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Update on water supply – scary numbers you won’t see anywhere else

Based on numbers from LCRA, the total non-agricultural water use + evaporation in 2012 was 529,137 (just barely lower than the 540,000 acre-feet in 2011). Evaporation was lower (due to the relatively less severe weather in 2012), municipal use was down only slightly (probably because of less lawn watering – again weather related) but non-agricultural use was up, especially industrial use. Regardless of the details from one year to the next, it is clear that we are now, in general, using and evaporating more than half a million acre-feet each year, exclusive of any agricultural water use whatsoever.

As of this morning, we have 691,000 acre-feet left (728,000 less 37,000 that is unreachable by our treatment and distribution system). This is almost exactly 240,000 acre-feet less than a year ago (968,000), despite getting above-average rainfall of 35 inches in 2012, and just-below average rainfall in 2013 in Austin. (Actually Austin totals are arguably irrelevant except as a broad indicator of likely rain totals upstream from Mansfield dam). The fact is that recent trends with respect to inflows show that even when Austin is doing okay with rainfall, the area just to our west is not.

So, the updated arithmetic appears to be:

If we take into account all of the rainfall we’ve had over the past year, and project that same amount of rainfall going forward, we have 34.5 months of water left.

If we assume no rain going forward, and use 2011 use and evaporation numbers, we have 15.35 months left.

If we assume no rain going forward, and use 2012 use and evaporation numbers, we have 15.67 months left.

By the way, I think it is worth noting that, if we had not had above-average rainfall last year, we’d be in an even deeper crisis. Supplies in early 2012 were down around the 850,000 level. If 2012 had been a “drought” year, we could easily be 150,000 acre-feet (and consequently several months) closer to running out of water. It is in this context that I believe even considering releasing 125,000 acre-feet or more for growing rice is irresponsible and that option should be taken off the table – permanently.

Here’s a link to an article on the San Diego desalination facility I’ve mentioned in a previous post, and which is now under construction. It appears to be a public-private deal, and it was awarded the “Water Deal of the Year” as noted in the article. I would note that at $2100 per acre-foot (the approximate price quoted in the article), that would be about $6.50 per thousand gallons. Here is the current Austin retail water rate schedule for comparison, which ranges from $1.25 per thousand to $12.25 per thousand, with a middle tier rate of $5.60. I would say $6.50 for a dependable long-term source compares very favorably with our current rates for a completely undependable source.

Bottom line:  desalination is no longer prohibitively expensive relative to other options or relative to what we currently charge for water in Austin.

Bottom line #2:  Whether we use desalination or some other solution, we’d better start working on a big infrastructure project to add to our water supply.  We’ve already waited too long.  How close do we have to get to EMPTY in order to startle us into waking up and taking action?  Just asking.

Yes, I know.  Maybe it’ll rain.  And maybe’s not good enough.

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