Settlers of European heritage arrived in the Uncompahgre River Valley after the Ute tribe was ordered to reservation lands in Utah by the federal government in 1881. The pioneers staked out properties and established covenants. The Uncompahgre River carried the usual annual melt from the San Juan Mountains through today's Ouray, Montrose, and Delta Counties toward its confluence with the Colorado River near Grand Junction. But the settlers' crops required more water than the river or irrigation ditches could bring. Engineers assessed the failed farms and abandoned villages in the wake of the Uncompahgre Valley's over-settlement and looked east of Montrose to the Black Canyon, cut by the nearby Gunnison River. They drilled the Gunnison Tunnel to bring the snowcap melt from the Continental Divide's western slopes to the Uncompahgre Valley, creating one of the Rocky Mountain region's most fertile valleys. The tunnel, completed in 1909, was the biggest irrigation project up to that time.