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During a flood, the geometry of a river channel constrains the flows of water and sediment, however, over many floods, bankfull channel geometry evolves to reflect the longer‐term fluxes of water and sediment supplied by the catchment. Physics‐based models predict the average relationship between bankfull geometry and discharge to within an order of magnitude, however, observed variability about the prediction remains unaccounted for. We used high‐resolution topography to extract continuous measurements of bankfull width from 67 sites spanning the continental United States, yielding a reach‐scale probabilistic description of river width for each site. Within an individual reach, bankfull river width is well‐described by a lognormal distribution. Rivers that spend a greater proportion of time above bankfull are wider for the same bankfull discharge, revealing an unrecognized pathway through which climatic or engineered changes in flow frequency could alter river geometry and therefore impact aquatic habitat and flooding risk.
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Alluvial River Width Variability
Data compilations of bankfull downstream hydraulic geometry for alluvial rivers, lidar derived high-resolution spatial series of bankfull width for 67 sites, and hydrograph metrics for sites with USGS hydrographs. This compilation is composed of three datasets: (1) a compilation of alluvial river geometry at bankfull for a variety of hydraulic attributes; (2) x, y, and z coordinates of channel bank lines for a selection of sites and their associated river widths derived from high-resolution lidar topography; and (3) statistics describing the hydrographs for a subset of the larger compilation. These data are divided into two primary sets, the larger compilation and a smaller set of sites where the bankfull width was derived from lidar topography. For the high-resolution dataset, the data are available as the coordinates of the bank lines, spatial series of distance downstream and bankfull width, and the spatial series filtered for quality.
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- Award ID(s):
- 2220505
- PAR ID:
- 10610197
- Publisher / Repository:
- HydroShare
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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