Last week’s heavy rains can be measured in more ways than inches and feet. They can also be measured in weeks.
The 2 to 5 inches of rain that fell in parts of the Hill Country amounts to a few weeks’ worth of water use trickling into Central Texas’ main reservoirs. That in turn means the most restrictive Central Texas water rules in living memory probably won’t take effect until some time in November, instead of as early as mid-October.
“It’s not a drought buster, but it’s definitely welcome,” Lower Colorado River Authority General Manager Becky Motal said in a statement.
The region’s main reservoirs, lakes Buchanan and Travis, are 33 percent full, according to the LCRA, which manages the lakes. The LCRA had predicted the lakes would dip below 30 percent full some time in October. When they hit a threshold just under 30 percent, the region will have surpassed the last measurement to consider the current drought to be the worst on record, surpassing the epic drought of the 1950s.
Entering the “drought of record” means additional water restrictions for much of the region.
Many Central Texas cities and water-distribution districts buy their water from the LCRA. When the current drought is declared the worst on record, the LCRA will tell its customers to cut back water use 20 percent from 2011 levels.
The requirement will affect communities differently. Some have already cut back. Some have not. Austin, thanks to its water-conservation policies, largely will be exempted from the 20 percent curtailment.
Even so, Austin water managers plan to enact additional restrictions when the region enters the drought of record. For instance, for 21 of the past 23 months, Austin has limited automatic lawn-watering systems to one-day-a-week use. On designated watering days, automatic sprinkler systems are allowed to operate between midnight and 5 a.m. and between 7 p.m. and midnight. When the LCRA declares the drought the worst on record, Austin will limit watering to one time a week, during either the morning or evening, according to the city’s water utility.
It’s not clear exactly when that will happen, assuming the area sees little rain in the coming weeks, though LCRA calculations point to some time in November. Water from the recent rains is still flowing into lakes Buchanan and Travis. By Tuesday, the combined storage of Buchanan and Travis had reached 657,642 acre-feet, “up from 637,300 acre-feet early Friday,” according to an LCRA release. The rains added the equivalent of the water used by 6,780 typical Central Texas homes use in a year.
But that rainfall is a relatively small drop in the Central Texas bucket. Lake Travis was full in spring 2010, a time when Buchanan was nearly full as well. Before the recent rains, they were 31.7 percent full. As of Tuesday afternoon they were 32.7 percent full.