Scientists and engineers from NASA and the U.S. Geological Survey (USGS) have successfully developed and tested a drone-based system designed to provide detailed maps of river flow rates. This innovative technology, named the River Observing System (RiOS), promises to enhance the monitoring and understanding of river dynamics, critical for water resource management, environmental protection, and public safety.
Rivers play a crucial role in supplying fresh water to communities and farms, supporting wildlife habitats, transporting goods, and generating electricity. However, they can also carry pollutants and pose flood risks, making accurate and timely monitoring essential. The collaboration between NASA and USGS aims to address these challenges by leveraging advanced drone technology equipped with specialized instruments.
The RiOS system, approximately the size of a gallon of milk, includes thermal and visible cameras for tracking water surface features, a laser altimeter, navigation sensors, an onboard computer, and a wireless communications system. In 2023, the team conducted field tests along the Sacramento River in Northern California, with a final round of tests scheduled for fall 2024.
“Deploying RiOS above a river to evaluate the system’s performance in a real-world setting is incredibly important,” said Carl Legleiter, USGS principal investigator of the StreamFlow project. “During these test flights, we demonstrated that the onboard payload can be used to make calculations – do the analysis – in nearly real-time, while the drone is flying above the river. This was one of our top-tier goals: to enable minimal latency between the time we acquire images and when we have detailed information on current speeds and flow patterns within the river.”
The team utilizes open-source software combined with proprietary code to produce flow field maps from a series of images. These maps reveal water surface velocities by detecting subtle temperature differences carried downstream.
“You might think that we need to see discrete, physical objects like sticks or silt to estimate flow velocity, but that’s not always the case,” Legleiter explained. “Using a highly-sensitive infrared camera, we detect the movement of subtle differences in the temperature of water carried downstream.”
This technique, initially developed for planetary exploration, helps track the static surface of icy terrains or moving water surfaces, ensuring the safety of spacecraft while gathering valuable data. “Icy surfaces present challenging visual conditions such as lack of contrast,” said Uland Wong, NASA lead of the StreamFlow project. “Our technology can precisely track the static surface of icy terrain while flying over it or a moving surface like water while hovering above it.”
To prepare for the field tests, NASA built a robotics simulator to run thousands of virtual drone flights over the Sacramento River, using flow fields modeled by USGS. These simulations help create intelligent software that selects optimal drone routes and ensures efficient battery use.
The next step is to make the system more autonomous, allowing real-time flow calculations to guide the drone's flight path. “Does the drone drop down to get better resolution data about a particular location or stay high and capture a wide-angle view?” Wong posed. “If it identifies areas that are flowing particularly fast or slow, could the drone more quickly detect areas of flooding?”
Currently, USGS operates thousands of automated stream gauges and fixed cameras to monitor river flows across the country. “Drones could enable us to make measurements in so many more areas, potentially allowing our network to be larger, more robust, and safer for our technicians to monitor and maintain,” said Paul Kinzel, StreamFlow co-investigator at USGS. “Drones could help keep our people and equipment out of harm’s way in addition to telling us how the environment is changing over time in as many locations as possible.”
This collaborative effort between NASA and USGS represents a significant advancement in river monitoring technology, offering new tools to manage and protect vital water resources.
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