Stagnant floodwaters pose public health problem
Sunny skies returned to El Paso this week after Sunday’s monsoon storm that left parts of the city’s East Side submerged in floodwater. But water safety experts and city officials cautioned that still waters still pose a threat.
“(Standing water) could have some types of contaminants or debris beneath the surface that can cause injuries,” said Kristina Mena, a water safety expert and campus dean of the UTHealth School of Public Health in El Paso. “It’s best to avoid, and not wade in it, play in it or walk a pet through it.”
Standing water remained in some of the city days after the storm, including Album Park, where city crews pumped standing water from the mini lagoon that resulted from the downpour.
More than three inches of rain fell in an hour during Sunday’s storm.
Flooding is the second-deadliest natural disaster after heat waves, according to the Centers for Disease Control and Prevention. The flooding in El Paso streets Sunday carried off cars and saw water three to four feet deep, but caused no injuries, according to a city Fire Department spokesman.
Beyond the immediate impacts, floodwaters can carry water-borne pathogens, waste and pollutants.
Angela Mora, director of the City of El Paso Public Health Department, said stagnant water can host bacteria, viruses and parasites — all of which can cause diarrheal disease.
“Exposure to contaminated water can also cause skin rash, and tetanus wound infections. Contamination of wounds and lacerations in both humans and animals can trigger infections that can spread to other parts of the body,” she said.
Mora said another concern from standing water is mosquito breeding. She said homeowners should remove any items that might collect water, and work with vector control experts to remove mosquitos, and people should wear repellent and take other mosquito precautions.
Officials from El Paso Water said that any stormwater collected in the Rio Grande, a primary source of city water, can be treated by their plants.
“Our river water treatment plants can effectively treat any water that may have derived from stormwater runoff to meet or go beyond federal and state drinking water standards,” El Paso Water officials said in an emailed statement.
More rain could be in store for the Borderland.
Meteorologist Jason Grzywacz with the National Weather Service El Paso Forecast office said the storm on Sunday was a typical monsoon pattern, which occurs between late June through September.
“If anything, this storm itself wasn’t strong, it just sat in one place for a long period of time,” Grzywacz said.
The areas that got the most rain included Montana Avenue between Hawkins Boulevard and McRae Boulevard, which received 3.45 inches. Grzywacz said the current forecast expects a dry week through Thursday, with chances for an upcoming wet weekend.
But threats to the stormwater system don’t come just from rainy seasons, experts said, but the threat climate change poses by making rain storms stronger and more frequent.
Ben Hodges, an engineering professor at the University of Texas at Austin, called Texas thunderstorms “water bombs” that make it hard for cities to prepare for flooding.
“There’s so much water coming down in such a short period of time that removing that volume is very, very difficult, especially the costs to make that design for those, it’s just impractical. And so we don’t do that,” he said.
Hodges said three key problems face local stormwater utilities: many cities have aged infrastructure that isn’t up to modern standards; the United States is facing increased flooding from stronger storms because of climate change; and there are no answers for how more frequent flood waters could impact communities’ water quality.
“You’re washing sediments, you’re washing pollutants, you’re washing whatever’s in parking lots,” he said. “And that’s all going to go down into the runoff. So yeah, those are all issues that are huge and really not well answered.”
El Paso Water designs stormwater projects to capture and return rainwater based on a 100-year storm, or the rainfall totals that have a 1% chance of falling in the area. Using a 100-year storm is a recommendation from the Federal Emergency Management Agency.
Christina Montoya, the communications and marketing manager for El Paso Water, said that limited budgets mean that those standards are phased in.
“Designing projects to a higher standard results in a substantially more expensive facility and therefore higher fees,” Montoya said.
She gave the example that some projects would start with protection from a 25-year storm and then in subsequent phases move to a 100-year storm protection level.
“We’re still going to get through that initial set of projects where our stormwater system was just not given attention historically,” Montoya said. “We’re playing catch up, we’re trying to get as much done as we can.”
El Paso Water officials also said the arid area and mountain slopes contribute to the flash flooding, and falling rocks cause debris that needs to be cleaned out of channels. Montoya said maintenance and construction are funded by stormwater fees levied by the utility, although federal and state grants also provide money.
“The most challenging problem we have is to complete improvements while being mindful of the need to keep stormwater rates low based on public input,” officials said in an emailed statement.
Matt Bartos, an assistant professor in environmental and water resources engineering at University of Texas at Austin, said increased urban growth and older equipment compound the climate challenges.
“Stormwater infrastructure designed to handle historical rainfall regimes will fail to keep pace with demands imposed by future storms,” he said. “That’s not to say we’re totally doomed. There’s huge potential to transform our existing stormwater infrastructure to meet the challenges posed by climate change and other future stressors.”
Bartos said some of those changes are already underway as utilities incorporate green spaces to naturally clean the water before it gets flushed out of the cities and into waterways. He also credited innovations in “real-time” management that allow operators to wirelessly direct water flows by remotely controlled pumps and valves to “prevent flash floods before they happen.”
Bartos said that cities should start by studying the current system.
“We don’t know how much water is flowing through these systems at any given time, and we don’t know whether real-world stormwater flows match the numerical models used to design these systems,” Bartos said in an email. “As such, it is difficult to predict how real-world stormwater systems will react to current storm events — let alone future ones.”
Cover photo: Corina Ley, 18, ventures out with dog Capri into the inundated Album Park on Monday. The park remained under several feet of water from a storm a day earlier. (Danielle Prokop/El Paso Matters)