Along the Mirror Lake Scenic Byway.

Duchesne Tunnel

What is it?
The Duchesne Tunnel is a six-mile long 10-foot diameter concrete-lined horseshoe-shaped rock tunnel that runs from the Duchesne Diversion through the Uinta Mountains to the Provo River.

Why was it built?
The Provo River Project and the Association have water rights in the Duchesne River and Little Deer Creek, and the Duchesne Tunnel was built to convey that water from the Duchesne River to the Provo River. Much of the water eventually is stored in Deer Creek Reservoir where it is made available to the Association’s shareholders.

When was it built?
Construction on the Duchesne Tunnel began in 1948, but was halted in 1951 at the outbreak of the Korean War. It resumed in 1953 and was completed in 1954. One team of workers started construction at the proposed inlet of the tunnel, and at the same time another team started at the proposed outlet, planning to meet in the middle. It has been reported that with only transits and slide rules, engineers were so accurate in their surveying that when the two ends met they were only inches off. The tunnel is so straight that one can peer inside and see the other end, six miles away!

How big is it?
The Duchesne Tunnel is six miles long and 10 feet in diameter. It has a capacity of 630 cfs. The highest flows in the Tunnel are during the spring runoff.

What is the Association’s responsibility?
It is the Association’s responsibility to keep the Tunnel clear and running freely in order to divert water to the Provo River, and to maintain the associated machinery and structures.(*)