An arch dam doesn’t rely solely on thick concrete to hold back the water. Instead, it curves elegantly with its convex face directing the water to the walls of the canyon it spans. It can be much thinner than a corresponding gravity dam and, therefore, it requires fewer materials and can cost less, according to dam experts. 

That means lower-cost power and more reliable water supplies, often in places where both would otherwise be scarce. That fact shaped Wengler’s passion for the work, his former colleagues say.   

Wengler joined the U.S. Army in November 1945, shortly after the end of World War II. He was assigned to the Signal Corps in Germany. Following his discharge, he went to the University of Minnesota on the G.I. Bill, graduating with bachelor’s degrees in civil engineering and business administration and a master’s in civil engineering. 

Early Adopter of Computers

At a time when most engineers were still relying on slide rules, Wengler adopted computers, which he had learned to use in accounting classes. That gave him the ability to quickly do the kinds of mathematical calculations that a thin-arch dam required. While his colleagues appreciated his engineering savvy and admired the speed of his calculations, for a long time, they remained skeptical about the value a computer could bring to the miracle of design that was thin-arch construction, according to colleagues.

Wengler liked to tell this story about his early days at Harza when he helped the company win a big contract because it could build a dam much cheaper than competitors who relied on older designs. After they were leaving the bid interview, firm owner Dick Harza slapped Wengler on the back and said, ‘Well done, Roman. Now let’s hope it doesn’t fall down.’”

One of Wengler’s favorite projects was the Mossyrock Dam in Washington State, completed in 1968. It remains the state’s tallest dam and produces enough electricity to light 87,000 houses annually.

“I met Roman for first time at the Mossyrock site,” says Stephen O. Simmons of the Kiawah Consulting Group. The environmental scientist worked for Harza as a consultant. 

“It was a unique design for the time and Roman was a giant in the industry,” adds Simmons. “I remember him as hugely competent.”

Wengler was recognized for his work as lead design engineer for the Mangla Dam on the Jhelum River in Pakistan. Its completion in 1967 ensured that the country’s irrigation systems would work as intended. Mangla remains the sixth-largest dam in the world.

Wengler also worked on dam projects in China, Iran, Tanzania, Uganda, Venezuela, and Zimbabwe. He was part of a team of international consulting engineers working on the Ertan Dam on the Yalong River in the Sichuan province of China.

China opened the massive Ertan project to international competitive bidding because at the time, it didn’t have the expertise required. Construction began in 1987. 

Wengler was among those honored by the Chinese for his work on the dam project. At a celebratory banquet, Wengler noticed that Communist Party chair Deng Xiaoping, a leader who pushed for economic reform, was standing alone and apart from the crowd. He walked over and introduced himself, initiating what became a lengthy conversation, according to others who heard Wengler describe the encounter.

Wengler was known for his people skills, says Richard Esser, a former Harza engineer. 

“He would come out of his office and stand up against a tall filing cabinet,” recalls Esser, who had an office near Wengler’s. “He'd be in a conversation with somebody and before you knew it, three or four of us would be there listening to him,” says Esser. “He always had a big smile and you could hear him laugh.”