Radar interferometry offers new monitoring approach for critical flood
control infrastructure
Abstract
Aging flood infrastructure systems will need to be closely monitored as
metropolitan areas globally face increasing inundation risk from sea
level rise. To augment traditional ground survey, synthetic aperture
radar (SAR) is shown to efficiently quantify elevation change along
earthen levees with continuous spatial coverage. The study area,
California’s Sacramento-San Joaquin Delta, has an exemplar earthen levee
system that protects the region from flooding. We investigate evidence
of settling from historic levee breaks and small-scale subsidence
features with a vertical velocity map and time-series of cumulative
displacement derived from data acquired by the UAVSAR (Uninhabited
Aerial Vehicle Synthetic Aperture Radar) L-band SAR, during 2009-2015.
Comparison between radar and lidar maps (2007 and 2017) show that
typical laser elevation surveys can miss subsidence features in the
presence of normal maintenance activities. Historic levee break sites
show more stable conditions due to the nature of repairs, and can be
monitored using the SAR time series product. SAR information helps
monitor the efficacy of repairs and targeted improvements to decrease
the risk of levee breaks. In light of the upcoming NASA-ISRO SAR
satellite mission, for which UAVSAR is the prototype, detailed
monitoring will be attainable for levees worldwide.