Quantifying Hydraulic Roughness From Field Data: Can Dune Morphology Tell the Whole Story?

Hydraulic roughness is a fundamental property in river research, as it directly affects water levels, flow strength and the associated sediment transport rates. However, quantification of roughness is challenging, as it is not directly measurable in the field. In lowland rivers, bedforms are a major...

Full description

Saved in:
Bibliographic Details
Published in:Water resources research 2021-12, Vol.57 (12), p.n/a
Main Authors: Lange, S. I., Naqshband, S., Hoitink, A. J. F.
Format: Article
Language:English
Subjects:
Angles (geometry)
Bed forms
Bedforms
Depth
Dimensions
Divergence
Dunes
Elevation
Energy dissipation
Energy loss
field data
Flood predictions
Flooding
Flow control
Flow resistance
Flow separation
Friction factor
Hydraulic roughness
Hydraulics
Mathematical analysis
Oscillations
Parameterization
River banks
River beds
river dunes
River flow
Riverbeds
Rivers
Roughness
Sediment transport
Sedimentary structures
Shape effects
Statistical methods
Surveying
Topography
Trends
Variance
Variation
Water levels
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Hydraulic roughness is a fundamental property in river research, as it directly affects water levels, flow strength and the associated sediment transport rates. However, quantification of roughness is challenging, as it is not directly measurable in the field. In lowland rivers, bedforms are a major source of hydraulic roughness. Decades of research have focused on dunes to allow parameterization of roughness, with relatively little focus on field verification. This study aims to establish the predictive capacity of current roughness predictors, and to identify reasons for the unexplained part of the variance in roughness. We quantified hydraulic roughness based on the Darcy‐Weisbach friction factor (f) calculated from hydraulic field data of a 78 km‐long trajectory of the river Rhine and river Waal in the Netherlands. This is compared to predicted roughness values based on dune geometry, and to the spatial trends in the local topographic leeside angle, both inferred from bathymetric field data. Results from both approaches show the same general trend and magnitude of roughness values (0.019 
ISSN:0043-1397
1944-7973
DOI:10.1029/2021WR030329