The University of Southampton
University of Southampton Institutional Repository

Spontaneous formation and degradation of pool-riffle morphology and sediment sorting using a simple fractional transport model

Spontaneous formation and degradation of pool-riffle morphology and sediment sorting using a simple fractional transport model
Spontaneous formation and degradation of pool-riffle morphology and sediment sorting using a simple fractional transport model
Many gravel bed streams have a typical bed morphology consisting of pool-riffle sequences, which provides important habitat diversity both in terms of flow and substrate. A complete explanation of pool-riffle genesis and self-maintenance remains elusive and, despite advances in understanding the effects of flow spatial and temporal variability, the key sediment processes have been only marginally explored. Here we use a 1D unsteady multi-fraction morphodynamic model to explain the formation and degradation of pool-riffle sequences. Using a 1-year time series of measured flows below bankfull on a stream in which we have removed initial bedforms and sediment sorting our model spontaneously generates pools with finer substrate at narrow sections and riffles with coarser sediment at wider sections, closely resembling the natural bed morphology. Additional experiments show that under our modelling assumptions a variable flow regime is fundamental for development and self-maintenance of the longitudinal grain sorting characteristic of pool-riffle sequences, which could not be obtained or maintained with discharges held constant over relatively long periods.
habitat, model, morphology, pool-riffle, sediment, sorting
0094-8276
L06407-[7pp]
de Almeida, Gustavo A. M.
f6edffc1-7bb3-443f-8829-e471b6514a7e
Rodriguez, Jose F.
7d2ce7e6-c404-45da-9a89-5ced480e2039
de Almeida, Gustavo A. M.
f6edffc1-7bb3-443f-8829-e471b6514a7e
Rodriguez, Jose F.
7d2ce7e6-c404-45da-9a89-5ced480e2039

de Almeida, Gustavo A. M. and Rodriguez, Jose F. (2012) Spontaneous formation and degradation of pool-riffle morphology and sediment sorting using a simple fractional transport model. Geophysical Research Letters, 39 (6), L06407-[7pp]. (doi:10.1029/2012GL051059).

Record type: Article

Abstract

Many gravel bed streams have a typical bed morphology consisting of pool-riffle sequences, which provides important habitat diversity both in terms of flow and substrate. A complete explanation of pool-riffle genesis and self-maintenance remains elusive and, despite advances in understanding the effects of flow spatial and temporal variability, the key sediment processes have been only marginally explored. Here we use a 1D unsteady multi-fraction morphodynamic model to explain the formation and degradation of pool-riffle sequences. Using a 1-year time series of measured flows below bankfull on a stream in which we have removed initial bedforms and sediment sorting our model spontaneously generates pools with finer substrate at narrow sections and riffles with coarser sediment at wider sections, closely resembling the natural bed morphology. Additional experiments show that under our modelling assumptions a variable flow regime is fundamental for development and self-maintenance of the longitudinal grain sorting characteristic of pool-riffle sequences, which could not be obtained or maintained with discharges held constant over relatively long periods.

Text
GRL_2012.pdf - Accepted Manuscript
Download (633kB)

More information

Published date: March 2012
Keywords: habitat, model, morphology, pool-riffle, sediment, sorting
Organisations: Water & Environmental Engineering Group

Identifiers

Local EPrints ID: 356384
URI: https://eprints.soton.ac.uk/id/eprint/356384
ISSN: 0094-8276
PURE UUID: c7cdaef0-629e-4629-8d8b-6902a7ef73a2
ORCID for Gustavo A. M. de Almeida: ORCID iD orcid.org/0000-0002-3291-3985

Catalogue record

Date deposited: 10 Sep 2013 13:16
Last modified: 20 Jul 2019 00:37

Export record

Altmetrics

Contributors

Author: Jose F. Rodriguez

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×