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Analytical model of sand spit evolution

Palalane, Jaime LU ; Larson, Magnus LU and Hanson, Hans LU (2014) 34th International Conference on Coastal Engineering In Proceedings of the Coastal Engineering Conference 2014-January.
Abstract
Spits typically consist of sand or gravel and are commonly occurring morphological features at inlets, river mouths, and the down-drift ends of barrier islands. Thus, they may form at the ocean-, lake-, or bay-side of inlets, entrances, and river mouths. Apart from the scientific interest in spits and their evolution, engineers have often studied spits with regard to their penetration into river mouths or inlets, restricting the flow rate and possibly even causing closure of the inlet (river mouth). Governing processes for spit growth under a predominant longshore transport, causing down-drift accumulation of sand, were reviewed. Based on this review, equations for the simulation of spit growth from former studies were improved, and their... (More)
Spits typically consist of sand or gravel and are commonly occurring morphological features at inlets, river mouths, and the down-drift ends of barrier islands. Thus, they may form at the ocean-, lake-, or bay-side of inlets, entrances, and river mouths. Apart from the scientific interest in spits and their evolution, engineers have often studied spits with regard to their penetration into river mouths or inlets, restricting the flow rate and possibly even causing closure of the inlet (river mouth). Governing processes for spit growth under a predominant longshore transport, causing down-drift accumulation of sand, were reviewed. Based on this review, equations for the simulation of spit growth from former studies were improved, and their analytical solutions employed to build a model able to reproduce linear spit elongation. Major modifications were introduced in the equations to account for variation in spit cross-section with time, and to better describe the increase in active profile height and transport at the down-drift end of the spit as it elongates through the inlet channel. The analytical solutions were compared with data from the laboratory and field case studies. The case studies represent situations of unrestricted and restricted growth, including time-varying cross-sectional spit area and increasing active profile height. Results showed that the generalized expression for time-varying spit cross-sectional area enabled the adoption of a more realistic trapezoidal cross-section for the modeled spits. The model also contributed to estimate the net longshore sediment transport rates, facilitating comparison with observations from the different case studies. For unrestricted spit growth, it was possible to give a satisfactory representation of spit elongation over the analyzed periods, although for some study areas a single elongation rate could not accurately predict increasing spit lengths over long periods of analysis, i.e., above 50 years. Nevertheless, the model has a high potential to make rapid quantitative predictions, being a useful and valid tool for initial estimates in engineering projects. (Less)
Please use this url to cite or link to this publication:
author
; and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Analytical model, Longshore transport, Spit
host publication
Proceedings of 34th Conference on Coastal Engineering, Seoul, Korea, 2014
series title
Proceedings of the Coastal Engineering Conference
editor
Lynett, Patrick J.
volume
2014-January
publisher
Coastal Engineering Research Council
conference name
34th International Conference on Coastal Engineering
conference location
Seoul, Korea, Republic of
conference dates
2014-06-15 - 2014-06-20
external identifiers
  • scopus:84957612310
ISSN
0161-3782
ISBN
978-0-9896611-2-6
DOI
10.9753/icce.v34.sediment.72
language
English
LU publication?
yes
id
71ff1c26-1027-4a17-bc92-771cb24b0fcc
date added to LUP
2019-01-30 15:10:07
date last changed
2021-07-13 01:34:38
@inproceedings{71ff1c26-1027-4a17-bc92-771cb24b0fcc,
  abstract     = {Spits typically consist of sand or gravel and are commonly occurring morphological features at inlets, river mouths, and the down-drift ends of barrier islands. Thus, they may form at the ocean-, lake-, or bay-side of inlets, entrances, and river mouths. Apart from the scientific interest in spits and their evolution, engineers have often studied spits with regard to their penetration into river mouths or inlets, restricting the flow rate and possibly even causing closure of the inlet (river mouth). Governing processes for spit growth under a predominant longshore transport, causing down-drift accumulation of sand, were reviewed. Based on this review, equations for the simulation of spit growth from former studies were improved, and their analytical solutions employed to build a model able to reproduce linear spit elongation. Major modifications were introduced in the equations to account for variation in spit cross-section with time, and to better describe the increase in active profile height and transport at the down-drift end of the spit as it elongates through the inlet channel. The analytical solutions were compared with data from the laboratory and field case studies. The case studies represent situations of unrestricted and restricted growth, including time-varying cross-sectional spit area and increasing active profile height. Results showed that the generalized expression for time-varying spit cross-sectional area enabled the adoption of a more realistic trapezoidal cross-section for the modeled spits. The model also contributed to estimate the net longshore sediment transport rates, facilitating comparison with observations from the different case studies. For unrestricted spit growth, it was possible to give a satisfactory representation of spit elongation over the analyzed periods, although for some study areas a single elongation rate could not accurately predict increasing spit lengths over long periods of analysis, i.e., above 50 years. Nevertheless, the model has a high potential to make rapid quantitative predictions, being a useful and valid tool for initial estimates in engineering projects.},
  author       = {Palalane, Jaime and Larson, Magnus and Hanson, Hans},
  booktitle    = {Proceedings of 34th Conference on Coastal Engineering, Seoul, Korea, 2014},
  editor       = {Lynett, Patrick J.},
  isbn         = {978-0-9896611-2-6},
  issn         = {0161-3782},
  language     = {eng},
  month        = {01},
  publisher    = {Coastal Engineering Research Council},
  series       = {Proceedings of the Coastal Engineering Conference},
  title        = {Analytical model of sand spit evolution},
  url          = {http://dx.doi.org/10.9753/icce.v34.sediment.72},
  doi          = {10.9753/icce.v34.sediment.72},
  volume       = {2014-January},
  year         = {2014},
}