Sunday, August 9, 2009

overdue - some discussion of the link between water and growth from the Joint City/County Water Study

Finally found some time to post on this. The committee discussed the report "Integrating Land Use Planning with Water Resources and Infrastructure Technical Paper" that can be downloaded here. My comments to the committee on the paper are also available on the study website, but I'll briefly discuss them here as well.

My two main points of discussion on the paper were in regards to the concerns expressed over operation of the Central Arizona Groundwater Replenishment District (CAGRD) and their discussion of the Interim Water Service Policy established by the city manager in late 2007.

On the CAGRD, there has been extensive discussion recently about the physical disconnect between the replenishment activities of the District (whereby they recharge renewable water supplies to offset pumping by water utilities or subdivisions that are enrolled in the district) and the actual groundwater pumping that leads to the replenishment obligation. The point I wanted to make is that, in the way the CAGRD was created it was not really meant to replace pumped water in an aquifer with recharged, renewable water. As with much of the Arizona Groundwater Management Act (GMA), it was a water accounting system designed to ensure that accounts remain in balance within each Active Management Area (AMA). Without going into whether this was a good or bad thing, it is what our legislators decided to do to accommodate population growth and further development within AMAs. The problem we have encountered with it is not that the pumping is occurring far away from the recharge, but that the program has been much more popular than many originally envisioned, so the quantities of water being pumped have become pretty large, resulting in considerable water level drawdown in some locations. Here's what I said in my comments to the committee:
Due to constraints on land availability, complexity of hydrogeology, and cost considerations in implementing recharge that directly mitigates effects of pumping it will prove to be very difficult in practice.
... seeking to routinely and effectively mitigate pumping effects by suitable location of recharge will result in many situations where it would simply make more sense to utilize the renewable supplies for the new development, rather than enroll in the CAGRD, because the renewable supply will be brought close enough to make its use economical vs. the cost of recharge. If such policies were strongly pursued the need for the CAGRD would be virtually eliminated, but at considerable cost.

While doing more to use recharge for mitigation of pumping effects is a good idea in theory, I think it's pretty difficult to implement in practice.

As for the "interim water service policy" my opinions on this have been explored in the blog in the past (see this post). I really have a problem with this being referred to as a policy:
I believe it is overly optimistic to refer to this as a “policy” when in reality it is more of an acknowledgment that no policy has ever existed. The former city manager acknowledged as much in an interview published in the Daily Star last October. Until there is an actual policy to evaluate requests for extending water service to new development the City is entirely at the whim of outside forces that will determine how water is supplied to new developments outside of the obligated service area.

I also reiterated my earlier statement that one of the criteria for agreeing to serve a new development should be a requirement that the effluent from that development be available to the city to augment our reclaimed water supplies.

The future linkage between water supplies and growth is a critically important issue for the future of Tucson and other cities like it that have seen their available water supplies stretched almost to the physical limits by rapid growth in the recent past. There should be more exciting discussion on this issue when the committee tries to reach agreement on this portion of the Phase II report.

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