Engineers from the University of California, Berkeley, sent a fleet of 100 smartphone-equipped floating robots down the Sacramento River to demonstrate the next generation of water monitoring technology, promising to transform the way government agencies monitor one of the state’s most precious resources.
The Floating Sensor Network project offers a network of mobile sensors that can be deployed rapidly to provide real-time, high-resolution data in hard-to-map waterways. Having a high volume of sensors moving through the water can shed light on processes that are influenced by how water moves, such as the spread of pollutants, the migration of salmon, or how salt and fresh water mix.
Monitoring the state’s water supply is critical for the general public, water researchers, and government agencies, which now rely upon costly fixed water sensor stations that don’t always generate sufficient data for modeling and prediction. Such a flexible system could be critical in the event of an emergency, including a levee breach or oil spill. The sensors could be thrown into action from a dock, shore, boats, or even helicopters.
The launch in Walnut Grove marked a milestone in the project. It was the first time researchers deployed their full arsenal of floats, each equipped with GPS-enabled mobile phones encased in 12-inch-long watertight capsules marked with fluorescent tape. The researchers wrote specific programs to run on the open source platforms used in the robots and on the smartphones.
Every few seconds, the phones in the floats transmitted location data back to servers at Berkeley Lab’s National Energy Research Scientific Computing Center (NERSC), where the data was assimilated using a computer model called REALM (River, Estuary and Land Model). Information was processed to create a map that allowed researchers to track the devices on their computer monitors.
Although the sensors in the test were set up to monitor the speed of water currents, the researchers said the floats could be equipped with sensors for a variety of measurements, including temperature, salinity, or a contaminant of interest. Of the 100 floats in the fleet, 40 were autonomous devices fitted with propellers to help them move around obstacles or targeted areas.
The Floating Sensor Network’s fleet of robots includes prototypes with advanced capabilities, including models that can dive below the surface of the water, versions equipped with salinity sensors to measure the water quality in rivers, and versions with depth sensors that can map out the shape of the channels in which they float.
The floating sensor network has been tested in collaboration with the U.S. Department of Homeland Security and the U.S. Army Corps of Engineers to assess water discharge downstream from broken levees. The researchers are also planning a deployment to monitor the ecosystem of Lake Tahoe in the coming months.
