Comal Springs have only stopped flowing once in recorded history. Could it happen again?

Justin Horne, Weather Authority Meteorologist / Reporter

Mary Claire Patton, Digital Journalist

The impacts of the current long-term drought are far-reaching.

Jacob’s Well is closed, San Antonio Water System has stepped up enforcement of water usage and Canyon Lake is nearing an all-time low. These are all bad situations, but it could become even more critical if Comal Springs stops flowing.

Comal Springs is a series of approximately 15 major and minor springs within Landa Park on the northwestern edge of New Braunfels. The springs, known for producing crystal-clear water, are the source of the 3.25-mile-long Comal River that flows southeast into the Guadalupe River. Comal Springs is a historically stable water source in an area where water supplies can be scarce. It’s why people have flocked to the area for millennia. In addition, they support a unique population of plants and animals, some of which are protected by the federal government. Should the springs cease to flow, it could affect endangered, threatened, or petitioned-to-be-endangered species that call the aquifer home.

“The Comal Springs stopped flowing for several weeks in 1956 (June 13 to Nov 3), following several years of successive drought in the early to mid-1950′s,” explained Paul Bertetti, senior director of Aquifer Science Research and Modeling at the Edwards Aquifer Authority.

“In order for the flow at Comal Springs to be in danger of stopping, we would have to lower water levels in the Aquifer another 10 feet or so,” said Bertetti. “It is thought that flow from the springs ceases at a water level of about 619-620 feet mean sea level.”

This would be the level reported at the J-17 well and what you see us report on KSAT 12. As of Friday, the Edwards Aquifer was measured at 627.5′ at the J-17 well.

“In 1956, there were some contributing factors that diminished spring flow at Comal Springs. There was at least one very large production pump brought online that summer,” said Bertetti. “This pump was very close to the springs and probably caused local levels to fall, thus cutting off flow earlier than it might have without the pumping.”

Water levels dropped all the way to 618′ in 1956 for several days, causing the springs to stop flowing. Using modeling, the Edwards Aquifer Authority can play out worst-case scenarios when it comes to Edwards Aquifer levels.

“The statistical model suggests we could possibly reach — fall to 620 feet in early September if we do not have rain,” explained Bertetti. “That is, we would have to be below the 10th percentile in precipitation between now and then.”

So the short answer to the “could it happen again” question is “probably not.” But the fact that we are in the range of it being even a small possibility is a distressing idea.

“We saw low water levels during the most recent drought of 2014. Water levels were about 626 feet, and flow at Comal dropped to the 60s (that is about 67 cubic feet per second or cfs) that year,” said Bertetti. “Low flows also occurred in 1990 (cfs values in the 40s) and in 1984, which was a hard year. In 1984, flows decreased into the 20s (cfs) at Comal Springs when water levels decreased to 623 feet at J-17.”

“Unlike 1984 and 1990, we have Critical Period Management (CPM) restrictions in place,” explained Bertetti.

Critical Period Management is how the Edwards Aquifer Authority curtails pumping during drought periods. It’s meant to help sustain the aquifer and springflows.

“Flow at Comal Springs has been in the high 70s (cfs) the past few days, while water levels at J-17 are 628-627 feet. Thus, we would hope that as additional CPM restrictions are enabled (should water levels continue to fall), we might delay the appearance of very low flows at the springs,” added Bertetti. “If we can buy a few weeks, we would hope that September precipitation could help to raise water levels and spring flow.”

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