Deformation Monitoring for the Assessment of Sacramento Delta Levee Performance

The Sacramento Delta levee network plays a vital role in supporting the United States' largest agricultural production and the municipal water supply for millions of people. Beyond the potential for earthquake-induced failure, performance monitoring of the levee system on the network level and the assessment of potential distress levels are needed for the maintenance and rehabilitation of this system. In this case, critical deformation needs to be assessed especially in view of the levees age, sea level rise, and ongoing subsidence due to the decomposition of the peat foundation layer. The work presented herein describes the remote sensing of a levee section deformation with time. The levee section is located on Sherman Island, CA, and monitoring was conducted in situ by GPS, in addition to remote sensing by airborne synthetic aperture radar and satellite systems. Coupled deformation/seepage numerical analysis of the levee section is performed using PLAXIS. The numerical model included characterization of the unsaturated-saturated zones and the peat foundation layer. Key parameters of the peat layer were synthesized from published data to provide baseline assessment for the current condition of the levee system in view of the measured rate of deformation.