Shared from the 8/27/2019 San Antonio Express eEdition

Watering limits loom as aquifer drops amid heat


So far, the San Antonio area has escaped outdoor watering restrictions this summer, but that could change next month.

In the past several weeks, the Edwards Aquifer has dropped sharply and is approaching the level that triggers the first stage of cutbacks.

July and August have been extraordinarily hot and dry, like a “flash drought,” said Karen Guz, the San Antonio Water System’s conservation director. There’s been less than a half-inch of rain here since June 30. For the year, rainfall is almost 6 inches below average.

Guz and Paul Bertetti, the Edwards Aquifer Authority’s director of aquifer science, said plentiful rain earlier in the year helped stave off water restrictions, and the current aquifer level is still higher than normal.

The record-breaking 16.86 inches of rain that fell on San Antonio in September gave the aquifer a boost — then July and August undid it.

“Yes, there’s a significant drop,” Bertetti said. “The drop is fairly typical for times when it’s summer and there’s been no rainfall.”

The EAA will institute Stage 1 pumping restrictions when the 10-day rolling average of the J-17 well, which monitors the Edwards below San Antonio, falls below 660 feet. On Monday afternoon, it was hovering slightly over 666 feet. It has been dropping by about 3.5 inches a day recently.

In Stage 1, those with pumping permits, such as SAWS, are required to cut their pumping by 20 percent.

For SAWS customers, that would mean outdoor watering is limited to one day a week, before 11 a.m. or after 7 p.m. on a designated day based on the last number of the street address.

Guessing if and when the aquifer will reach 660 feet is only moderately easier than filling out an accurate NCAA basketball tournament bracket.

“It’s tough to say,” said Bertetti, who has noticed the aquifer isn’t falling quite as fast now as it was a few weeks ago.

Guz said she expects Stage 1 to hit in late September if there’s no rain and customers’ water use continues apace.

“The amazing thing in San Antonio, as soon as we do get a good rain, we’ll see (usage) drop immediately from one day to the next,” she said.

During a 12-day stretch this month when high temperatures reached triple digits every day, SAWS pumped more than 3 billion gallons of water in the first 10 days, including nearly 319 million gallons in a single day.

Still, the utility’s total water use for the year is lower than average because of rainfall in earlier months, Kuz said.

She sees little impact to landscapes if outdoor watering is restricted.

“By the time we reach fall, the days are shorter, it won’t be as hot and the landscape need for water is lessened,” she said.

The grass may be getting dry and crunchy, Kuz said, but as soon as there’s a good rain, it will green up again.

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