A Very Dry Decade on the Colorado
Posted on | November 7, 2009 | 5 Comments
With the 2009 “water year” just completed, it’s time to take stock. The decade just completed, 2000-2009, is the driest 10-year period in the Colorado River Basin in the record, according to preliminary data in the latest draft of the Bureau of Reclamation’s Colorado River Annual Operating Plan, a compendium of past data on the river and plans for the coming year:
Provisional calculations of natural flow for the Colorado River at Lees Ferry, Arizona, show that the average natural flow since calendar year 2000 (2000-2009, inclusive) is 11.933 maf (14,719 mcm), the lowest ten-year average in over 100 years of record keeping on the Colorado River.
Recall that the Colorado River Compact assumes 16.5 million acre feet (maf) average flow on the river, divided 7.5 maf for the upper basin states, 7.5 maf for the lower basin states, plus 1.5 maf for Mexico. For the last decade, the river has averaged just 72.3 percent of that amount.
Related posts:
- What Really Happened on the Lower Colorado in 1905?
- 20-year Average
- Stuff I Wrote Elsewhere, Colorado River Edition
- Climate Change and the Colorado River
- Colorado River Dry
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Comments
5 Responses to “A Very Dry Decade on the Colorado”
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November 7th, 2009 @ 10:28 pm
[...] This post was mentioned on Twitter by jfleck, Linda Rockwell. Linda Rockwell said: RT @jfleck The last decade has been the driest 10-year stretch on record in the Colorado River Basin: http://tinyurl.com/yb9hx95 #water [...]
November 7th, 2009 @ 11:22 pm
Has that been broken down into precip, evap and abstraction contributions?
November 8th, 2009 @ 8:36 am
Daniel -
I haven’t seen the underlying numbers.
But to clarify what they include, it’s a preliminary version of the Bureau’s annual “natural flow” calculation:
http://www.usbr.gov/lc/region/g4000/NaturalFlow/current.html
It is an attempt to estimate what the flow at Lee’s Ferry (the key measuring point on the Colorado) if the various dams and diversions were not there.
November 8th, 2009 @ 10:00 am
lower natural flow is exacerbated by more intensive extraction (to the LIMIT), and higher evap (hotter)
Time to “go aussie” — they quantify rights based on annual flow, with percentage shares intact….
May 1st, 2010 @ 3:42 pm
[...] answer to the question asked in the title of this post, right? The last decade is the driest 10-year stretch since record keeping began on the Colorado River. Of course Lake Mead has dropped because of “drought”, [...]