Contrôle souple de la dynamique éolienne le long d'un littoral artificialisé et propositions de gestion : le cas de la façade maritime du Grand Port Maritime de Dunkerque

Abstract : The coastline of Dunkirk seaport is a sedimentary cell where dune morphology is the result of both natural processes and human intervention. This shoreline can be divided in two parts: a western part of 7 km long, where a macrotidal beach is backed by naturally developing coastal dunes, and an eastern part consisting of a 6 km long asphalt dike overtopped in places by low elevated aeolian dunes. This study aims at (1) describing aeolian dunes and their evolution on a human-altered coast, (2) quantifying aeolian sand transport on the upper beach, the seaward slope of the foredune and the asphalt dike, and (3) suggesting management measures in order to solve windblown sand accumulation problems on harbour infrastructures. On the middle term (28 years), diachronic analysis of aerial photographs shows rapid development of dunes area since 1983. On the short term (2 years), topographic surveys reveal that dune development is still ongoing, although dune morphology keeps the marks of passed human interventions. Dunes have naturally developed on asphalt and their formation is initiated by Ammophila arenaria colonisation of numerous perpendicular cracks in the dike. A typology of these dunes is proposed. Dike toe dunes have developed at the beach/dike contact in the most eastern part of the site, where a jetty is interrupting net sediment transport. In situ field measurements revealed that aeolian sand transport is mainly controlled by wind speed and the source of sand available. Under oblique to direct onshore winds, dike toe dunes are the main source of windblown sand on the dike, and aeolian transport is enhanced by a wind speedup on the windward slope. Different kinds of windbreaks have been tested in order to solve uncontrolled aeolian sand transport problems on the dike, as well as to consolidate foredunes. It appeared from the topographic surveys carried out on the windbreaks that although their location seemed to play a major role on the amount of sand captured, fences and synthetic fabrics deployed on sandy surfaces were also able to trap windblown sand on a seaport dike. Management measures considered are a stabilisation of main sand sources at the dike toe and consolidation of foredunes with windbreaks.
Document type :
Theses
Complete list of metadatas

Cited literature [71 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00825877
Contributor : Abes Star <>
Submitted on : Wednesday, July 17, 2013 - 2:52:47 PM
Last modification on : Tuesday, July 3, 2018 - 11:34:11 AM
Long-term archiving on : Friday, October 18, 2013 - 4:31:14 AM

File

TRESCA_THESE_2013_basse_qualit...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00825877, version 2

Collections

Citation

Antoine Tresca. Contrôle souple de la dynamique éolienne le long d'un littoral artificialisé et propositions de gestion : le cas de la façade maritime du Grand Port Maritime de Dunkerque. Sciences de la Terre. Université du Littoral Côte d'Opale, 2013. Français. ⟨NNT : 2013DUNK0320⟩. ⟨tel-00825877v2⟩

Share

Metrics

Record views

1093

Files downloads

941