The Gunnison Tunnel: why the Montrose valley is farmland

Drive past the orchards and cornfields around Montrose and it is easy to assume the valley was always green. It wasn’t. The Uncompahgre Valley is dry, and the Gunnison River runs right next door, but it runs at the bottom of a gorge too deep to reach. The water and the fields are separated by a wall of rock called Vernal Mesa.

So crews bored straight through it. Between 1905 and 1909, workers dug the Gunnison Tunnel, a passage about 5.8 miles long that pulls water from the Gunnison River and carries it under the mesa to the South Canal and out across the valley. The conditions were brutal: water, gas, cave-ins, and a fractured fault zone. When it opened it was counted the longest irrigation tunnel in the world, and President William Howard Taft came to Montrose to dedicate it on September 23, 1909.

That tunnel is why the farms are here. More than a century later it still moves Gunnison water to tens of thousands of acres of Uncompahgre Valley cropland, the backbone of the local ditches and headgates you will run into as a newcomer. In 1972 the American Society of Civil Engineers named it a National Historic Civil Engineering Landmark. It is a landmark you mostly can’t see, hidden in the rock under your feet. To read the full story, start with History Colorado’s Gunnison Tunnel page.