A distributed approach to the problem of flooding. "During dry times sensors conserve power, but when the water starts flowing, they crank up their data stream. This involves waking up a bridge-mounted digital camera and shifting from Bluetooth to higher-bandwidth Wi-Fi so GridStix can take part in processing photos of the rising river.

By tracking ripples and flotsam, the network can estimate flow rates — an economical alternative to ultrasound flow sensors — and relay a single number back to Met along with an update to local residents."