Farms, factories and water utilities that pump from the Edwards Aquifer are back under the deepest cut in the aquifer’s drought plan: a 35 percent reduction in their permitted withdrawals, up from 30 percent. The Edwards Aquifer Authority, the groundwater district that regulates the aquifer, declared a return to Stage 3 for the San Antonio Pool in a news release dated Oct. 21, five days after it announced a step back to Stage 2.
On Oct. 16, the authority announced a return to Stage 2, effective retroactively to Oct. 5, after the U.S. Geological Survey revised its Comal Springs discharge figure. Five days later, the Oct. 21 release reversed that move and put the pool back in Stage 3. It is now the latest notice on the San Antonio Pool on the authority’s news page.
The San Antonio Pool covers Medina and Bexar counties and parts of Atascosa, Caldwell, Guadalupe, Comal and Hays counties, according to the release. The authority said the change rests on falling water levels. On Oct. 21, the daily high at Index Well J-17, the authority’s benchmark well in San Antonio, was 639.2 feet above mean sea level. That produced a ten-day rolling average of 639.9 feet, which the release says is below the threshold for Stage 3. The Oct. 16 release had listed the well at 640.2 feet.
Spring flow, the second measure the authority watches, was close to the earlier figures. The release put the ten-day average at Comal Springs, in New Braunfels, at 152 cubic feet per second, and at San Marcos Springs at 95. The Oct. 16 release listed 151 and 89. One cubic foot per second is roughly 450 gallons a minute.
The cut 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, so that threshold is just under a million gallons annually. The release says the group includes industrial and agricultural users as well as water utilities that pump from the aquifer for their customers. The 35 percent reduction is applied to each holder’s authorized amount according to the number of days the stage is in effect, and all affected holders must report their pumping totals to the authority every month.
The authority also drew a line around what the declaration does not do. It said it does not enforce lawn watering or other general water limits beyond curtailing withdrawals from the aquifer, and that residents who get water from a public system should follow their provider’s directions. The San Antonio Water System’s website showed Stage 3 watering hours and an aquifer reading of 638.7 feet on Oct. 26.
The pool has now moved between stages repeatedly in about a month. The Dispatch reported a Stage 3 return in September. The Oct. 16 release then moved the pool to Stage 2 retroactive to Oct. 5, after the U.S. Geological Survey revised its Comal Springs discharge figure. Five days later the authority reversed course.
The lag between the aquifer and the rest of the state’s water picture is wide. The state’s reservoirs were 71.9 percent full on Oct. 26, according to Water Data for Texas, a state-run tracker. The aquifer’s index well, by contrast, sits below the line that triggers the harshest pumping limits in the authority’s plan. The authority ties each stage to those well and spring readings, so the 35 percent cut stays in force until they recover enough for it to declare another change.