With Eric Kuhn’s help, I found a (nearly) full Colorado River Basin reservoir!

Dillon Reservoir, June 15, 2022

When Eric and I converge on a meeting, there’s always the “Are you gonna bring a bike?” conversation.

This week it’s the Getches-Wilkinson Center’s Annual Colorado River conference, and the bike ride was a loop around Denver Water’s Dillon Reservoir, on the Blue River.

It’s nearly full. The creeks feeding it were running. There was a cool breeze.

In the midst of the sturm und drang, it was lovely.


  1. On Denver Water’s website it notes the earthfill dam is over a mile long, possibly explaining why in 1963, “…[t]he entire town of Dillon and a hydroelectric plant were relocated to build the dam, which diverts water from the Blue River Basin through the Harold D. Roberts Tunnel under the Continental Divide into the South Platte River Basin”.
    That Dillon Reservoir is 93% full of water diverted across the Continental Divide reminds me of New Mexico State Engineer Steve Reynolds’ pithy observation about “water flowing uphill to money”. And brings into question whether our current situation is due to the “limited vision” of engineers, as some like to claim.

  2. This is SOP for Denver Water. They maximize diversions on the east slope first before tapping into the west slope. They catch a lot of Breckenridge flack with large drawdowns. None of that water is destine for the Colorado River Basin. The only benefit is that it leads towards more bypass flow. The South Platte takes the hit first. Greg

  3. Greg,
    Yes, the headwaters of the Colorado are west of the Continental Divide, not at the Continental Divide. Sorry for creating confusion.

  4. Every State has some quirk:
    Colorado’s is they have lot’s of water basin diversions going back to the late 1800’s.
    The SCOTUS decision Wyo v. Colorado that set some of the foundational law of the river was about water basin diversion. Colorado Western Slope water going east instead of west.
    Kansas V. Colorado and Colorado V. Nebraska were effectively settled using Colorado River water diverted to Kansas and Nebraska.
    So the full pretty lakes & reservoirs in the mountains of Colorado (Dillon, Grand Lake, Granby) are to make sure that water gets to the east. Ironic isn’t it.

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