Sunday, October 6, 2013

Austin Dry in as Little as 2 Months New Calculation

Why Our Conservation Schedules Were Too Little & Too Late

October 6, 2013

The parched earth after record 8 year droughtE

Discounting Gov. Perrys bizarre attitudes and inaction with regard to the drought, our pre determined trigger points for different levels of conservation were based on the worst drought on record in 1951.  At that time Austins population was 132,000.  The current population is 843,000, a 6.38 times increase.  In addition, there were no water hungry industries, like the semiconductor chip fabs that inhabit Austin now.  A study in the late 2000s revealed that an average chip fab plant used enough water to supply a city of 50,000 people.  Austin has 14 of these plants, which consume even more water than the plant that was studied, because the wafer size was 6, and now the standard is 8.  The amount of water needed to rinse a wafer increases exponentially, not linearly.  But for the purposes of this essay, I will use the 50,000 people per plant estimate, so the chip fabs add 14 x 50,000, or 700,000 people.  That makes Austin functional population around 1.5 million.

With lake reservoirs at about the same level in 1951 as now, 600,000 acre/feet, with only 132,000 people, the threat of running dry was distant.  People used less water then than now, but for simplicity, I will use the current outrageous usage of 168 gallons/per person per day. So, the extra  hypothetical extra 700,000 people use 168 gallons/per/capita/day = 700,000 x 0.325 = 227,000 acre-feet. (The conversion from gallons to acre feet is 1.0 million acre-feet = 0.325 gallons.)  Therefore, the total usage per day is  the total of the actual number of people plus that used by the additional usage by the hypothetical people represented by the extra 227,000 acre-feet per day.

Another factor to be considered is that the two reservoirs, are the only source of water for not only Austin, but the additional people that have filled up Travis county as suburbs that didnt exist in 1950.  The current data indicates that there are 1.7 million people in the county.  Almost as many people in the county outside the Austin city limits, as there are in within the city.  Therefore, the total number of people dependent of the two reservoirs, is the previous calculation including the hypothetical people, plus 1.7 million less 843,000, or 857,000 added to the 1.7 million = 2.58 million.

Today the 2.58 million times the daily usage of 227,000 acre-feet per day of usage = 5.85 million acre feet/day, divided by 30 days per month resulting in only 1.95 months until we run dry. 

Had the trigger point estimates took into account the population increase we should have been at level 3 conservation in 2009, and level 4 early in 2011.  If those conservation measures were carried out, we would not be in the critical state we face today. With only about 14 months if you believe the State web site which says that we have 600,000 acre feet, and states that lake Travis is 30% full (which would be 260 feet of water, when it has been a plainly visible empty pit for almost 2 years.  So, with that bold face lie to foster confidence that lake Buchanan has what the web site states, my guess (and it is just a guess because the real data is no where to be found) that Buchanan has only 50% of the stated value.  That would give Austin only 4 months until we run dry.  Keep in mind that the inflows for 2013 have been almost as low as 2013, or about 30% of normal.  That amount is neutralized by loss to evaporation and the fact that 10% of the water at the bottom is unusable because of sediment.  The forecasters including all of the meteorologists and climatologists see no change in the near future (up to 5 years) so we are using up a fixed amount of water.


Morris Creedon-McVean