Assessment of earthen levee stability for management and response: A NASA-DHS-California Dept. Water Resources collaboration
Abstract
Radar remote sensing of the Sacramento-San Joaquin Delta, the largest estuary in the western U.S. (over 2500 km2), and its levee system provides an opportunity for NASA Applied Science to aid the CA Department of Water Resources (CA-DWR) in monitoring and emergency response. The delta contains over 1,500 km of earthen levees, supports about 2.5 million acres of agricultural land, and serves as a main water supply for 23 million California residents. Many of the reclaimed islands are 10-25 feet below sea level, sit atop compressible peat and organic clay soils, and are surrounded by levees only 1 foot above the once in a century flood elevation threshold. Land subsidence in the delta can be attributed to a variety of factors, including: aerobic oxidation of soils, soil compaction from drainage, wind erosion, anaerobic decomposition, dissolved carbon fluxes, floods, seismic events, and even rodent burrowing. Interferometric Synthetic Aperture Radar (InSAR) is an established technique to measure surface displacements and has been used to map large-scale subsidence. The demonstration of earthen levee monitoring is a recent development that has been greatly furthered by the emergence of new instruments such as NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR). UAVSAR is an L-band airborne sensor with high signal-to-noise ratio, repeat flight track accuracy, and has a high spatial resolution (7 x 7 m) that is necessary for detailed levee monitoring. The adaptability of radar instruments in their ability to see through smoke, haze, and clouds during the day or night, is especially relevant during disaster events, when cloud cover or lack of solar illumination inhibits traditional visual surveys of damage. We demonstrate the advantages of combining InSAR with geographic information systems (GIS) datasets in locating subsidence features along critical levee infrastructure in the Delta for 2009-2016. The ability to efficiently locate potential areas of instability will also be automated into GIS tools for the CA-DWR, who have oversight of the Sacramento-Delta levee system, that will help to bolster their current ground-based monitoring programs and to aid emergency response during a flood or earthquake event.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMNH43D..07A
- Keywords:
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- 4306 Multihazards;
- NATURAL HAZARDSDE: 4335 Disaster management;
- NATURAL HAZARDSDE: 4337 Remote sensing and disasters;
- NATURAL HAZARDSDE: 4352 Interaction between science and disaster management authorities;
- NATURAL HAZARDS