Relationship between Bathymetric Accuracy and Lake Bottom Topography in Reservoir Bathymetric Survey Using Acoustic Bathymetry

Abstract

Sediment volume surveying is mandatory for many dam reservoirs and is an essential source of information for safe and sustainable dam operation. In recent years, the emergence of multibeam echo sounders (MBES) has made it possible to survey bathymetry with much higher accuracy than in the past. On the other hand, errors are inevitable in bathymetric surveying, which sometimes manifests as a problem of “negative sedimentation,” a decrease in the amount of sediment in the data compared to the previous period. This study introduces the factors that cause errors in acoustic bathymetry, including MBES. In addition, we analyze 20 years of acoustic bathymetry data obtained at the Murou Dam, Japan, and show that errors frequently occur in the reservoir-sloped areas.