Pretty much every drop of the Colorado River
is owned by someone.
The river is actually overcommitted:
When the Colorado River Compact was drafted in
the 1920s, it was based on barely 30 years of
streamflow records that suggested an average
annual flow of 17.5 million acre feet past Lee's
Ferry. Modern studies of tree rings revealed
that those three decades were probably the
wettest in the past 500 to 1,200 years – and
that the natural long-term annual flow past
Lee's Ferry is probably closer to 13.5 million
acre feet, as compared to the natural flow at
the mouth of 16.3 million acre feet. This has
resulted in more water being allocated to river
users than actually flows through the Colorado.
I had heard that, but I didn't find the reference quickly, and I had to post. Didn't want to make unsubstantiated claims. Thanks for the follow-up. :)
As a result we've been in violation with a treaty with Mexico over the lack of promised water volume over most of that time as well. Again, too busy to find the link.