{"id":183,"date":"2018-05-03T20:56:35","date_gmt":"2018-05-03T18:56:35","guid":{"rendered":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/?page_id=183"},"modified":"2020-01-28T10:03:53","modified_gmt":"2020-01-28T09:03:53","slug":"retenue-collinaire-de-bajamont","status":"publish","type":"page","link":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/retenue-collinaire-de-bajamont\/","title":{"rendered":"47 &#8211; Retenue collinaire de Bajamont"},"content":{"rendered":"\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"50\" height=\"58\" src=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2019\/10\/Logo-EDD-e1579619428654.png\" alt=\"\" class=\"wp-image-1338\" \/><\/figure>\n\n\n<table style=\"height: 60px\" width=\"100%\">\n<tbody>\n<tr>\n<td style=\"text-align: center\" colspan=\"2\" width=\"412\"><span style=\"color: #00ccff\"><a style=\"color: #00ccff\" href=\"http:\/\/u.osmfr.org\/m\/227985\/\"><strong>Coordonn\u00e9es GPS du parking<\/strong><\/a><\/span><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\" width=\"206\"><span style=\"color: #000000\">44.263861<\/span><\/td>\n<td style=\"text-align: center\" width=\"206\"><span style=\"color: #000000\">0.710378<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span style=\"color: #000000\"><strong><u>Description du site<\/u> :<\/strong><\/span><\/p>\n<ul>\n<li><span style=\"color: #000000\"><strong>Historique<\/strong><\/span><\/li>\n<\/ul>\n<p><span style=\"color: #000000\">Construite entre 1997 et 1998 suite aux <strong>inondations<\/strong> ayant touch\u00e9 Pont-du-Casse en 1993, cette retenue d\u2019une superficie de 24ha poss\u00e8de une capacit\u00e9 de stockage de 1.172.000m<sup>3<\/sup> (un volume \u00e9quivalant \u00e0 celui de 312 piscines olympiques) dont un peu plus de 25% (300.000m<sup>3<\/sup>) r\u00e9serv\u00e9s \u00e0 l\u2019\u00e9cr\u00eatement, le reste permettant de soutenir les \u00e9tiages, d\u2019irriguer et de participer au tourisme vert (marche, p\u00eache\u2026). Situ\u00e9e sur le cours du ruisseau de Laroque, affluant de la Masse ayant inond\u00e9e Pont-du-Casse en 1993, cette retenue voit s\u2019\u00e9couler l\u2019eau collect\u00e9e sur un bassin versant de 880ha.<\/span><\/p>\n<figure id=\"attachment_185\" aria-describedby=\"caption-attachment-185\" style=\"width: 1089px\" class=\"wp-caption alignleft\"><a style=\"color: #000000\" href=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Retenue.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-185\" src=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Retenue.png\" alt=\"\" width=\"1089\" height=\"300\" srcset=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Retenue.png 1089w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Retenue-300x83.png 300w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Retenue-768x212.png 768w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Retenue-1024x282.png 1024w\" sizes=\"auto, (max-width: 1089px) 100vw, 1089px\" \/><\/a><figcaption id=\"caption-attachment-185\" class=\"wp-caption-text\"><span style=\"color: #000000\">Vue de la retenue collinaire depuis l\u2019aire de stationnement (\u00e0 l\u2019extr\u00e9mit\u00e9 nord du barrage)<\/span><\/figcaption><\/figure>\n<ul>\n<li><span style=\"color: #000000\"><strong>Fonctionnement<\/strong><\/span><\/li>\n<\/ul>\n<p><span style=\"color: #000000\">C\u2019est en retenant les eaux lors d\u2019une crue et en les restituant progressivement, via le pertuis, apr\u00e8s cet \u00e9pisode que ce bassin assure sa fonction d\u2019\u00e9cr\u00eatement. On consid\u00e8re que cet ouvrage permet ainsi de r\u00e9duire de 90% le d\u00e9bit de pointe d\u2019une crue centennale, r\u00e9duisant ainsi l\u2019al\u00e9a et donc le risque d\u2019inondation en aval. On note qu\u2019un bassin assurant la seule fonction d\u2019\u00e9cr\u00eatement est destin\u00e9 \u00e0 rester sec la majeure partie du temps alors que la retenue collinaire de Bajamont n\u2019est jamais