Wastewater gushes from a broken pipe into a sinkhole at 8414 Quintana Road in December 2016. Credit: Camille Garcia / Rivard Report

Gabriel Cantu always had an uneasy feeling about the sewer line connection built below Quintana Road in the spring of 2015.

At that time, the former inspector for the San Antonio Water System was assigned to observe construction work on a sewage line replacement in the 8400 block of Quintana Road on the city’s Southwest side.

On Dec. 4, 2016, a sinkhole formed at the site of that connection that took the life of off-duty Bexar County Sheriff’s Deputy Dora Linda Nishihara, who drowned in the pit of rushing sewage after her 2007 Pontiac Grand Prix plunged in on that rainy night.

“That connection should have never been allowed,” said Cantu, 42, now an engineering inspector for the City of San Marcos. “I don’t know what else to say. It’s just bad construction.”

In Cantu’s view, shortcuts on both the engineering and construction of a temporary connection between old and new pipes led to the leak. Sewage escaping from the line eroded the ground beneath the asphalt, which crumbled into the newly formed pit below.

His inspection reports are among the documents contained in a combined wrongful death and personal injury lawsuit filed last month by Nishihara’s family and two other plaintiffs, Anthony Villarreal and Claudia Milay Silva. Villareal and Silva escaped with their lives after their vehicles also plunged into the hole, which stretched across the entire two-lane road.

The suit filed in the 285th Civil District Court alleges that engineering firm CDM Smith and construction contractor S.J. Louis Construction of Texas, both SAWS contractors, were negligent in designing and building a temporary underground connection that leaked and ruptured. The suit also alleges that SAWS breached its duty to carefully monitor the project and mitigate any hazards.

Representatives of CDM Smith denied the allegations in a legal filing and in a statement emailed to the Rivard Report.

“We strongly deny any wrongdoing in the event and have the greatest sympathy for the individuals and families affected,” Julia Burleson Forgas, CDM Smith’s vice president of communications, wrote in the email. “In accordance with our policy, we do not provide specific comments about ongoing litigation.”

Through two spokesmen, SAWS officials declined to comment on what caused the break, also citing the pending lawsuit. In a legal response to the suit, SAWS outside counsel Ricardo Cedillo denied the allegations while arguing that SAWS’ status as a government entity gives it immunity from certain legal claims. 

Executives with S.J. Louis Construction did not respond to a phone message and email seeking comment. As of Tuesday, the company had not yet submitted a formal legal response to the suit filed April 4.

No trial date has yet been set.

The incident occurred on a sewer line that was being upgraded as part of a $1.1 billion overhaul of SAWS’ sewer system that’s been underway since 2013. The municipally owned water and sewer utility serves 1.7 million people in the San Antonio area.

In the weeks following the incident, SAWS officials briefed City Council members and the news media on the work that was going on prior to the collapse but never revealed exactly what caused the sinkhole.

The suit alleges that the sewage leaks first began at a junction box, a cube of concrete, that was connected to a temporary pipe made of corrugated metal 54 inches in diameter.

A connection between sewer lines below Quintana Road. Credit: Courtesy / San Antonio Water System

The allegations rely in part on an affidavit from L. David Givler, a licensed engineer hired by the plaintiffs as an expert witness to review plans, construction documents, photos, and samples of pipe that SAWS stored after the event.

Givler wrote that the break stemmed from a series of engineering errors. CDM Smith’s engineer, Damien Herrera, the only defendant named individually in the suit, designed a connection that sent sewage flowing through the temporary pipe more than eight times faster than it should have under state sewer standards, causing the pipe to vibrate and wiggle, Givler wrote.

The temporary pipe’s connection to the junction box used a frame of plywood supported by sandbags. Givler wrote that this connection couldn’t handle the intense forces caused by the flowing sewage, which began leaking and scouring out the dirt that was filled in around the connection to provide additional support.

During the construction work, Cantu’s job was to make sure that crews were following plans approved by Herrera.

In the inspection reports, Cantu repeatedly mentions his efforts to get the crews with S.J. Louis to fill in the hole around the connection with a more supportive type of material called flowable fill, rather than the dirt that they ended up using.

“I notified [the contractor] that I am concerned with backfilling this tight area around shoring, he said he would [place] flowable fill here under roadway,” Cantu wrote in one daily construction report dated March 17, 2015.

In another report two days later, Cantu wrote that an S.J. Louis employee told him that they used dirt to backfill the hole, justifying it because the connection was only temporary.

“The obvious question to me from Day One is how long is temporary?” said attorney Daniel Sciano, who is representing Nishihara’s brother and two adult children in the lawsuit, in a telephone interview with the Rivard Report. “It was a hidden time bomb waiting underneath the streets until it failed.”

A year and a half elapsed between June 1, 2015, when the asphalt over the connection was repaired, and the night of Nishihara’s death, said Aaron Valadez, a lawyer who works with Sciano.

In interviews with the Rivard Report, Cantu said the desire to get through this phase of the project with a temporary connection that would be later replaced may have led SAWS engineers to go along with inadequate designs.

He said that he tried to raise these and other issues with his supervisor and a manager in his department at SAWS, to no avail.

“I feel my recommendation simply got brushed aside because of time and money,” Cantu said. “If certain people were in the room with SAWS above me…I don’t think they would have just let it brush aside. They would have said hell no, we’re not allowing that. But I’ve got a chain of command, and I’ve got my hierarchy.”

Citing the pending litigation, SAWS officials declined to comment on Cantu’s statements about how the temporary connection was approved, and his claim that the issues he raised were brushed aside.

SAWS officials noted that utility executives reached out to Nishihara’s family following her death. After the collapse, SAWS President and CEO Robert Puente spoke to members the family at the scene, SAWS vice president of communications Gavino Ramos said. Puente and SAWS Chief Operations Officer Steve Clouse also attended Nishihara’s funeral, Ramos said.

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Cantu left SAWS in mid-2016 to pursue an opportunity in the private sector before going back to inspection work in San Marcos.

He said he saw several practices on the Quintana Road job that he’s never seen before or since in his nearly 10-year career as an inspector and total 21 years in the construction field.

Hand-drawn engineering plans for a pipe connection that used corrugated metal pipe, plywood, and sandbags. Credit: Courtesy / San Antonio Water System

One was the use of corrugated metal pipe, typically used in drainage culverts, in a sewage job, which typically requires fiberglass reinforced pipe, high-density polyethylene, or concrete. He also said he has never seen a plywood-and-sandbag connection or a hand-drawn engineering plan submitted for approval.

Cantu said he still feels “horrible” about what happened but isn’t sure what he could have done differently at the time.

“I feel like I could have maybe made a bigger stand, I don’t know how,” he said. “I made it pretty clear.”

Sciano contends that some of the responsibility does belong to SAWS.

“SAWS owns the premises, SAWS has the piping, SAWS has the knowledge of what was going on,” Sciano said. “They have [professional engineers] … They’re a sophisticated owner. They’re not like you and me.”

Brendan Gibbons

Brendan Gibbons

Brendan Gibbons is the Rivard Report's environment and energy reporter.