The Flood Alert System uses radar, rain gauges, cameras and modeling to indicate whether Houston’s Brays Bayou is at risk of overflowing and flooding the Texas Medical Center.
Rice University civil engineering professor Philip Bedient is an expert on flooding and how communities can protect themselves from disaster. He directs the Severe Storm Prediction, Education and Evacuation from Disasters Center at Rice University.
Starting late Sunday night, the Houston area began experiencing major rainfall. By Monday afternoon, rainfall totals in some parts of region had exceeded 15 inches in 24 hours. It’s an event many are comparing to to 2011’s Tropical Storm Allison, which devastated the region.
Bedient is hoping to make those type of flood events less devastating. He designed the Flood Alert System – now in its third version – which uses radar, rain gauges, cameras and modeling to indicate whether Houston’s Brays Bayou is at risk of overflowing and flooding the Texas Medical Center.
In an interview with Urban Edge editor Ryan Holeywell, conducted after the Memorial Day floods of 2015, he said more places need those types of warning systems.
Ryan Holeywell: What’s wrong with the way communities get flood warnings today?
Phil Bedient: You see what happened in Wimberly. It’s atrocious that they didn’t have enough warning. The National Weather Service only issues warnings by county. It’s too general. We have a specific flood warning system for the Texas Medical Center, but we need more.
RH: Why don’t we have a flood warning system like the one you designed everywhere?
PB: We’ve tried over the years to get it expanded. We have one in Sugar Land. We have one in the Clear Lake-Clear Creek area. But I think there are great opportunities to build this out for the city proper. It wouldn’t be the whole city, but the major water sheds.
Part of the problem is the county refuses to issue warnings, and they leave it to the National Weather Service. It keeps them from getting into issues of liability.
It’s a wonderful tool. We’re trying to carry the banner for it into San Marcos and Wimberly. What happened there is inexcusable. They got absolutely no warning it was coming. People were killed who should have never been in harm’s way. This technology is too simple to build. For the cost of one city truck, we can build this system.
RH: How did you create the Texas Medical Center’s warning system?
PB: They were tired of just watching Brays Bayou come up, and they needed more advanced time to deal with things. They came close with a 4.5 inch rain fall. It was really scary. The Texas Medical Center CEO at the time, Richard Wainerdi, called me and said ‘we’ve got to get this more high tech.’
I had just come from some meetings in Oklahoma, where I ran into a guy who was an expert on rainfall radar, which first launched in the mid 1990s. I told the medical center about this brand new technology. We started working with it, and to make a long story short, it worked very well. We went from there, and the medical center funded us to develop the system.
Shortly thereafter, in 2001, Tropical Storm Allison hit, and it worked beautifully. We predicted everything very accurately. FEMA gave us some money to further advance the system – we called it FAS2 – and around 2010 we expanded it to become FAS3. It’s probably monitored well over 150 storms.
RH: How does it work?
PB: The radar data gets sent to a private company in Oklahoma to calibrate it and measure the rainfall. It’s fairly sophisticated. We then load that data into our models and we can predict the elevation of Brays Bayou.
All the data from the radar, the cameras and the gauges are packaged into a website. It’s a lot of information in one place, where a single decision-maker – a CEO or a security official – can easily make sense of it and make a call based on that information. We spend a lot of time training the medical center personnel on our system and getting feedback on what they want to see.
We have a traffic light system on the web page to warn people. When we estimate Brays Bayou will rise above a flow rate of 24,000 cubic feet per second, it turns red. We were at 28,500 on Memorial Day. They locked down the medical center before that. I helped them design the system that allows them to lock 75 doors and gates around the Texas Medical Center. It shuts down like it’s a castle.
RH: How does the Memorial Day flooding here in Houston compare to major flooding in the past?
PB: Everyone wants to compare it to Tropical Storm Allison, but this is much smaller. They used helicopters to get 650 people off the roofs in the medical center back then. At the time, it was the worst urban flood in the U.S. history.
RH: If we had unlimited resources, what could Houston do to protect residents from flooding?
PB: There’s some low hanging fruit. There are low water crossings, near the Galleria, at 1-45, on the U.S. 288 bridge. They all go underwater when there’s 6 to 8 inches of rain. Everybody knows it. They need to watch these hot spots carefully with cameras and send out emergency vehicles to block them to traffic. It’s common sense.
At the next level, they need to go into the watersheds that are contributing to flooding and build models like the FAS3 and make them available to the public. The problem is the public gets flood alerts for the whole county. That doesn’t tell them anything. It’s a bunch of numbers. Nobody understands what 6 inches of rainfall in 3 hours means. You need a simplified system that’s communicating to the public whether their area is in trouble.
People get all these county-wide alerts, and they quit paying attention. Harris County is 1,700 square miles. We’re giving people the same alerts in Tomball that we’re giving people in Clear Lake 50 miles away. I don’t want that kind of prediction.
RH: Whenever Houston has flooding, we hear about people who get stranded in cars in flood water. Why doesn’t the “turn around, don’t drown” message seem to resonate?
PB: During Tropical Storm Allison, there were 22 deaths. Twenty of them were on the road in cars. That’s one of the reason I’m in business. It’s difficult for normal people to comprehend the sheer madness of water out of control. In Wimberly, the water rose 40 feet in one hour. You can’t wrap your head around that. It’s coming from far away, and it’s a quiet killer.
This story was originally published by The Urban Edge, a blog by the Kinder Institute for Urban Research.