| Titre | L'enfoncement du lit de la Loire / The entrenchment of the Loire's river bed | |
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| Auteur | Zbigniew Gasowski | |
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Revue |
Géocarrefour Titre à cette date : Revue de géographie de Lyon |
| Numéro | volume 69, no 1, 1994 Enfoncement des lits fluviaux : processus naturels et impacts des activités humaines | |
| Page | 41-45 | |
| Résumé anglais |
Sand and gravel harvesting, which peaked in 1979, are responsible for major problems in the Loire valley. The region of Centre alone provides 6.4 MT while the computed transit of alluvial sediments averages only 0.5 - 0.7 MT, i.e. 1 MT per year. The water level dropped and the degradation of the bed (up to 3 m) induced serious ecological damage and threatened engineering works such as that Tours bridge which collapsed in 1978. Moreover, the comparison of water profiles since 1864 reveals that floods reach higher levels due to the aggradation of islands and banks. However, gravel harvesting is not the only cause of bed degradation: river rectification works of the XlXth century which increased stream power and reservoirs which control load transit play a significant role. Gravel harvesting ceased in the river bed in 1992 except in some minor places. Extraction is now located in the floodplain and on the edge of the valley. Source : Éditeur (via Persée) |
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| Article en ligne | http://www.persee.fr/web/revues/home/prescript/article/geoca_0035-113x_1994_num_69_1_4236 |
