Sources of bias errors in flume experiments on suspended-sediment transport

Abstract

Extensive research efforts in the last few decades have only partially elucidated the complexities of suspended-sediment transport. Lacking an adequate formulation and quantification of the interaction between suspended particles and the carrier liquid, it is common practice to combine sediment mechanics theory and empiricism to obtain predictive formulations. Flume data for suspended sediment transport, however, is incomplete and often inconsistent with respect to insights into sediment effects on water flow. Improvement of the data quality/reliability for future similar studies requires identification and evaluation of the sources of bias errors that might affect the experimental results.

The present paper identifies and partially evaluates significant sources of bias errors in Hume investigations of suspended-sediment transport. Bias errors are discussed in the order in which they typically arise in the conduct of flume experiments. The paper considers first conceptual errors associated with the governing equations used for the design and interpretation of the experimental results. Considered next are bias errors generated during data acquisition and data reduction. As an outcome of bias error discussion, the paper recommends guidelines to avoid and reduce such errors, hence, to increase the reliability of the experimental results. Special emphasis is placed on illustrating the potential of the non-intrusive measurement instruments for removing bias errors.