C.J. Schexnayder/ENR Karen Klotz, Michael Sanio, ASCE director of International Alliances and ASCE President-Elect Wayne Klotz peer through a reconstructed doorway in the Incan citadel of Machu Picchu in Southern Peru.

CUSCO, Peru - Kenneth Wright has devoted a hefty portion of the last three decades to the study of the Incan city of Machu Picchu in Southern Peru. Finally, he’s succeeded in leaving his mark on the famed lost city.

Wright, president of Denver-based Wright Water Engineers, championed the naming of Machu Picchu and to ASCE’s Historic Civil Engineering Landmark Program. Last month, a delegation of ASCE members including President-elect Wayne Klotz traveled to Peru to take part in ceremonies dedicating the plaque that will be placed at the entrance to the site.

The group also took part in a multi-day seminar at the University San Antonio Abad de Cusco (UNSAAC) examining the importance of the sites and the most recent findings concerning them both.

Both Machu Picchu and another important Inca site in the Cusco region, Tipon, were formally granted landmark status in 2006 in a ceremony in Atlanta, Ga. Since 1966 the Historic Landmark program has recognized more than 200 sites deemed structurally or technically unique and of historic civil engineering significance.

“ASCE is committed to recognizing the engineering achievements that serve as the origin of modern civil engineering,” Klotz said. “By highlighting sites such as Machu Picchu and Tipon here in Peru, we can promote history as a guide to contemporary, sustainable engineering practice.”

C.J. Schexnayder/ENR Ken Wright, president of Denver-based Wright Water Engineers, helps place a plaque at the entrance of Machu Picchu indicating the site’s designation as part of the ASCE’s Historic Civil Engineering Landmark Program.

Peruvian officials say the award is important because it encourages greater technical study at the sites as well as other important locations across the country.

Machu Picchu is one of the most famous archeological sites in the world. Last year more than 750,000 people visited the site, a number expected to increase by at least 10 percent this year, according to the Peruvian Ministry of Foreign Trade and Tourism (Mincetur).

The remains of the citadel cover about 25 acres atop a ridge more than 1,500 feet above a bend in the Urubamba River in Southern Peru. The site is part of the high jungle and the location receives almost 80 inches of rain annually.

Between those two factors, the fact Machu Picchu did not “slide off the side of the mountain” is proof of the expertise of the engineers that constructed it, Ken Wright said.

Wright and his wife Ruth have authored books on Machu Picchu and Tipon in association with Peruvian experts whose English-language editions are published through the ASCE press. They are currently working on a new book that will examine another Incan archeological site in the Cusco region, Tipon.

In addition, Ruth Wright’s guidebook for Machu Picchu that is considered one of the most authoritative available and that has sold more than 80,000 copies.

Machu Picchu was built in the middle of the 15th century under the orders of the supreme ruler of the Inca Empire, Pachacuti. After the Spanish conquest a century later, the site was abandoned and almost completely forgotten.

C.J. Schexnayder/ENR Kenneth and Ruth Wright examine some of the waterworks at the Incan site Tipon which has been included in the ASCE’s Historic Civil Engineering Landmark Program.

It was not until 1911 when Yale University Professor Hiram Bingham re-discovered the ruins that the outside world became aware of its existence.

The actual purpose of the site and the specific methods of construction remain a topic of heated debate among archeologists and anthropologists. Engineers, on the other hand, have the luxury of studying the well-preserved remains of the citadel, Ken Wright said.

“The evidence is all right there,” he explained. “To study it is to be able to study what the Inca engineers were doing and thinking.”

As much as 60 percent of the building effort went to site preparation, drainage and foundations, he says. Almost half the work that went into the site lies below the surface itself. The most visible aspect of that effort is the more than 700 terraced walls around the site that ensure slope stability.

While not as architecturally striking, Tipon is nothing less than a masterpiece of hydraulic engineering. Located about 13 miles south of Cusco, the site boasts some of the most advanced hydraulic and geotechnical engineering in the pre-Spanish Americas.

“At Machu Picchu, the hydraulic engineering was aimed to provide water for the populace while at Tipon it was also for irrigating the agricultural zones of the settlement,” Ken Wright said.

To do that, the engineers integrated water from a spring in the hills as well as waters from the river below all of which still function much as when they originally were constructed.

The achievements of these ancient engineers resound today because they had mastered the techniques of their craft needed to handle the environment they were working in – the same task engineers working on projects today must face.

“The natural phenomena that have to be coped with haven’t changed,” Ruth Wright said. “Water still flows downhill.”