An Application of Time Lapse ERT Monitoring on a River Levee During Flood Events

For the purpose of realizing the system of monitoring levee inside during flood events, we conducted a research study of the workflow for levee screening to narrow the vulnerable interval in aspect of seepage and the ERT monitoring survey result at narrowed interval. For levee screening, we conducted reviewing existing material about histories of seepage damage, safety check result for seepage and so on. Thereafter we conducted geophysical methods that effectively cover long distance. After screening we set the locations for ERT monitoring and water level observation wells as the objective interval for the detail research. On the ERT monitoring, we were able to acquire continuous measurement data during actual flood events of high river water level in which water table was generated in the levee body. We considered that ERT monitoring captured the change of resistivity change considered to be caused by ground water level variation which is related to river water level variation.