Christian Claudel at the King Abdullah University of Science and Technology outside Jeddah is working on a UAS system that could give cities between 30 minutes and 2 hours of warning, as well as predicting the flood’s path.
Flash floods are quick and deadly. At least 13 people died when a surge hit parts of Saudi Arabia earlier this month. Two years earlier, 123 were killed when thunderstorms dumped rain over arid land to the east of the Red Sea port of Jeddah, hitting the city with no warning.
Existing forecasting models are good at predicting roughly when an area might experience the right mix of conditions to create a flash flood, but they can’t say precisely when or where a flood will strike.
The goal is to launch a swarm of about 10 UAS to automatically monitor a potential flash flood. They will drop disposable wireless sensors across the region at risk. If the sensors meet floodwater they will be carried away on the current, sending out a simple signal which the drones can track. The UAS relay the sensors’ changing positions back to a central database, which builds up a model of floodwater flow.
“The sensors are made of printed circuits on paper, which reduces the cost of the device,” says Claudel. The printed sensors act as location tags, pinging a unique ID number to the drones over a short range. This is much cheaper than using dedicated sensors with their own communications systems, which may never be recovered. He will describe the system at the International Conference on Unmanned Aircraft Systems in Atlanta, Georgia, at the end of May. Claudel has meetings set up for June with the city authorities in the Saudi capital Riyadh about starting a trial of the scheme.
Kristen Rasmussen, who studies flash flooding at the University of Washington in Seattle, says it would be really useful to combine the UAS system with existing models that take account of terrain and how the water moves. “That could be very powerful,” she says, adding that such floods are a problem all over the world, from Venezuela to the US Southwest. A flash flood in Colorado in 1976 killed 176 people. But she warns that the social aspect of prediction is equally important: getting the message out and persuading people to pay attention to it.
“Unless the information is used to get the word out to people, even the most advanced technology is not much use,” she says.
“These are fast-moving, violent events that are hard to predict,” says Burrell Montz of East Carolina University in Grenville. “This would be awesome if it works.”
Source: New Scientist