Record rains a stress test for Waco-area drainage systems

In general, the systems worked well, but the repeated heavy rain also revealed some unknown problems and highlighted some previously known problems, leading to localized flooding in some places and even some sinkholes.

A pair of sinkholes opened over storm sewers in Waco this month as a result of heavy rain events, said Roger Glick, who directs watershed protection for the city of Waco. Some business owners also noticed high water on streets and vacant lots, while others didn't see those problems even though the city had reports near their businesses.

Last month's record 15.28 inches of rain was especially difficult because much of it came in repeated heavy downpours, limiting the water's ability to soak up.

“We had a lot of rain in a short amount of time, so the topsoil became saturated and the rest went into the runoff,” Glick said. “And that happened several times, over and over again, so the storm sewer system was put to the test.”

Waco, Bellmead and Hewitt charge property owners drainage fees to create a dedicated funding stream for the operation, maintenance and construction of stormwater infrastructure. Waco's rate, first implemented in October 2021, is now $6.31 a month for most homeowners and raised $12.3 million over the past two years. Waco also has $11.7 million remaining in various bond issues for stormwater and drainage projects.

Bellmead's fee, now $4.18 a month for most homeowners, began in January 2023 and has raised nearly $206,000 so far. Hewitt's fee is $4.35 per month for residential properties. All three cities charge higher rates for commercial properties based on the size of the property's impervious area.

Officials said some of its storm drainage problems known or previously disclosed in May could be fixed quickly, but others would take longer, including the two sinkholes in Waco.

One opened June 13 at Baylor Avenue and 10th Street near Baylor University. The other opened June 3 on North 12th Street near Columbus Avenue Baptist Church.

Both initially involved minor leaks at joints between storm sewer components.

“Here near Baylor, we had a sewer that went under the street,” Glick said. “One joint didn't fit well and repeated heavy rain events kept forcing water through the leak, so the joint gave way.”

He said leaking rainwater interacting with the dirt under the street led to a hole.

The city covered the sinkhole, about 1.5 feet wide and 5 to 6 feet deep, with a metal plate and used a robot to check other joints in the nearby storm sewer pipe .

“We found several other joints that will also need to be repaired,” Glick said.

Your team will do further checks to determine the extent of the problem and then rank the sinkhole with other drainage issues and prioritize repair or renovation.

At 12th and Barnard streets, a section of storm sewer composed of pipes made of brick had a similar problem.

“We will have to check the entire brick pipe to verify its condition,” Glick said. “But there are fairly extensive brick pipe sewers in New York that are over 100 years old that are quite useful to this day. So it's possible that not all of those in Waco need to be replaced.”

Near the 12th Street sinkhole, the city had three concrete pipes, 5 feet in diameter and about 12 feet long, lined up to replace damaged portions of the brick pipe.

In October, another sinkhole formed on a residential lot at 2514 Gorman Ave., over a section of storm sewer the city didn't even know about, said Kendra Anderson-Davis, the city's real estate asset manager from Waco.

“This storm sewer collapsed last year around Thanksgiving and Christmas,” Anderson-Davis said. “We didn't know, so we didn't have an easement. When crews checked, they found the storm drain was running right under the house.”

Anderson-Davis said the city moved the family living in the home into a hotel immediately, bought the home at fair market value and helped the family find a new home.

On the corner of Gorman Avenue and 25th Street, about 75 meters from the sinkhole, Luz and Adan Gonzalez want to open an ice cream parlor next to a store they already own. Between the shop and the sinkhole there is an undeveloped lot.

Around May 22, the storm drain near the sinkhole backed up significantly and there was several inches of water on Gorman Avenue between 25th and 26th streets, they said.

Adan Gonzalez took video of a car stopped in deep water down the street from the store.

“It flooded the lot next to the store, but no water got into the store,” he said Thursday.

Despite some dramatic examples of problems, storm sewers did their job in most parts of the city and carried runoff into creeks, streams and rivers, Glick said. But there were a few places where drains overflowed and streets flooded briefly.

“The Waco storm sewer system is designed to carry what we call a five-year storm, a major storm that might come once every five years, or that has a 20 percent chance of happening in any given year.” , Glick said.

Most of the storm drains worked properly, he said.

“In some places in the city, there are known drainage problems that acted (in May) as we thought they might. Other issues or new issues were rediscovered that we didn't know about before,” Glick said.

He said his team has a list of known drainage problems in Waco.

“We're adding some new issues after May,” Glick said. “We'll review them, reclassify them, and then start to consider how best to address each issue. In some cases, it was just a matter of removing the debris to clear the storm drain and everything went back to normal. In others, there are issues larger ones that will require design and engineering before repairs can begin.”

Debris clogs near Stewart Drive and 27th Street, near Gorman Avenue and 31st Street and near 1300 Wooded Acres Drive were quickly resolved.

Glick said a slightly more extensive problem happened near 318 Bluebonnet Circle, where tree roots became a storm drain. He said there are also traffic jams and undersized sewers.

He also said there had been localized flooding near 1103 N. Fifth St., an undeveloped lot. But the owner of a nearby midwifery clinic said her staff only work on certain days at the clinic and she had never seen the streets filled with water.

In Bellmead, Public Works Director Craig Rice, who started with the city in April when the rains began, said his city saw drainage backups south of Texas State Airport. Technical College and north of the former railway goods yard. Both are places where the city has long known problems with slow drainage. Elsewhere, the Bellmead storm drainage system worked well, he said.

“On Bellmead Drive, there were times when the water was running several inches deep during a storm,” Rice said. “But within 30 minutes to an hour, two at the most, the road was cleared of water.”

In low-lying areas of Bellmead, however, it sometimes took a day or two before the waters completely dissipated, Rice said.