The Phoenix City Council today agreed to pay the Gila River Indian Communities $2 million as part of a deal to leave 40,000 acre feet of the Indian Communities’ Colorado River water in Lake Mead this year. The state of Arizona, the federal government, and the Walton Family Foundation also are contributing. From the city staff report to the council:

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This is a big deal along a number of dimensions. The first is simply the water in Lake Mead. This is part of a broad effort to reduce withdrawals from the over-subscribed reservoir. Still much work to do here, but evidence of progress can be found in the latest Bureau of Reclamation forecast, out yesterday (pdf), that shows Mead ending the “water year” six feet above a year ago.

Second reason it’s a big deal: outside money. The Walton Family Foundation’s contribution shows a growing role for philanthropy in going beyond governmental institutions in working the problem. This was much discussed last week at the Martz Conference I attended last week at the University of Colorado. I’m pretty sure a million dollar contribution to Colorado River system conservation is unprecedented? (Please chime in in the comments if you know of others of this sort or scale.)

The third is the partnership of the city, state, and federal government. Having those levels of government (polycentricity, y’all!) pulling in the same direction to leave water in Lake Mead is worthy of note.