Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia)
The Isonzo is a 140‑km long river that draws its source in the Julian Alps in Slovenia and joins the Gulf of Trieste in the Northern Adriatic, Italy. Its catchment area (~3400 km2) consists of mid‑altitude mountains (70%), a piedmont (22%), and a coastal plain (8%) influenced by Mediterranean climat...
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| Argitaratua izan da: | URI:https://journals.openedition.org/mediterranee, |
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| Formatua: | Article ou chapitre numérique |
| Hizkuntza: | Anglais |
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Méditerranée
2015
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| Sarrera elektronikoa: | Accès Université d'Orléans et IFPM Accès Université d'Orléans et IFPM |
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openedition-oai:revues.org:mediterranee_7253 |
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| record_format |
openedition |
| collection |
OpenEdition Journal |
| language |
Anglais |
| format |
Article ou chapitre numérique |
| building |
0/Bibliothèque numérique/ 1/Bibliothèque numérique/OpenEdition Journals/ |
| topic |
Italie petit âge glaciaire métamorphose fluviale Isonzo post‑petit âge glaciaire actions anthropiques Italy Little Ice Age Isonzo River post‑Little Ice Age fluvial metamorphosis anthropogenic impacts |
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Italie petit âge glaciaire métamorphose fluviale Isonzo post‑petit âge glaciaire actions anthropiques Italy Little Ice Age Isonzo River post‑Little Ice Age fluvial metamorphosis anthropogenic impacts Siché, Isabelle Arnaud‑Fassetta, Gilles Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia) |
| description |
The Isonzo is a 140‑km long river that draws its source in the Julian Alps in Slovenia and joins the Gulf of Trieste in the Northern Adriatic, Italy. Its catchment area (~3400 km2) consists of mid‑altitude mountains (70%), a piedmont (22%), and a coastal plain (8%) influenced by Mediterranean climatic conditions. The river is a high‑energy system due to its pronounced hydraulical gradients and with frequent damage to man‑made structures. The objective of this study is to determine the recent functioning of the Isonzo River by (i) a diachronic (from the Little Ice Age), plan‑form analysis of the alluvial plain, using old maps, topographic maps of the IGM and aerial photographs, and (ii) an analysis of channel incision and sediment transport, using data derived from national and regional water services and field observations. Over the last 200 years, the Isonzo River shows a clear tendency to active‑channel narrowing between 15 km and 2 km upstream of the river‑mouth. This phenomenon was accompanied by an incision of the active channel, estimated to be between 0.5 m and 1.5 m at the most vulnerable sites. In the context of climate change since ca. 1860, the narrowing/incision of the active channel increased from the 1880s to 1920s, and prticularly since 1960, because of human impacts (channelisation, embankments, dams) in the catchment, and despite the increase of flood frequencies. The recent hydro‑morpho‑sedimentary functioning of the Isonzo shows that the river is still in a transitional phase towards a physical equilibrium that changes after every human intervention in the active channel. |
| author |
Siché, Isabelle Arnaud‑Fassetta, Gilles |
| author_facet |
Siché, Isabelle Arnaud‑Fassetta, Gilles |
| author_sort |
Siché, Isabelle |
| title |
Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia) |
| title_short |
Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia) |
| title_full |
Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia) |
| title_fullStr |
Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia) |
| title_full_unstemmed |
Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia) |
| title_sort |
anthropogenic activities since the end of the little ice age: a critical factor driving fluvial changes on the isonzo river (italy, slovenia) |
| publisher |
Méditerranée |
| publishDate |
2015 |
| container_title |
URI:https://journals.openedition.org/mediterranee |
| url |
https://ezproxy.univ-orleans.fr/login?url=https://doi.org/10.4000/mediterranee.7253 https://ezproxy.univ-orleans.fr/login?url=https://journals.openedition.org/mediterranee/7253 |