ass\u00e9ch\u00e9e du fait des diff\u00e9rentes fonctions pour lesquelles elle a \u00e9t\u00e9 am\u00e9nag\u00e9e. Cette retenue est d\u2019ailleurs \u00e9quip\u00e9e d\u2019un syst\u00e8me de t\u00e9l\u00e9transmission permettant une surveillance \u00e0 distance de la hauteur du niveau de l\u2019eau ainsi qu\u2019une programmation de la fermeture\/ouverture des vannes situ\u00e9es sur la conduite reli\u00e9e au pertuis. Lorsque la capacit\u00e9 de stockage est atteinte, l\u2019exc\u00e9dent d\u2019eau parvenant dans la retenue peut rejoindre le ruisseau via un d\u00e9versoir situ\u00e9 au sud du barrage.<\/span><\/p>\n<figure id=\"attachment_186\" aria-describedby=\"caption-attachment-186\" style=\"width: 1089px\" class=\"wp-caption alignleft\"><a style=\"color: #000000\" href=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-186\" src=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis.png\" alt=\"\" width=\"1089\" height=\"372\" srcset=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis.png 1089w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis-300x102.png 300w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis-768x262.png 768w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis-1024x350.png 1024w\" sizes=\"auto, (max-width: 1089px) 100vw, 1089px\" \/><\/a><figcaption id=\"caption-attachment-186\" class=\"wp-caption-text\"><span style=\"color: #000000\">Pertuis et point de convergence de l\u2019eau provenant du pertuis et du d\u00e9versoir accessible depuis la route passant au bas du barrage<\/span><\/figcaption><\/figure>\n<figure id=\"attachment_187\" aria-describedby=\"caption-attachment-187\" style=\"width: 558px\" class=\"wp-caption alignleft\"><a style=\"color: #000000\" href=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis-ouvert.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-187\" src=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis-ouvert.png\" alt=\"\" width=\"558\" height=\"839\" srcset=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis-ouvert.png 558w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Pertuis-ouvert-200x300.png 200w\" sizes=\"auto, (max-width: 558px) 100vw, 558px\" \/><\/a><figcaption id=\"caption-attachment-187\" class=\"wp-caption-text\"><span style=\"color: #000000\">D\u00e9tail du pertuis ouvert<\/span><\/figcaption><\/figure>\n<p>\u00a0<\/p>\n<figure id=\"attachment_188\" aria-describedby=\"caption-attachment-188\" style=\"width: 939px\" class=\"wp-caption alignleft\"><a style=\"color: #000000\" href=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/D\u00e9versoir.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-188\" src=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/D\u00e9versoir.png\" alt=\"\" width=\"939\" height=\"416\" \/><\/a><figcaption id=\"caption-attachment-188\" class=\"wp-caption-text\"><span style=\"color: #000000\">D\u00e9versoir (\u00e0 l\u2019extr\u00e9mit\u00e9 sud du barrage)<\/span><\/figcaption><\/figure>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p><span style=\"color: #000000\"><strong><u>Activit\u00e9s envisageables<\/u> :<\/strong><\/span><\/p>\n<ul>\n<li><span style=\"color: #000000\">R\u00e9aliser un sch\u00e9ma fonctionnel de la retenue collinaire.<\/span><\/li>\n<li><span style=\"color: #000000\">En compl\u00e9ment, une activit\u00e9 utilisant les TICE, mesurer la superficie de la retenue (G\u00e9oportail, GoogleEarth) et estimer sa capacit\u00e9 de stockage.<\/span><\/li>\n<\/ul>\n<p><span style=\"color: #000000\"><strong><u>Acc\u00e8s \/ s\u00e9curit\u00e9<\/u>\u00a0:<\/strong><\/span><\/p>\n<p><span style=\"color: #000000\">Possibilit\u00e9 de stationnement au nord du barrage, sur le parking situ\u00e9 le long de la D310, ou tout de suite apr\u00e8s \u00eatre pass\u00e9 sous le viaduc ferroviaire (\u00e0 la sortie de Bajamont, en direction de Laroque-Timbault), devant le cimeti\u00e8re.