Print Back to top
News Article

The tunnel (next to the tunnel) that no one knows

One brings trains through the Rockies. The other has been delivering much-needed water for 80 years. 

My Facebook feed has a tendency to run rampant with advertisements and click-bait articles, but one piece making the rounds was worth the read.

The story, posted on a blog called Only in Your State, was about the Moffat Tunnel, a marvel of early 20th century engineering that appears to be a bit of secret.

Many people know about the Eisenhower Tunnel, the highest point in the Interstate Highway System. The Moffat Tunnel is lesser known, but just as important, the author writes.

From concept to total completion, it took 30 years to construct a railway to chug right under the Continental Divide, connecting travelers from Denver to Winter Park, Colorado, and beyond to Salt Lake City.

The Moffat water tunnel, partially lined with steel, can deliver up to 100,000 acre-feet of water annually.


Industrialist David H. Moffat Jr., a railroad guy and visionary who conceived the plan as a way to boost trade and commerce for the city and the West, once said of his project: “I had no ideas of greatness when I undertook the building of the Moffat Road. I wanted to do it for the good of the state and nothing more.”

David Moffat (1839-1911) spent an estimated 14 million dollars building the railroad to Rollins Pass.


Moffat died in 1911, long before his vision was completed, but the work continued. Workers dug through gneiss, granite and schist-filled mountain to build the rail line, while others built an access tunnel alongside the main one.

When the work was completed and the first train ventured through the tunnel in 1928, the service tunnel took on a new life.

The tunnel was partially lined and, in 1936, brought the first flow of water from the West Slope (where 80 percent of the state’s water originates) to the booming Denver metro area. For more details on the history, check out “A tale of two tunnels: How the Moffat Tunnel conquered the divide.”

The 6.2-mile Moffat water tunnel runs parallel to the famous railroad tunnel.


Workers lived in camps on each end of the tunnel and worked up to 90 hours a week. Twenty-six men lost their lives during the construction. For the surviving families of the workers, the tunnel represents a culmination of work and a monument to those who gave their time and lives to a cause that helped Denver become a growing city.

Workers pose for a photo in the Moffat water tunnel in this 1930 photo.


For a peek into that past, check out our story on Gloria Ryan, whose father worked as an electrical engineer on the tunnel project.


Of course, the effort had its share of funding issues, delays and ownership transfers. In 1996, Denver Water purchased the water tunnel to safeguard water supplies in the north system for future generations. Today, the 6.2-mile-long water tunnel is still in operation.

“The Moffat Tunnel has been a critical part of the water system since the Dust Bowl,” said Cindy Brady, water resources engineer. “It’s amazing how much vision the early planners had. More than 80 years ago they developed the Moffat Tunnel as clean, reliable water supply, making it a big part of the reason Denver is great today.”

The east portal of the Moffat water tunnel emerges from underneath the Continental Divide where it feeds into South Boulder Creek .