Farms, factories and water utilities that pump from the Edwards Aquifer will now have their permitted withdrawals cut 30 percent instead of 35 percent, after the agency that regulates the aquifer moved the San Antonio Pool back to a less severe drought stage. San Antonio’s water system, however, still told customers on Oct. 21 that Stage 3 watering rules were in effect.
The Edwards Aquifer Authority, the groundwater district that manages the aquifer serving about 2.5 million South Central Texans, said in an Oct. 16 press release that it declared a return to Stage 2 of its Critical Period Management Plan, effective Oct. 5. The pool covers Medina and Bexar counties and parts of Atascosa, Caldwell, Guadalupe, Comal and Hays counties.
The date is retroactive because of a data revision. The authority said the U.S. Geological Survey provided revised discharge measurements for Comal Springs on Oct. 16. On Oct. 5, the reported daily mean flow at Comal Springs was 169 cubic feet per second, the standard measure of how much water a spring is releasing. That produced a ten-day rolling average of 151 cubic feet per second, above the Stage 2 threshold. The ten-day average at Index Well J-17, the Bexar County well that serves as the region’s official gauge, was 640.2 feet above sea level, and the San Marcos Springs average was 89 cubic feet per second.
The Stage 2 reduction applies to every Edwards groundwater permit holder authorized to pump more than three acre-feet a year. An acre-foot is about 326,000 gallons. That includes industrial and agricultural users and utilities that sell Edwards water to customers. The release says the cut is 30 percent of each holder’s withdrawal amount, applied according to the number of days the stage is in effect, and permit holders must report pumping to the authority monthly.
The change follows a quick swing in the other direction. The Dispatch reported Sept. 24 that the authority had returned to Stage 3, with a 35 percent cut, effective Sept. 20, when the J-17 ten-day average was 639.9 feet. The Oct. 5 effective date for Stage 2 puts the two stage changes about two weeks apart.
The authority’s release does not address San Antonio’s watering rules, and it says the authority does not enforce lawn watering or other general limits; municipalities do. The San Antonio Water System is a separate body. Its website banner on Oct. 21 showed the J-17 well at 639.2 feet, updated that day, and said Stage 3 watering rules were in effect. As the Dispatch reported in September, SAWS’s Stage 3 begins under city ordinance when the J-17 average falls below 640 feet.
Whether SAWS lifts its Stage 3 watering rules is the next decision to watch. The authority said it will keep tracking the J-17 well, the Uvalde Pool’s J-27 well and flow at the Comal and San Marcos springs.