<\/span><\/p>\n<figure id=\"attachment_184\" aria-describedby=\"caption-attachment-184\" style=\"width: 1083px\" class=\"wp-caption alignleft\"><a style=\"color: #000000\" href=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Bajamont.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-184\" src=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Bajamont.png\" alt=\"\" width=\"1083\" height=\"541\" srcset=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Bajamont.png 1083w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Bajamont-300x150.png 300w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Bajamont-768x384.png 768w, https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-content\/uploads\/sites\/59\/2018\/05\/Bajamont-1024x512.png 1024w\" sizes=\"auto, (max-width: 1083px) 100vw, 1083px\" \/><\/a><figcaption id=\"caption-attachment-184\" class=\"wp-caption-text\"><span style=\"color: #000000\">Acc\u00e8s<\/span><\/figcaption><\/figure>\n<p><span style=\"color: #000000\"><u style=\"font-weight: bold\">Mots-cl\u00e9s et liens avec les programmes<\/u>\u00a0:<\/span><\/p>\n<p><span style=\"color: #000000\">Al\u00e9as, protection, risque naturel (inondation), m\u00e9t\u00e9orologie (dynamique des masses d\u2019eau)<\/span><\/p>\n<table style=\"height: 405px\" width=\"1120\">\n<tbody>\n<tr>\n<td colspan=\"2\" width=\"321\">\n<p style=\"text-align: center\"><span style=\"color: #000000\"><strong>Coll\u00e8ge<\/strong><\/span><\/p>\n<\/td>\n<td width=\"321\">\n<p style=\"text-align: center\"><span style=\"color: #000000\"><strong>Lyc\u00e9e<\/strong><\/span><\/p>\n<\/td>\n<\/tr>\n<tr>\n<td width=\"58\"><span style=\"color: #000000\">Cycle 3<\/span><\/td>\n<td width=\"264\"><span style=\"color: #000000\">Relier certains ph\u00e9nom\u00e8nes naturels (temp\u00eates, inondations, tremblements de terre) \u00e0 des risques pour les populations.<\/span>\n<p>\u00a0<\/p>\n<p><span style=\"color: #000000\">Ph\u00e9nom\u00e8nes g\u00e9ologiques traduisant activit\u00e9 interne de la terre (volcanisme, tremblements de terre&#8230;).<\/span><\/p>\n<p><span style=\"color: #000000\">Ph\u00e9nom\u00e8nes traduisant l\u2019activit\u00e9 externe de la Terre : ph\u00e9nom\u00e8nes m\u00e9t\u00e9orologiques et climatiques ; \u00e9v\u00e8nements extr\u00eames (temp\u00eates, cyclones, inondations et s\u00e8cheresses&#8230;).<\/span><\/p>\n<\/td>\n<td width=\"321\"><span style=\"color: #000000\">\u00a0<\/span><\/td>\n<\/tr>\n<tr>\n<td width=\"58\"><span style=\"color: #000000\">Cycle 4<\/span><\/td>\n<td width=\"264\"><span style=\"color: #000000\">Les ph\u00e9nom\u00e8nes naturels : risques et enjeux pour l\u2019\u00eatre humain<\/span>\n<p>\u00a0<\/p>\n<p><span style=\"color: #000000\">Notions d\u2019al\u00e9as, de vuln\u00e9rabilit\u00e9 et de risque en lien avec les ph\u00e9nom\u00e8nes naturels ; pr\u00e9visions<\/span><\/p>\n<\/td>\n<td width=\"321\"><span style=\"color: #000000\">\u00a0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span style=\"color: #000000\"><strong><u>Transversalit\u00e9<\/u> :<\/strong><\/span><\/p>\n<p><span style=\"color: #000000\">Cycle 4 G\u00e9ographie\u00a0: Pr\u00e9venir les risques, s\u2019adapter au changement global<\/span><\/p>\n<p style=\"padding-left: 30px\"><span style=\"color: #000000\">\u00bb\u00a0 Le changement global et ses principaux effets g\u00e9ographiques r\u00e9gionaux.<\/span><\/p>\n<p><span style=\"color: #000000\"><u style=\"font-weight: bold\">Capacit\u00e9s et attitudes<\/u> :<\/span><\/p>\n<p><span style=\"color: #000000\">C2 &#8211; Communiquer en utilisant une expression graphique (croquis, sch\u00e9mas, graphique, tableau)<\/span><\/p>\n<p><span style=\"color: #000000\">D3 &#8211; Percevoir le lien entre sciences et techniques<\/span><\/p>\n<p><span style=\"color: #000000\">D4 &#8211; Montrer de l\u2019int\u00e9r\u00eat pour les progr\u00e8s scientifiques et techniques<\/span><\/p>\n<p><span style=\"color: #000000\">E2 &#8211; Manifester de l\u2019int\u00e9r\u00eat pour la vie publique et les grands enjeux de la