From flood to drought: Utilizing sar to assess the status of levees and aqueducts

During 2013–2017, the State of California experienced a major drought that impacted water management practices, water delivery, and groundwater extraction, any of which had the potential to impact the critical infrastructure used for water conveyance. The use of synthetic aperture radar interferometry (InSAR) and multi-polarization SAR images to monitor levees and aqueducts in California during the period 2009–2016, which overlapped the drought, is described. The study used data acquired with UAVSAR, an L-band airborne SAR instrument operated by NASA. An overview is given of the methodology adopted to measure subsidence rates of ≥ 2 mm/yr of earthen levees and aqueduct embankments. Results are presented showing the most significant identified hazards to the structures from ongoing land use practices, natural hazards, and groundwater withdrawal.