it asked to match the city’s offer last fall, and it seeks a court order allowing it to do so. It says that Arcis asked Clayton on Nov. 28 for a written notice outlining the city’s offer and to give Arcis 30 days to agree to those terms.

But Brantley said Friday that the organization disagrees with Arcis’ contention that the city’s proposal triggered the operator’s contractual right of refusal.

“We have long acknowledged that Arcis Golf has a right of refusal to purchase Park Hill Golf Course, which we intend to honor, but that right is dependent on Clayton receiving a binding written offer from a third party,” Brantley wrote in the email. She added that the city’s proposal “was never approved by City Council nor signed in any form by the city, and thus did not meet the requirements in the lease of a binding offer.”

Denver Public Works received council approval in January to negotiate easements on the golf course for a stormwater detention project.

Here is Arcis’ lawsuit, filed in Denver District Court:

But the ruling, issued late in the day Friday in U.S. District Court in Denver, allows the Sierra Club and several neighborhood and community groups to seek more information from federal officials about why they made disputed changes to air-quality modeling.

The order comes after the presiding judge in the case, William Martinez, ruled last week that the project could begin construction on the 10-mile widening project this summer while the plaintiffs continue their court challenge.

In the new ruling, Magistrate Judge Michael E. Hegarty denied the Sierra Club’s motion to supplement the administrative record underlying the approval of the project by the Federal Highway Administration (FHWA) in January 2017. The decision ended an extensive environmental impact review on the Colorado Department of Transportation’s $1.2 billion project, which includes replacing the nearly 2-mile viaduct through the Elyria-Swansea neighborhood with a wider highway that is sunken below ground level into an open trench.

“I first find plaintiffs have not met their burden of establishing any of the narrow exceptions that would entitle them to supplement the record,” Hegarty wrote in the 25-page order. “Importantly, none of the documents plaintiffs submit demonstrate that FHWA failed to consider a relevant factor,” the project’s impact on human health.

The magistrate judge also partially denied another motion’s attempt to allow other outside material, while allowing for “limited discovery” on the air-quality modeling.

On that issue, the FHWA has defended its decision to change the projection modeling for particulate concentrations at seven data sites, out of more than 3,200, so that they were based on the actual elevated height of the rebuilt freeway near the Interstate 25 interchange. The rest of the sites were calculated at ground level.

The Sierra Club’s outside expert found the modeling change averted the violation of federal standards for five of the seven sites, but FHWA denies that was the motivation. Hegarty ruled that the Sierra Club may submit five written questions in coming weeks “related only to FHWA’s decision to separately model the seven receptor locations.”

The Sierra Club, joined by neighborhood and community groups, was in court last week presenting new analytical work by outside experts to buttress its case. But while the court has not ruled on two motions related to that evidence, Tuesday’s separate order rejects a larger motion to halt the project — and asserts that the environmental group has not demonstrated it is likely to succeed in its challenge.

U.S. District Court Judge William Martinez found that a 14-year environmental impact review by the Federal Highway Administration and the Colorado Department of Transportation relied on the correct federal air-quality standards. Those were used to find that the expanded freeway, as proposed, would not exceed safe emission levels in coming decades.

The Sierra Club has argued that those standards were insufficient to protect neighbors’ health in Elyria-Swansea and Globeville, raising the risk for asthma and cardiovascular disease.

But Martinez wrote in his 22-page order that the opponents failed to propose a consistent standard that could be used to determine when more health-impact investigation is warranted for a project when it already meets established federal standards.

Although the Sierra Club’s case still can proceed to full arguments, the ruling has removed the last potential legal roadblock for construction to begin on the I-70 project.

“The court����ap decision, along with , confirms CDOT’s long-standing position that the diligence and community-centered focus that led to the Central 70 Project would stand up to the toughest legal scrutiny,” deputy project director Rebecca White said in a statement Tuesday. “While this is not the final step in the legal process, it is an important validation of the work we have done and will continue to do as we move this important project forward.”

The ruling was on a motion for a stay on the I-70 project, which is what courts call a preliminary injunction request in an agency-review action. The Sierra Club’s lawsuit, filed last summer, challenged the FHWA’s approval of the project in early 2017.

Attorney Bob Yuhnke said the group likely would ask Martinez to reconsider, based on arguments that he said weren’t addressed in the ruling. And he said the pending rulings on the outside experts’ analysis could be crucial, as well.

“Clearly, we are disappointed by Judge Martinez’s decision not to order a delay in federal funding of the I-70 project until its negative health impacts on north Denver residents can be more fully assessed,” Lloyd Burton, chairman of the Colorado Sierra Club’s Environmental Justice Team, said in a statement. “North Denver neighborhoods along the I-70 corridor already suffer far higher rates of childhood asthma attacks and congestive heart disease than anywhere else in the city, and allowing the project to go forward will only make the ongoing threats to their health that much worse.”

Burton said the Sierra Club’s attorneys would consult with the group’s co-plaintiffs, the Elyria-Swansea Neighborhood Association, the Chaffee Park Neighborhood Association and Colorado Latino Forum.

All of the groups have vowed to fight the project to the end.

Set to break ground this summer, the 10-mile widening project will add a tolled express lane in each direction, with room for a second toll lane in the future. The highway currently has three through lanes in each direction.

The most complicated section involves the replacement of an aging 2-mile viaduct between Brighton and Colorado boulevards with a section of highway that’s sunken below ground level into an open trench. A portion next to Swansea Elementary will be capped by 4 acres of parkland.

