San Antonio Report
by Lindsey Carnett
Laptops, cellphones, the occasional Bird scooter and almost 2,000 apple snails were among the items found sitting on the bottom of the San Antonio River during the latest cleaning efforts conducted earlier this week.
The City of San Antonio’s Public Works Department, in collaboration with the San Antonio River Authority, drained and cleaned parts of the San Antonio River as part of its biannual maintenance. The cleanup was condensed and rushed as workers raced to get ahead of this week’s arctic blast, said José Salazar, operations manager of water operations for the Public Works Department.
As a part of this work, river authority staff relocated native fish species downstream and removed invasive species that were upstream, which included almost 2,000 apple snails, said Shaun Donovan, the river authority’s manager of environmental sciences.
The snails, native to South America, are a popular home aquarium species first found in the downtown San Antonio River in October 2019, which likely was an illegally dumped pet. They can quickly reproduce, laying egg clusters that can contain up to 1,500 eggs. Apple snails are a unique threat to the San Antonio River and the species that call it home due to their ability to eat and deplete freshwater vegetation very fast, Donovan said.
“As they eat that aquatic vegetation, it can lead to erosion and it can lead to loss of habitat for native species,” he said. “Aquatic vegetation has really good water quality improvement characteristics and capabilities, so it’s kind of an ecosystem-wide impact from this particular invasive species.”
Despite the large yield of apple snails, which surprised river authority staff, Donovan said he believes the situation is still under control, and thanked volunteers and staff for continuing to dispose of the snails as they find them. The 1,971 removed apple snails were mostly confined to the upper part of the river’s main channel, he added.
“I think we’re doing a really good job of controlling them,” he said. “The biggest thing we want is to prevent the spread downstream.”
That brings the total of apple snails that were removed to about 10,000 over the last year, Donovan added. Efforts to remove them will continue as they have without escalation at this time, he said. Residents can learn more about apple snails and the river authority’s efforts to get rid of them here.
The San Antonio River Authority keeps track of how many apple snails it has seen and removed from the San Antonio River via a dashboard on its website.
Courtesy / San Antonio River Authority.
Staff from the river authority staff and public works department also worked hard to remove invasive fish species from the river, Donovan said. City workers were trained on how to identify what species of fish they encountered and to sort them accordingly via a virtual training seminar, he said.
Roughly 200 city employees worked from 6 a.m. to 6 p.m. Friday, Saturday and Sunday on the river cleanup, Salazar said.
Along with cleaning the river, the integrity of its channels and floodgates were checked, Salazar noted, which is important to flood control efforts that help prevent downtown from being washed away in a severe rain event, such as the Flood of 1921.
“We started cleaning the River Walk in the mid-1980s, and drain the river about every two to three years depending on the amount of rain we have in the past years. This gives us the opportunity to to remove sediment, any sand or clay, that collects in the river channel.
San Antonio Public Works employees scrape debris from the riverbed in the San Antonio River.
Credit: Brenda Bazán / San Antonio Report
Months before the draining efforts start, city staff works to coordinate with stakeholders such as businesses along the river, Salazar said. Draining parts of the river takes about 12 hours. The river’s levels are controlled via their floodgates, which are operated via computers by city staff, Salazar noted. The river is drained gradually over that period to prevent a rush of water from flooding areas downstream, he said.
After the draining, workers can drop in equipment and send in staff, Salazar said. Sometimes small cranes are needed to help drop larger equipment into the channels, he said. Following the cleanup, it takes about 48 hours to refill the parts of the river that were drained, Salazar said.
This latest cleanup was scheduled to run from Jan. 12 through Jan. 21, and included draining the San Antonio River Main Channel from Josephine Street to East Nueva Street and from South Alamo Street to Lone Star Boulevard.
“What happened was, we had to speed up the cleaning due to the weather,” Salazar said. “Our time was already budgeted for a whole week, so we didn’t get extra overtime or anything.”