Assessing levee stability with geometric parameters derived from airborne LiDAR

A methodology to assess levee structural integrity using high resolution airborne Light Detection and Ranging (LiDAR) data is investigated for a 16 km reach of the Sacramento River within the Sacramento–San Joaquin River Delta (California). Levee geometric parameters (levee crown width, height and water and landside slopes) were extracted from 0.5 m resolution LiDAR derived digital ground models. Deviation of these parameters from minimum levee design standards was used to calculate a levee stability index. Stability maps were generated and those areas that did not meet USACE geometric shape standards were identified. Results show that 2 out of the 4 geometric parameters do not meet the minimum value required in 48% and 43% of profiles on the east (urban adjacent) and west (farmland adjacent) margins respectively. Most importantly, the crown width in 99% of the levee profiles located on the urban side was below the minimum required. The paper also points out the importance of evaluating all four geometric parameters, not just the elevation of the levee, by assessing its level of performance through a geometric assessment.