As part of his ruling, Martinez found that cited by opponents — linking poor air quality to asthma and other health problems in the project area — was insufficient to require the FHWA and CDOT to study the project’s impact further.

The ruling says the city study “is not an empirically rigorous document, as it generally reports only on correlations, without any inquiry into causation, contrary to the scientific method. And, importantly, it utterly fails to control for, among other things, the contribution made to the prevailing health of the communities adjacent to I-70 by adverse socioeconomic factors apart from proximity to the freeway.”

Last year, CDOT selected  for a complex public-private partnership contract in which it will finance, design and build the Central 70 project in the next four years, and then operate and maintain the widened highway for three decades. The contract sets out an estimated $2.2 billion in costs for CDOT over the course of more than 30 years.

Here is Tuesday’s ruling denying a motion to stay:

They don’t think that’s a coincidence, given the soot and other pollutants that waft off the freeway. And Denver at least confirm that children in Sanchez’s Elyria-Swansea neighborhood, which also has several industrial operations, seek asthma-related treatment in emergency rooms at a rate that’s 40 percent higher than the city as a whole.

“Living next to the highway has not helped me to improve in the slightest,” Sanchez said. He has watched his mother, Yadira, develop an even more severe case of asthma that limits her ability to work.

In a legal challenge of the Central 70 project, attorneys representing the Sierra Club and community groups argued in court this week that the expansion of the highway to handle more traffic will only exacerbate already-prevalent health risks for nearby residents. They also face higher chances of developing deadly cardiovascular disease.

And the Sierra Club cited new analytical work done by two outside hired experts to buttress its argument that the Colorado Department of Transportation and federal officials, during the decade-long environmental impact study for the project, neglected to fully consider the highway expansion’s health ramifications. The group is asking for that new research to be admitted as evidence in the court record, with a ruling expected next week.

The plaintiffs also argue that the federal standards officials used were woefully inadequate to safeguard public health.

In one instance, officials decided to change the air-quality modeling procedure used for a handful of data sites, basing the calculations on the elevated height of the highway near the Interstate 25 interchange instead of at ground level, as was done elsewhere. The Federal Highway Administration (FHWA) still contends that decision was appropriate.

But the Sierra Club’s expert showed that the altered calculations averted particulate-emission projections at five sites that would violate federal standards decades into the future.

“In this case, all of the issues that we’re raising are related to health,” attorney Bob Yuhnke said during Wednesday’s hearing in U.S. District Court in Denver. “The consequences that this project will have with regard to health have not been explored.”

On Thursday morning, Yuhnke joined more than two dozen I-70 project opponents on Columbine Street, near the viaduct, to press their case to the public. If the activists are successful in court, CDOT and the FHWA could be forced to delay part or all of the 10-mile widening project while they restudy the community health effects, potentially resulting in project changes or further mitigation measures.

The project includes the addition of new tolled express lanes. Between Brighton and Colorado boulevards, the 2-mile viaduct will be replaced with a wider highway that is sunken below ground level into an open trench — hence the “Ditch the Ditch” rallying cry of opponents, many of whom want CDOT to re-route I-70 to the north.

CDOT plans a host of mitigation efforts aimed at shielding neighbors from noise and dust during the nearly four years of the project. Its largest concession will be a 4-acre parkland cap over the sunken highway next to Swansea Elementary.

“Nearly every aspect of CDOT’s 14-year effort to address the I-70 east corridor has been focused on the Elyria-Swansea neighborhoods,” said Rebecca White, a deputy project director, in a statement. “This process led us to a solution that meets the Clean Air Act’s stringent health requirements; delivers millions of dollars in unprecedented improvements to housing, food access and schools within Elyria-Swansea; and delivers a safer, more mobile highway for all of Colorado.”

So far, other attempts to challenge the project in court have faltered.

And in this case, the Sierra Club’s request to add the new outside evidence to the court record for consideration by Judge William Martinez faces potentially significant legal hurdles.

Because the lawsuit challenges the project’s federal approval, received in January 2017, normal court procedures limit the scope for a judicial review only to the research and analysis actually considered by officials before they made the decision, called the “agency record.”

That was the argument pressed by CDOT and FHWA attorneys Wednesday. They also defended the health and air-quality factors that were considered in the federal project review as meeting all requirements.

“At some point, you’ve got to call it good, and the process needs to come to an end,” said Nicholas DiMascio, an attorney for CDOT.

The Sierra Club raised similar concerns during the environmental-review process in its formal comments. But Yuhnke said state and federal officials didn’t fully address such concerns. The new health and air-quality modeling research, done by professors at the New York University School of Medicine and the University of New Mexico’s School of Engineering, only underlines the group’s earlier-stated doubts about the project, he said.

That argument gave pause to Magistrate Judge Michael E. Hegarty, who works under Martinez.

“The major point that maybe has some traction is this: There is data that could be generated that wasn’t — so obviously, (the Sierra Club) couldn’t put that in front of the government unless they had spent a lot of money conducting an analysis that they claimed the government should have,” Hegarty told the lawyers.

Under consideration are a discovery motion and a motion to supplement the administrative record with the experts’ research, both filed by the Sierra Club.

A ruling by Hegarty next week would clear the table for Martinez to consider the Sierra Club’s motion to halt the I-70 project while the court review continues. Both sides are expected to file written briefs in coming months, before a full court hearing on the Sierra Club’s challenge.