Your Watershed / Watershed Facts / Transmountain Diversions

Not All Water Flows Downstream

In the West, it is commonly known that water flows downstream unless its flows upstream towards money. We would add “money and people”. This adage is true in the state of Colorado. About 80% of our population lives on the Front Range while about 80% of the state’s water is on the Western Slope. Beginning in the 1930s, transmountain diversions that move water from west to east, were built to help meet the demands of the more populous Front Range.

Today, Colorado has 24 major tunnels that move water from western Colorado to eastern Colorado under the Continental Divide. Two of the five largest diversions are located within the Roaring Fork Watershed. The Boustead Tunnel moves water from the Upper Fryingpan River and Hunter Creek drainages to Turquoise Lake near Leadville. The Twin Lakes Tunnel diverts water from the Roaring Fork River headwaters to Twin Lakes on the other side of Independence Pass. During spring and summer, as tunnels move water and fill reservoirs, as much as 40% of the water in these headwaters areas is not flowing downstream.

As water demands increase, the Roaring Fork Watershed’s transmountain and in-basin diversions will play a major role in Colorado’s water future. 


 Find out more about the diversions in the Roaring Fork Valley:





Transmountain Diversion Facts:

  • Two of five largest transmountain diversions in Colorado are in Roaring Fork Watershed
  • 38% of Roaring Fork headwaters above Aspen diverted on average, each year 
  • 41% of Fryingpan headwaters above Meredith diverted on average, each year


Colorado Transmountain Diversions

Map provided by Office of State Engineer 

Click here to enlarge map

Contact Us

Roaring Fork Conservancy

PHONE: (970) 927-1290

PO Box 3349
Basalt, CO 81621

22800 Two Rivers Road
Basalt, CO 81621

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