Returning Guanella Pass To Nature

By Carol Carder | September 28, 2010

"Nobody had ever done an alpine tundra project of this scale," says Ron Dean of American Civil Constructors Inc. (ACC), Centennial, Colo., speaking of the successful high altitude sod transplant on Guanella Pass above Georgetown, Colo. "We literally had to invent the tools in shop and partially in the field to do the job."

A year after placement, transplanted willows in a former parking area are growing well and appear completely natural. Photos courtesy FHWA.

The Associated Landscape Contractors of Colorado recently recognized this reclamation project in its Excellence in Landscape awards. The $180,000-reclamation including the alpine tundra transplant is part of the $20-million Phase I improvements of nearly nine miles of the Guanella Pass road between 2004 and 2007. Rocky Mountain Construction reported on the roadwork and retaining walls in its Nov. 13, 2006, issue.

Along the pass, hikers and day users had pulled cars off the side of the road, forming parking spaces that grew larger over the years. With frequent rain a nd snow at this altitude, soil from these ad hoc parking spaces was eroding, sending mud and sediment into the streams feeding into pristine mountain lakes. The Federal Highway Administration's Central Federal Lands division decided to build a couple of large asphalt lots up top with proper drainage and close off the along-the-road parking spots. In July 2004 the construction arm of ACC did the preparatory work for the drainage on the lots, then the landscape

Harvesting natural sod – on a rainy day – using the specially made bucket on American Civil Constructors’ Bobcat T300 track skid-steer loader.

division began cutting 4,400 square meters of alpine tundra sod from these lots and transplanting it along with rocks to discourage more parking in the former spaces along the road.

"Because the optimum growing season is about a month long at 11,000 feet, the timing for the transplant operation was critical so the sod could establish root systems before winter," Dean explains. "The next year after the spring thaw, the sod came back so well you cannot tell it was ever moved."

To harvest the sod ACC built a specialized bucket with a cutting edge for its Bobcat T300 skid-steer loader. To transport the sod to the old parking spots, workers built a flat metal plate approximately 4 feet square for another skid-steer loader. One of the necessary field adjustments employed duct tape and bailing wire to attach a mirror to the harvesting skid-steer bucket so the operator could tell when the sod reached the back of the bucket. The harvesting skid steer then transferred the sod to the flat plate on the second skid steer to trundle it down the road. There laborers hand-filled the seams between the sod pieces with topsoil and tamped it down.

The original plan was to transport the sod on the longer hauls of up to a mile and a half by trailer. The trailer bounced so much on the rough road, the sod disintegrated. According to Dean, the crew came up with the idea of using balloon-tired all-terrain vehicles to transport the sod. So ACC rented a couple of Bobcat diesel-powered all-terrain dump vehicles and a John Deere Gator to move the sod.

In widening the road in some places as much as 10 feet to 15 feet, ACC tore out the existing vegetation. So after the roadwork, the landscape division went through and recreated the ditch line, seeded native grass and native plants, and planted willow stakes cut off on-site willows. The workers also collected native raspberry seed on site and sent the seed to a nursery to grow for transplanting the next season. The reclamation work required 2,400 square meters of erosion blanket; 80 acres of hydraulic seeding, mulching and amendments; 21,000 willow transplants; and 3,651 container plants.

"In some places it was too rocky for vegetation, but any place where there was any chance of getting something to grow we seeded it or planted it," Dean says.

"Overall, we take pride in knowing we played an important role in a project as big as this was," Dean concludes.

Westerly Creek

When Denver's Stapleton International Airport closed in 1995 after the opening of the new Denver International Airport, the former airport property was opened to massive redevelopment and has since become an urban redevelopment success story of national import. The redefining of Stapleton's Westerly Creek South area started with a vision developed by a 42-member Citizen's Advisory Board. The Stapleton Development Plan, also known as "The Green Book," envisioned balance in a network of urban villages, employment centers and significant open spaces. The 4,700-ace community began in 2001 is the largest urban infill project in the nation. Now 25 percent complete, full build-out is expected by 2020.

"We transformed a utilitarian concrete culvert that once drained water from the runways and taxiways into a stream with curves, bike and walking trails, and wildlife habitat," says Blake Williams of CoCal Landscape, Denver.

Westerly Creek South still filters surface drainage, providing stormwater management, but now the water moves through wetlands and along paths with abundant wildlife. The foliage along the creek provides habitat for eagles, fox, deer, coyotes, and blue heron.

The site now has a reclaimed water management system. Recycled concrete from the former runways underlies paths, supports park benches and controls erosion in the drainage channel.

A major challenge for landscape architect EDAW and contractor CoCal Landscape was the poor soil conditions. Glycol from the deicing of planes is suspected as a contributor to the excessively high salt content in the soil. To remedy this condition, the contractor substantially over-excavated the tree pits and added a special mixture of topsoil, expanded shale and soil amendments to ensure healthy plant growth.

CoCal planted approximately 500 evergreens and deciduous trees with balled and burlapped roots, 2,600 shrubs and 4,000 perennials. Also, the project area was seeded with a native seed mix and drought-tolerant plants installed.

The Associated Landscape Contractors of Colorado recently recognized this reclamation project in its Excellence in Landscape awards.