{"id":667,"date":"2013-09-26T13:38:35","date_gmt":"2013-09-26T11:38:35","guid":{"rendered":"http:\/\/wp.unil.ch\/risk\/?p=667"},"modified":"2013-09-26T14:00:27","modified_gmt":"2013-09-26T12:00:27","slug":"sebastien-levy-analyse-de-levolution-morphologique-dune-partie-du-bassin-versant-de-la-riviere-chacoura-quebec-canada","status":"publish","type":"post","link":"https:\/\/wp.unil.ch\/risk\/sebastien-levy-analyse-de-levolution-morphologique-dune-partie-du-bassin-versant-de-la-riviere-chacoura-quebec-canada\/","title":{"rendered":"S\u00e9bastien L\u00e9vy: Analyse de l\u2019\u00e9volution morphologique d\u2019une partie du bassin versant de la rivi\u00e8re Chacoura, Qu\u00e9bec, Canada."},"content":{"rendered":"

S\u00e9bastien L\u00e9vy<\/em>
\nCo-supervisors: Prof. Michel Jaboyedoff,\u00a0Professeur Jacques Locat<\/em>
\nExpert:\u00a0Alexandre Loye<\/em><\/p>\n

The large plains of Eastern Canada sensitive clays are cut by many rivers, in a way\u00a0that their slopes have been and are still affected by landslides. They play a major role in the\u00a0modelling of the landscape of these regions, in addition to induct a risk for human\u00a0infrastructures. The role of erosion as a trigger of landslides is also important.<\/p>\n

On the Chacoura River, north of Louiseville (Quebec), several large scars of\u00a0landslides, more or less recent, are visible. A first inventory of landslides and areas of erosion\u00a0was carried out in 1984 on some series of aerial photographs, covering a period from 1948 to\u00a01979. It suggests that the majority of recorded landslides are located in areas that were\u00a0previously affected by erosion. In this Master Thesis, a detailed analysis of aerial\u00a0photographs, dating from 1948 to 1997 and a LiDAR-Digital Elevation Model (DEM) dating\u00a0from 2007, has been done, using four different approaches: (1) a map of the phenomena on a\u00a0portion of the river, which is considered as very active, was drawn by identifying various\u00a0elements such as landslides, limits of the slope, position of the river, area covered by the\u00a0forest and agricultural drainage structures. (2) A quantitative analysis based on the previous\u00a0map has shown the temporal evolution of landslides in terms of area and volume, using\u00a0statistical relationships. (3) The study focused on two flows, which happened in 1976 and\u00a01990; it consisted of a detailed analysis of the evolution of their perimeter, area and the initial\u00a0conditions of the slope. The comparison of DEMs was used to estimate volumes eroded in\u00a0these flows, and in the entire zone of interest. (4) The last part focused on the general\u00a0evolution of the river valley, and particularly the identification of areas where erosion could\u00a0be more active in the future. This study was based on transverse and longitudinal profiles, and\u00a0using the Sloping Local Base Level (SLBL) method.<\/p>\n

The results show that the location of landslides is firmly linked to the presence of\u00a0typical specific topographic features, such as (1) the shape of the meandering river, (2) the\u00a0flow of agricultural drainage, or (3) the erosion at the toe of the slope. The study of landslides\u00a0over a period of 59 years shows also that (4) the major landslide scars in this region are in fact\u00a0the sum of several events of lesser importance. The analysis of the development of Chacoura\u00a0River valley indicates that (5) it is still at an early stage of development. Besides (6) the lower\u00a0part of the river seems to be relatively stable, however the upper part and the tributaries will\u00a0probably face significant changes in the next 10,000 years. Finally hazard maps, based on the\u00a0measured distances of flow retrogression have been created for the St-L\u00e9on-le-Grand region.<\/p>\n","protected":false},"excerpt":{"rendered":"

S\u00e9bastien L\u00e9vy Co-supervisors: Prof. Michel Jaboyedoff,\u00a0Professeur Jacques Locat Expert:\u00a0Alexandre Loye The large plains of Eastern Canada sensitive clays are cut by many rivers, in a way\u00a0that their slopes have been … <\/p>\n","protected":false},"author":1341,"featured_media":883,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","ngg_post_thumbnail":0,"footnotes":""},"categories":[73758],"tags":[51880],"class_list":{"0":"post-667","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-masters_completed","8":"tag-51880"},"_links":{"self":[{"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/posts\/667","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/users\/1341"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/comments?post=667"}],"version-history":[{"count":0,"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/posts\/667\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/media\/883"}],"wp:attachment":[{"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/media?parent=667"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/categories?post=667"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.unil.ch\/risk\/wp-json\/wp\/v2\/tags?post=667"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}