Engineering in the Wild
BY MATTHEW McLAUGHLIN
On August 25, 1916, President Woodrow Wilson signed the “Organic Act” that established the National Park Service, the fundamental purpose of which was “to conserve the scenery and the natural and historic objects and the wildlife therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations.”
Just having celebrated its 100th birthday, the National Park Service has grown to manage 410 parks that make up the National Park System, which covers more than 84 million acres and includes 128 historical parks, 81 national monuments, 59 national parks, 25 battlefields or military parks, 19 preserves, 18 recreation areas, 10 seashores, four parkways, four lakeshores, and two reserves.
Together the National Park Service’s 410 parks contain 247 species of threatened or endangered plants and animals, 75,000 archeological sites, 27,000 historic or prehistoric structures, and 18,000 miles of trails. And in 2015, those parks together had 307.2 million visitors.
The National Park System is beloved by many Americans. A 2012 poll commissioned by the National Parks Conservation Association and the National Park Hospitality Association found 95% of voters see “protecting and supporting the national parks” as an appropriate role for the federal government, and 77% of voters believe it is important for the next president to ensure that parks are fully restored and ready to serve and be relevant to this country for another hundred years.
All of this though—the size of the national park system, its popularity, and its successful preservation both of natural and cultural resources—surprisingly, has hinged in part on the work of devoted engineers. The significance of engineers is fairly apparent looking at monuments on the National Mall or out toward the Golden Gate Bridge from the Golden Gate National Recreation Area, but what can go unnoticed is how engineers have shaped the entire National Park System and the experience of visitors.
“National parks have never been just about preservation,” says Tim Davis, historian with the National Park Service Historic Structures and Cultural Landscapes Program. “They’ve been about balancing preservation and access.” And engineers, he adds, have played a major role in the planning and design of roads and other infrastructure to provide access in balance with preservation.
Engineers haven’t just been a part of the ongoing conversation that takes place today, but it was actually engineers who really established the philosophy of balancing preservation with access before the National Park Service even existed. When Yellowstone National Park (the nation’s first national park) was established by Congress in 1872, responsibility for roads, bridges, and trails was given to the US Army Corps of Engineers, and from the start, they endeavored to build no more roads than necessary and roads that didn’t “impinge” on the scenery, according to Davis.
The “premier engineer” of Yellowstone was Hiram Chittenden, who also wrote books about the park and articulated policy on park service growth and development, says Davis.
One of his favorite Chittenden quotations: “The true policy of the government in dealing with this problem should therefore be to make the roads as limited in extent as will meet actual necessities, but to make those found necessary perfect examples of their class.”
The characteristics of a perfect park road have been discussed and debated ever since, with the input of engineers, landscape architects, environmentalists, and other experts and stakeholders, but Chittenden and other Army Corps engineers started those conversations. Because of them and the many others who followed, the National Park System became what it is today in terms of preservation, access, and visitor experience.
Roads, says Davis, are a very important part of the effort to balance preservation and access. “The park road experience is the national park experience for many people, and it’s very carefully conceived to lead you on this choreographed route through natural or cultural landscapes and to minimize its own impacts on them.”
A PANORAMIC VIEW FROM GLACIER NATIONAL PARK’S GOING-TO-THE-SUN ROAD.
CREDIT: NATIONAL PARK SERVICE
While their impact has been significant, roads and other infrastructure aren’t the only contribution engineers have made to the National Park Service and the National Park System. They also play an active role in preservation.
Engineers based at the Denver Service Center in Colorado come from numerous disciplines and work on projects of all kinds. The Denver Service Center is the central planning, design, and construction management project office for the National Park Service.
A lot of work involves updating or rehabilitating infrastructure important to park access, according to NSPE member David Engelstad, P.E., but the center also handles preservation and historic rehabilitation projects. Engelstad, an engineer with the US Public Health Service, was design branch chief at Yosemite National Park for eight years and recently became a project manager for the Denver Service Center’s Design and Construction Branch. His current projects include the restoration of an aqueduct at the Chesapeake & Ohio Canal National Historical Park and the replacement of electrical lines that were built in the 1930s on Staten Island in New York.
The center’s projects, Engelstad says, “can be almost anything that you see out in the park.”
Regardless of whether a project is related to accessibility and infrastructure or preservation, two issues have put increased pressure on engineers: climate change and uncertainty about funding. The challenge for engineers working with or for the National Park Service for the next 100 years, according to Engelstad, is not only continuing to balance access with preservation, but also balancing funding with robust designs that will last.
“We don’t see a lot of public dollars come along,” Engelstad says, which makes it all the more important to get each project right. “We may not have that opportunity again for another 50 years.”
Glacier National Park’s Going-to-the-Sun Road
Spanning the width of Glacier National Park, the Going-to-the-Sun Road is one of the park’s most popular destinations. The 50-mile, two-lane road provides access to the heart of the park and the Continental Divide, while treating visitors to views of glacier-carved peaks, alpine lakes, and lush forests. Its completion in 1933 was the result of more than a decade of planning and construction.