| _version_ |
1877294460710158336 |
| spelling |
openedition-oai:revues.org:mediterranee_7253 https://doi.org/10.4000/mediterranee.7253 urn:doi:10.4000/mediterranee.7253 en https://journals.openedition.org/mediterranee/7253 2015-01-22T01:00:00Z info:eu-repo/semantics/openAccess article info:eu-repo/semantics/article urn:handle:20.500.13089/i7jq All rights reserved Anthropogenic activities since the end of the Little Ice Age: a critical factor driving fluvial changes on the Isonzo River (Italy, Slovenia) Méditerranée Presses Universitaires de Provence info:eu-repo/semantics/reference/issn/1760-8538 info:eu-repo/semantics/reference/issn/0025-8296 URI:https://journals.openedition.org/mediterranee Siché, Isabelle Arnaud‑Fassetta, Gilles Italie petit âge glaciaire métamorphose fluviale Isonzo post‑petit âge glaciaire actions anthropiques Italy Little Ice Age Isonzo River post‑Little Ice Age fluvial metamorphosis anthropogenic impacts The Isonzo is a 140‑km long river that draws its source in the Julian Alps in Slovenia and joins the Gulf of Trieste in the Northern Adriatic, Italy. Its catchment area (~3400 km2) consists of mid‑altitude mountains (70%), a piedmont (22%), and a coastal plain (8%) influenced by Mediterranean climatic conditions. The river is a high‑energy system due to its pronounced hydraulical gradients and with frequent damage to man‑made structures. The objective of this study is to determine the recent functioning of the Isonzo River by (i) a diachronic (from the Little Ice Age), plan‑form analysis of the alluvial plain, using old maps, topographic maps of the IGM and aerial photographs, and (ii) an analysis of channel incision and sediment transport, using data derived from national and regional water services and field observations. Over the last 200 years, the Isonzo River shows a clear tendency to active‑channel narrowing between 15 km and 2 km upstream of the river‑mouth. This phenomenon was accompanied by an incision of the active channel, estimated to be between 0.5 m and 1.5 m at the most vulnerable sites. In the context of climate change since ca. 1860, the narrowing/incision of the active channel increased from the 1880s to 1920s, and prticularly since 1960, because of human impacts (channelisation, embankments, dams) in the catchment, and despite the increase of flood frequencies. The recent hydro‑morpho‑sedimentary functioning of the Isonzo shows that the river is still in a transitional phase towards a physical equilibrium that changes after every human intervention in the active channel. L’Isonzo est un fleuve long de 140 km qui prend sa source dans les Alpes Juliennes en Slovénie et se jette dans le golfe de Trieste en Italie, au Nord de l’Adriatique. Son bassin‑versant (~ 3 400 km2) est constitué de moyennes montagnes (70 %), d’un piedmont (22 %) et d’une plaine côtière (8 %) sous conditions climatiques méditerranéennes. Le fleuve dispose d’une forte énergie en raison de gradients hydrauliques élevés, à l’origine de dommages causés chaque année aux ouvrages d’art et aux structures hydrauliques. Cette étude a pour objectif de déterminer le fonctionnement actuel de l’Isonzo par 1) une approche diachronique de l’état de surface dans la plaine alluviale depuis le PAG, utilisant pour cela des cartes anciennes, des cartes topographiques de l’IGM et des photographies aériennes, et 2) l’analyse de l’incision du chenal couplée au transport sédimentaire, grâce aux données des services hydrauliques nationaux et régionaux et des observations de terrain. Depuis 200 ans, l’Isonzo montre une nette tendance à la contraction de sa bande active sur le tronçon situé entre 15 km et 2 km en amont de l’embouchure. Ce phénomène s’est accompagné d’une incision du chenal, estimée entre 0,5 m et 1,5 m dans les secteurs les plus touchés. Amorcé à la faveur d’une amélioration climatique depuis 1860, la contraction/incision du chenal s’est accélérée à partir des années 1880 puis des années 1920 et, surtout, depuis 1960, à cause des actions anthropiques (chenalisation, endiguement, barrages‑réservoirs) dans le bassin‑versant et ce, malgré l’augmentation de la fréquence des crues. Le bilan hydro‑morpho‑sédimentaire montre que le fleuve est encore dans un stade de transition vers un équilibre physique qui se modifie à chaque intervention humaine dans le chenal d’écoulement. |