Removing Systemic Bias in Bed-Load Transport Measurements in Large Sand-Bed Rivers

Abstract

Bed-load sediment transport is important yet difficult to measure in large, sand-bed rivers. Prior work established in theory and validated in a flume study a method known as integrated section surface difference over time version 2 (ISSDOTv2), which computes bed-load transport using sequential three dimensional (3D) bathymetric profiles. The same work identified a source of systemic error leading to an underprediction of computed transport rates. This paper demonstrates how the systemic error can be removed from ISSDOTv2 calculations to produce a more accurate dune transport value. This is demonstrated by analytic and geometric examples, and with field data from the Missouri River at Kansas City. The results of these analyses indicate that field data do exhibit the systematic error and that it is possible to extrapolate a corrected dune bed-load transport rate from field data obtained at different measurement intervals. Additionally, error bounds on this corrected value can be set. Independent validation of the resulting transport rate was not attempted due to the unreliability of physical measurements for bed-load transport in large sand-bed rivers.