Earlier this week researchers from the University of California, Berkeley took to the Sacramento River to deploy a fleet of 100 mobile sensors to gather real-time data about the river. The Floating Sensor Project, as it's called, is hoping to replace traditional fixed water sensors with something that's able to provide information "at a level of detail not currently possible" — everything from water movement to the spread of pollutants. And because the sensors are mobile, they can also be easily deployed to monitor an emergency situation, such as an oil spill.

Each sensor includes a water-tight capsule complete with a battery and a GPS-equipped smartphone with a custom-built Android app, which sends information back to a lab every few seconds. Of the 100 deployed during testing, 40 were equipped with propellers that let them avoid obstacles and move around as autonomous robots. Once the testing is complete the sensors can simply be scooped up out of the water until they're needed again — and each time they enter or leave the water they're able to send out a tweet.

Right now the sensors cost a few thousand dollars each, but the team is hoping to reduce that by quite a bit as some units will inevitably be lost after being deployed in the field. Once that's sorted, they have some pretty high hopes. "We expect this to become an invaluable tool for the future management of a critical resource in this state and around the world," says associate professor Alexandre Bayen.