As the annual monsoons are set to bring rains to Arizona, Flagstaff and cities across the state often face an issue that seems somewhat strange in such a landlocked state: local and urban flooding.
Sections of Flagstaff and Phoenix often experience annual flooding events, but at the moment, predicting and managing such floods can be difficult, said Eck Doerry, a professor of Computer Science School of Informatics, Computing and Cyber Systems at Northern Arizona University.
Even gathering data on local flooding is expensive, with water gauge sensors costing as much as $50,000 to $100,000 a unit.
But that could be changing. A team of researchers led by faculty from NAU and Arizona State University, working with several other universities across the country, is collaborating with the cities of Flagstaff and Phoenix in the hopes of turning the basic street infrastructure into a flood monitoring system.
The project, called Flood Aware, hopes to take the traffic cameras normally used to detect vehicles at intersections and change the streetlights from red to green and turn them into flood detection machines, said Doerry, one of the researchers on the project.
“Our overall plan was, ‘Hey, I wonder if we can piggyback on all of the imagery already being taken in the city?” Doerry said. “We could add in some [artificial intelligence] and smart image processing to use snapshot images and be able to process them and say, ‘Hey, in this image the water is five centimeters high.’”
Using these cameras would greatly increase the amount and speed at which flood data could be gathered, Doerry said. That amount of real-time data would allow them to not only map flooding throughout a city as it is happening but also predict what areas may be flooded 20 minutes in the future.
To this end, the researchers have installed 10 cameras to monitor urban flooding with five placed around Flagstaff and five in Phoenix. Doerry said this also allows them to experiment with image quality to determine how detailed an image must be for their software to still be able to measure the water level.
A traffic camera doesn’t have to be very good to detect the shape of a car or a cyclist, Doerry said, but they have also found that even a place like Flagstaff has very sophisticated traffic detection systems.
“The way things are going, they don’t even sell low resolution cameras anymore, so just the cameras they’re replacing regularly are getting better and better,” Doerry said. “Our cute little city of Flagstaff actually has a fairly sophisticated network already. I was personally surprised by what they’ve got.”
This offers some big advantages to cash-strapped municipalities as most cities likely already have the infrastructure in place to track flooding, only needing the software to make it work.
Doerry said they have received some concerns about the 10 cameras they have installed from residents worried about privacy. But he said the cameras only take snapshots of the amount of water on the ground.
“They don’t swivel to point at your bedroom, they're just fixed. They point at the curb and that’s all they do,” Doerry said.
The team is also developing an app to be used by the public that could display the real-time flooding information and to help crowdsource yet more data.
First, the app will allow people to take photos of flooding around the city. That photo will then be uploaded into the same system to which their own cameras upload and provide one more data point to the system. That could be especially helpful if it is in an area without traffic cameras.
The app would then also allow the user to see a map of where flooding is occurring and the map of where, based on their modeling, the flooding may be occurring in 20 minutes or an hour.
“If you have a Flood Aware app, it could send people in flood-affected zones an alert saying, ‘Hey, it’s going to be flooding there real soon, you might want to move,’” Doerry said. “First responders could use it to position resources, sandbags, whatever.”
The researchers have a prototype of the app now, but Doerry said it will be released to the public later this year or early 2020, essentially in time for the next monsoon season.
The Flood Aware research comes in the wake of a study published late last year that concluded urban flooding is a widespread and growing issue but is often overlooked by researchers and government officials alike.
In that study, researchers from the University of Maryland and Texas A&M University surveyed public servants and private sector workers who managed flooding in 350 cities and 48 states. What they found was over half of respondents said their communities experienced moderate or large urban floods.
They also found that largely, issues like poor or aging drainage systems are ignored for other worries, leading researchers to refer to urban flooding as America's “hidden challenge.”
“Flooding is by far the most expensive natural disaster that we have in the U.S.,” Doerry said.
In part, that is because unlike other natural disasters, flooding is fairly common and widespread, being an issue even in landlocked and otherwise fairly dry places like Flagstaff.
Doerry added that this is only likely to worsen over the next few years as climate change creates more severe weather events.