Wavelet-Based Method for Estimating Local Dune Dimensions: Method Development and Initial Validation for Select Sand-Bed River Datasets

Quantification of local dune dimensions from bathymetric data obtained in large sand-bed rivers is important for navigation assessments and hydraulic roughness estimation. This study developed, calibrated, and tested a method for wavelet-based quantification of local dune dimensions (i.e., length and height) from linear bed elevation profiles (BEPs). The method uses the continuous wavelet transform (CWT) and leverages strengths of both the energy-normalized and amplitude-normalized CWT definitions. The method was calibrated using synthetic BEPs that mimic data obtained on the Missouri River to obtain median values and 95% confidence intervals for the method’s dune length and height estimation coefficients. Analysis of results for synthetic BEP data suggests that the wavelet-based method provides locally averaged dune dimensions. When using median coefficient values, root-mean-square errors (RMSEs) for predictions were less than 32% of mean values for the synthetic data. The method was validated by comparisons with reference dune dimension data for the Missouri and Paraná Rivers, for which the RMSE prediction errors were less than 59% and 27% of the mean values, respectively.