The Colorado Department of Transportation project on Vail Pass seems simple enough: enhance and repair seven retaining walls on the west side of the pass.
The task took about a week as crews focused on slowing the deterioration of walls built in 1975, part of a game-changing decade that carved I-70 through the mountains west of Denver, including routing the highest point of the nation’s interstate system under the Continental Divide at the Eisenhower Tunnel.
“So they can last another few decades,” said Peter Lombardi, CDOT’s resident engineer who helped manage the $2.1 million project, which also included maintenance on one retaining wall at Dowd Junction west of Vail.
Lots of criteria go into CDOT mountain projects like this. First and foremost, of course, is safety and efficiency. There’s also structural integrity, safeguarding against high country snow and melt cycles, protecting water and wildlife, and minimizing disturbance to traffic flows and the environment.
But the Vail Pass project had an extra goal: preserve the historical integrity of several of those retaining walls. That’s right, there’s important architectural history in the humble concrete barriers holding the mountain back from the pavement.
The rough-textured, reddish-pink panels, curved and angled to follow the sloping mountain and winding roadway, were designed, in part, by landscape architects from Taliesin Associated Architects of the Frank Lloyd Wright Foundation.
Those adherents of Wright, who were part of the 1972 team that designed the 15.2-mile corridor, sketched the retaining walls — and also influenced slope treatments, bridges and culverts — in keeping with the famed architect’s doctrine of “organic architecture” that holds that man-made structures “can be harmonious enhancements of nature.”
Wright designed some 1,100 structures over a 70-year career, about half of which were built. His followers designed and built thousands more. Wright and his Taliesin students are well known for their unorthodox buildings — trophy homes, offices, resorts, theaters, churches, museums — but not necessarily recognized for such a project so pedestrian as highway retaining walls.
In general, landscape architects were not deployed in the early design of highways or roads in the 1970s. Usually they were called after the fact to cover construction scars. And while CDOT’s Vail Pass, Eisenhower and Johnson Tunnels and Glenwood Canyon are revered as engineering marvels in the country’s interstate highway system, both Vail Pass and Glenwood Canyon pioneered innovations in the realm of landscape architecture.
The earthwork above the Vail Pass interstate, with sculpted rocks cut to match outcroppings and selective scatterings of boulders, stumps and downed timber, was part of the design plan from the start. One-of-a-kind retaining walls, terraced with curves, angles and pockets for patches of native grass, held back slopes. Sculptured bridges followed the curve of the mountainside. Concrete was not smooth or flat, and it was mixed with iron oxide for a muddy red hue to match cliffs above the highway.
“Unique and innovative landscape elements were integrated into the highway design to enhance the experience of motorists on the interstate segment,” reads a report prepared by architectural consulting firm Mead & Hunt this summer for CDOT outlining the historical context of the Vail Pass segment of I-70.
CDOT tries to incorporate Wright’s blending-with-nature approach at Vail Pass into all its projects now, said Lisa Schoch, the agency’s staff historian.
“Especially in the mountain corridors, where there is a lot of sensitivity toward context with the surrounding environment,” Schoch said. “Vail Pass and Glenwood and the tunnel system are arguably some of our greatest achievements in the highway department.”
In the 1950s and 1960s, before an environmental movement birthed the creation of the National Environmental Policy Act and a flurry of trailblazing laws protecting wilderness, water, and wildlife, highways were no-frills affairs: straight, level and cheap. The decades-in-the-making plan for Colorado’s I-70 mountain corridor helped change that approach, with environmental campaigns persuading road builders to veer around a 133,000-acre swath of roadless wild lands that eventually became the Eagles Nest Wilderness in the Gore Range.
So I-70 over Vail Pass roughly followed the uninspired U.S. Highway 6 over the 10,666-foot pass. But from the outset, the design team aimed to “rectify the past errors” of the old route, according to a booklet, penned by CDOT, Forest Service and Federal Highway Administration, that outlined the project. The project also set “standards of excellence” for other highways, applying Wright’s theory that man-made structures — even highways — can be harmonious with nature.
The 21.4-mile stretch of I-70 between Vail and Frisco opened in 1978, the first built by the Colorado highway department after review under NEPA. It cost $91 million, including $775,000 for the adjacent bike path. (Although the 12-mile highway through Glenwood Canyon was evaluated under NEPA in the early 1970s, construction did not begin until 1980.)
“You have this sense of environment and not just because of environmental laws,” Schoch said. “Of course Vail Pass was built following NEPA and environmental laws, but we rose to the occasion at Vail Pass, just as we did in Glenwood Canyon and really ever since. We often think, let’s try to have that same vision with all our work. What a great standard we set for ourselves in Vail and Glenwood.”