Previously I alluded to efforts by the development community in Southern Arizona to derail plans by the city and county to allocate up to 10,000 acre-feet of treated sewage for environmental uses in the region. These folks have decided that the process for allocating this water to environmental uses wasn't sufficiently rigorous and risks the loss of a significant portion of renewable water that can be used to support future population/economic growth. They sent a letter to both the County Board of Supervisors and the City Council saying (among other things) that: "[e]ffluent is a highly reliable, locally available component of our region’s renewable water supply portfolio" and "the proposed IGA does not contemplate replacement of these entitlements, which are needed to promote and support regional economic growth."
Whoa! Wait a minute. I didn't know that this water was surreptitiously taken from some magical bucket of water reserved to support future growth in the region? Admittedly, that is one possible use for that water - not to be turned into potable water to be provided to future residents of Tucson (unless state law changes, that's currently illegal), but to be recharged to generate storage credits that permit future pumping of groundwater to supply homes and businesses. But this water belongs to the entities that generated the effluent (the city and the county), who are free to allocate it in ways they believe will best benefit the region. Clearly there was some discussion within the community when the decision was made to set aside this water for environmental restoration. I don't remember any similar discussion when the decision was made to wipe out 90% of the riparian habitat in the region so that water could be provided for the growth of the community.
But the current reality is that most of that water is currently wasted (this links to a fairly large pdf, but go to page 6 - the table shows where the water goes from the treatment plants - the row titled AZPDES discharge is what is dumped in the river; some of that generates storage credits, presently, but most of it does not and quite a bit of it actually flows out of the AMA). It does support some pretty degraded habitat along the Santa Cruz River, downstream from the sewage treatment plants and when the upgrades of those plants are completed in the future, the quality of that water will actually support some aquatic life. But for now, some of that water is used to supply the reclaimed water system (replacing groundwater pumping for turf irrigation), a portion of it recharges naturally along the rivercourse and earns credits for various entities, but over 20,000 acre-feet of that water provides essentially no benefit to the region.
Fortunately, both the city and county governing bodies chose to continue with plans to implement their agreements for dedicating this portion of the water to environmental uses. But I suspect this battle is not entirely over, because parties wishing to use this water for environmental projects still have to go to the city and county to be approved to take it. Many of the arguments being made will be made again, especially because water supplies will almost certainly be tighter at that point than they are now. But when it comes to finding ways to restore lost riparian habitat (and especially the water needed to do so) I think this is the most promising avenue to realize that objective. It's not elegant, it's not simple. But it may just be effective.