VISITORS TO GLACIER NATIONAL PARK’S GOING-TO-THE-SUN ROAD DON’T HAVE TO GET OUT OF THEIR VEHICLES TO ENJOY SPECTACULAR VIEWS. CREDIT: NATIONAL PARK SERVICE
Aside from its “spectacularity,” the Going-to-the-Sun Road is very important in terms of its aesthetics as well as the ideology and bureaucratic relationships of park road building, Davis says. At the time of the road’s construction, engineers from the Army Corps were no longer in the picture, and the National Park Service had its own engineer.
George Goodwin, the very first National Park Service engineer, in 1918 planned the route that became the guideline for the road. His original route is very similar to that of the actual road with the notable exception of a steep climb he planned to the Continental Divide using 15 switchbacks.
Goodwin, whom Davis describes as dynamic but arrogant and irascible, challenged the philosophy of balancing access with preservation, believing engineering was on par with nature and that roads could add beauty to landscapes. “And that’s not what the park service wanted,” Davis says.
Goodwin pushed for his vision, but ultimately the National Park Service turned to its landscape architects and engineers from the Bureau of Public Roads to complete a final design more in line with the philosophy followed by Army Corps engineers. That design is “generally regarded as a resounding success” because it is much less intrusive and gives visitors spectacular views, Davis says.
The successful project resulted in a memorandum of agreement between the National Park Service and BPR that exists in modified form to this day, outlining how the two agencies will collaborate to design park roads.
Blue Ridge Parkway’s Linn Cove Viaduct
Stretching for 469 miles along the crest of the Blue Ridge Mountains through Virginia and North Carolina, the Blue Ridge Parkway is the longest road planned as a single unit in the US, taking visitors through a series of parks and over high mountain passes with panoramic views. It was originally conceived during the Great Depression as part of President Franklin Roosevelt’s New Deal, but it wasn’t completed until 1987.
The project was obviously a great undertaking, requiring a huge investment of time and resources, but a controversial segment of the route around Grandfather Mountain in North Carolina added years to the project. The rest of the parkway was open to the public roughly 20 years prior.
Environmental concerns drove the controversy, specifically concerns about building a road across a steep, ecologically and environmentally sensitive terrain, Davis says.
The National Park Service, landscape architects, and Federal Highway Administration engineers agreed the road should be elevated where possible to eliminate massive cuts and fills. However, doing so along the face of the mountain at an elevation of 4,100 feet was an enormous challenge for engineers.
In 1973, the project team decided on a complex viaduct that wraps around the mountain for about a quarter of a mile and is built on a very small number of pylons, says Davis.
Figg and Muller Engineers designed the viaduct and developed the construction method, which used progressive placement to build the viaduct from the top down. This eliminated the need for a “pioneer road” and heavy equipment on the ground. The only construction that occurred at ground level was the drilling of foundations for the seven permanent pylons that support the viaduct.
“The Linn Cove viaduct was the first application of this extensive progressive placement in the US,” Davis says. Engineers and builders measured, designed, and then cast offsite 153 separate and different segments. They would trundle one out onto the growing viaduct, hang it off the end, stick it together, and then build the next one.
“It’s a beautiful structure,” Davis says. “It’s become an icon of the Blue Ridge Parkway.”
Chesapeake & Ohio Canal National Historical Park’s Conococheague Aqueduct
Earlier this year, the National Park Service announced a $1.3 million project to rehabilitate the Conococheague Aqueduct, part of the Chesapeake & Ohio Canal in Williamsport, Maryland.
An engineering achievement in itself, the C&O Canal operated for almost 100 years along the Potomac River between Washington, D.C., and Cumberland, Maryland, transporting coal, lumber, and agricultural products. Today the canal serves as an expansive park filled with both natural and cultural resources. The towpath running alongside the canal has been maintained along the entire length for recreational use, but the canal and its locks have been rehabilitated or maintained for historical interpretation in only a few areas.
“The park would like to start watering a lot of these channels and locks just so visitors can get a real feel of how they operated historically,” Engelstad says. To do this, engineers have to consider the environment and work closely with historians to ensure the projects are true to their originals.
Protecting the environment and maintaining the historical integrity of the structure have been particularly challenging in the case of the Conococheague Aqueduct. The original structure was made entirely of stone, but when one of the walls collapsed in the early 20th century, it was rebuilt using timber, which is now gone as well. Recovering the original stone from the creek poses environmental challenges, while the case can be made not to use stone, old or new, at all.
Engineers also have to look at the integrity of the historic designs before using them again, according to Engelstad. And if they are structurally unsound, engineers have to figure out how to make them safe while maintaining their historic nature.
Despite the challenges, the 196-foot Conococheague Aqueduct is well on its way to educating and entertaining visitors. Engineers have almost wrapped up the design and preliminary work began at the site in May.