soci\u00e9t\u00e9<\/span><\/p>\n<p><span style=\"color: #000000\">E3 &#8211; \u00catre conscient de sa responsabilit\u00e9 face \u00e0 l\u2019environnement, la sant\u00e9, le monde vivant<\/span><\/p>\n<p><span style=\"color: #339966\"><strong><span style=\"text-decoration: underline\">Ressource pour l&#8217;EDD<\/span> :<\/strong><\/span><\/p>\n<p style=\"font-weight: 400\"><span style=\"color: #339966\">L\u2019\u00e9tude de ce site permet d\u2019observer les cons\u00e9quences directes des retenues collinaires sur les \u00e9coulements naturels de l\u2019eau et peut \u00e9ventuellement permettre une comparaison des caract\u00e9ristiques physico-chimiques (comme la temp\u00e9rature) dans le cours d\u2019eau alimentant la retenue \u00a0et dans l\u2019eau lib\u00e9r\u00e9e \u00e0 l\u2019exutoire. Une r\u00e9flexion peut alors \u00eatre engag\u00e9e sur les cons\u00e9quences locales (hydrologiques, physico-chimiques, biologiques\u2026) et globales (modification du cycle de l\u2019eau\u2026) de ce genre d\u2019am\u00e9nagements destin\u00e9s \u00e0 r\u00e9duire l\u2019al\u00e9a en aval et \u00e0 satisfaire les besoins agricoles en eau en p\u00e9riode estivale. Il est ainsi possible de soulever les paradoxes que leur installation g\u00e9n\u00e8re\u00a0: soutenir l\u2019irrigation pour faire face au r\u00e9chauffement climatique \/ modification du cycle de l\u2019eau et accroissement du d\u00e9r\u00e8glement climatique\u00a0; constituer une r\u00e9serve piscicole \/ affecter la faune en aval par les modifications physico-chimiques du milieu (pH\u00a0, oxyg\u00e9nation, concentration en nitrates\u2026). Ce genre d\u2019\u00e9tude permet en outre de comprendre les tenants et les aboutissants de l\u2019am\u00e9nagement ill\u00e9gal de la retenue d\u2019eau collective de Caussade.<\/span><\/p>\n<p style=\"font-weight: 400\"><span style=\"color: #339966\">Synth\u00e8se des connaissances et des donn\u00e9es existantes sur les retenues collinaires (les diff\u00e9rents impacts sont pr\u00e9sent\u00e9s) :<\/span>\u00a0<a href=\"http:\/\/doc-oai.eaurmc.fr\/cindocoai\/download\/5328\/1\/synthese%20retenues%20coll.pdf_2839Ko\" data-saferedirecturl=\"https:\/\/www.google.com\/url?q=http:\/\/doc-oai.eaurmc.fr\/cindocoai\/download\/5328\/1\/synthese%2520retenues%2520coll.pdf_2839Ko&amp;source=gmail&amp;ust=1580229661375000&amp;usg=AFQjCNFDbISNkjPnooZsRs6bNQ13Y95lCw\">http:\/\/doc-oai.eaurmc.fr\/cindocoai\/download\/5328\/1\/synthese%20retenues%20coll.pdf_2839Ko<\/a><\/p>\n<p style=\"font-weight: 400\"><span style=\"color: #339966\">Question d\u2019actualit\u00e9 au gouvernement au sujet du lac de Caussade\u00a0:<\/span>\u00a0<a href=\"https:\/\/www.senat.fr\/questions\/base\/2019\/qSEQ19010614G.html\" data-saferedirecturl=\"https:\/\/www.google.com\/url?q=https:\/\/www.senat.fr\/questions\/base\/2019\/qSEQ19010614G.html&amp;source=gmail&amp;ust=1580229661375000&amp;usg=AFQjCNH6GqHvV9U9gRWb_goCVnmdEYuuXA\">https:\/\/www.senat.fr\/questions\/base\/2019\/qSEQ19010614G.html<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Coordonn\u00e9es GPS du parking 44.263861 0.710378 Description du site : Historique Construite entre 1997 et 1998 suite aux inondations ayant touch\u00e9 Pont-du-Casse en 1993, cette retenue d\u2019une superficie de 24ha &#8230;<\/p>\n","protected":false},"author":8,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"template-left-sidebar.php","meta":{"footnotes":""},"class_list":["post-183","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/pages\/183","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/comments?post=183"}],"version-history":[{"count":14,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/pages\/183\/revisions"}],"predecessor-version":[{"id":1383,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/pages\/183\/revisions\/1383"}],"wp:attachment":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/lithotheque\/wp-json\/wp\/v2\/media?parent=183"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}