In March 2015 the National Aeronautics and Space Administration (NASA) began working with the U.S. Geological Survey (USGS) and the University of Oregon (UO) to test new remote sensing technology that can measure streamflow conditions from space. However, before the technology can be deployed, it must first be checked with real-time water surface measurements. This “calibration” check is done by attaching the sensor to an airplane and flying it over the Willamette River during different times of the year. While the plane was airborne, scientists boated the Willamette River measuring the corresponding water level. Additional instruments were also deployed to further compare the plane measurements to the actual water surface. This technology is called SWOT (Surface Water Ocean Topography) and the satellite will be ready for launch in 2020.
NASA’s SWOT and AirSWOT Missions
The SWOT mission will help hydrologists gain a better understanding of the Earth’s water resources by using radar technology to take repeated, high-resolution elevation and discharge measurements of oceans and waterbodies from a satellite (http://swot.jpl.nasa.gov/). But before the satellite can launch, NASA must calibrate and validate the SWOT instrument using a plane-mounted version known as AirSWOT (https://swot.jpl.nasa.gov/airswot/). With SWOT technology, hydrologists, working in fresh water systems, will be able to calculate changes over time in the world’s lakes, oceans and rivers. This information will inform a wide range of socially relevant issues, like better understanding of water availability for farms and communities and improved ability to map flood hazards.
AirSWOT ALONG THE WILLAMETTE RIVER
During the spring of 2015, three AirSWOT flights traveled along the Willamette River. The USGS and UO simultaneously collected measurements of water surface elevations that will enable the NASA to fine-tune their instruments.
BENEFITS OF TECHNOLOGY
Along with collecting concurrent data, USGS also installed 25 pressure transducers to continuously record water levels through May 2015. In addition, both USGS and UO deployed technical teams to survey water surface elevations and channel bathymetry (depth) throughout the Willamette Valley. These data can be used to develop and calibrate hydraulic models for evaluating inundation, water depths, and sediment transport for various flow and restoration scenarios. The models can also be useful for generating inundation maps for different low-flow or high-flow scenarios, which can ultimately provide critical information to river users, residents, and floodplain managers. The bathymetric datasets from 2015 can also be compared with earlier datasets to evaluate changes in bed elevation, which could signify potential for increased flood hazard or impacts to floodplain habitat and connectivity.
Rose Wallick, Geomorphologist
U.S. Geological Survey
2130 SW 5th Ave.
Portland, OR 97201
Mark Fonstad, Associate Professor
University of Oregon, Dept. of Geography
Eugene, OR 97403-1251