{"id":11415,"date":"2014-09-08T10:05:03","date_gmt":"2014-09-08T10:05:03","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=11415"},"modified":"2014-09-08T10:05:03","modified_gmt":"2014-09-08T10:05:03","slug":"the-sunkoshi-landslide-dam-breach","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2014\/09\/08\/the-sunkoshi-landslide-dam-breach\/","title":{"rendered":"The Sunkoshi landslide dam breach"},"content":{"rendered":"<h5>The Sunkoshi landslide dam breach event<\/h5>\n<p>On Saturday night, apparently without warning, the landslide dam on the Sunkoshi River in Nepal abruptly breached, allowing the lake to mostly drain.\u00a0 This event appears to have occurred without warning, such that one of the Nepal Army excavators was washed away.\u00a0 The breach event appears to have been natural &#8211; a response to heavy rainfall &#8211; rather than a result of the attempts by the Nepal Army to widen the channel.\u00a0 <a href=\"http:\/\/www.ekantipur.com\/2014\/09\/08\/headlines\/Sunkoshi-bursts-landslide-dam\/394724\/\">Whilst some damage has been reported downstream<\/a>, the flood does not appear to have been exceptionally large, so no casualties have been reported. <a href=\"http:\/\/www.myrepublica.com\/portal\/index.php?action=news_details&amp;news_id=82612\">Republica<\/a> has a very nice set of photographs of the breached lake and dam:<\/p>\n<div id=\"attachment_11416\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-1.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-11416\" class=\"size-full wp-image-11416\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-1.jpg\" alt=\"Sunkoshi landslide dam breach\" width=\"490\" height=\"276\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-1.jpg 490w, https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-1-300x168.jpg 300w\" sizes=\"auto, (max-width: 490px) 100vw, 490px\" \/><\/a><p id=\"caption-attachment-11416\" class=\"wp-caption-text\"><a href=\"http:\/\/www.myrepublica.com\/portal\/index.php?action=news_details&amp;news_id=82612\">Republica<\/a><\/p><\/div>\n<div id=\"attachment_11417\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-2.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-11417\" class=\"size-full wp-image-11417\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-2.jpg\" alt=\"Sunkoshi landslide dam breach\" width=\"490\" height=\"276\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-2.jpg 490w, https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-2-300x168.jpg 300w\" sizes=\"auto, (max-width: 490px) 100vw, 490px\" \/><\/a><p id=\"caption-attachment-11417\" class=\"wp-caption-text\"><a href=\"http:\/\/www.myrepublica.com\/portal\/index.php?action=news_details&amp;news_id=82612\">Republica<\/a><\/p><\/div>\n<div id=\"attachment_11418\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-3.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-11418\" class=\"size-full wp-image-11418\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-3.jpg\" alt=\"Sunkoshi landslide dam breach\" width=\"490\" height=\"276\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-3.jpg 490w, https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-3-300x168.jpg 300w\" sizes=\"auto, (max-width: 490px) 100vw, 490px\" \/><\/a><p id=\"caption-attachment-11418\" class=\"wp-caption-text\"><a href=\"http:\/\/www.myrepublica.com\/portal\/index.php?action=news_details&amp;news_id=82612\">Republica<\/a><\/p><\/div>\n<p>.<\/p>\n<p>Whilst Kapil Dhital (@bewitchkapil) <a href=\"pic.twitter.com\/6AGL4JdBx9\">tweeted this image of the lake this morning<\/a>:<\/p>\n<div id=\"attachment_11419\" style=\"width: 350px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-4.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-11419\" class=\"size-full wp-image-11419\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-4.jpg\" alt=\"Sunkoshi landslide dam breach\" width=\"340\" height=\"255\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-4.jpg 340w, https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-breach-4-300x225.jpg 300w\" sizes=\"auto, (max-width: 340px) 100vw, 340px\" \/><\/a><p id=\"caption-attachment-11419\" class=\"wp-caption-text\">Khapil Dhital (@bewitchkapil) via Twitter<\/p><\/div>\n<p><script src=\"\/\/platform.twitter.com\/widgets.js\" async=\"\" charset=\"utf-8\"><\/script><\/p>\n<p>.<\/p>\n<p>So what caused the breach?\u00a0 This is the gauging data for the Bharabise station (upstream of the dam) and the Pachuwaghat station (downstream).\u00a0 Note that the two sets of data use different y-axes. The flood peak generated by the breach event is very clear at Pachuwarghat, although this is not a very high peak.\u00a0 The Bharabise station probably responded to rainfall &#8211; there is a dramatic increase in discharge a few hours before the flood wave reached Pachuwarghat.\u00a0 Thus, it appears that the breach was initiated by this sudden increase in river flow in response to heavy rainfall:<\/p>\n<p><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-discharge-1.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter  wp-image-11420\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-discharge-1.gif\" alt=\"Sunkoshi landslide dam breach\" width=\"437\" height=\"361\" \/><\/a>.<\/p>\n<p>This is clearer when the data for the few hours before the breach event are plotted:<\/p>\n<p><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-discharge-2.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-11421\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/09\/14_09-Sunkoshi-discharge-2.gif\" alt=\"Sunkoshi landslide dam breach\" width=\"438\" height=\"360\" \/><\/a><\/p>\n<p>.<\/p>\n<p>In many ways this is the best possible outcome.\u00a0 The release of most of the water means that the hazard has in effect been removed, but without causing a huge amount of damage downstream.\u00a0 Unfortunately the huge amount of resource and effort that has gone into building the two new roads has been wasted.\u00a0 Once again I would reiterate my opinion that a focus on deepening the channel, rather than widening it and building new roads, would have been a much more effective way to manage this hazard.\u00a0 That the dam breached in a rainfall-induced event suggests that a targeted effort to deepen the channel could have resolved the crisis much earlier.<\/p>\n<!-- AddThis Advanced Settings generic via filter on the_content --><!-- AddThis Share Buttons generic via filter on the_content -->","protected":false},"excerpt":{"rendered":"<p>The Sunkoshi landslide dam in Nepal breached and drained early on Sunday morning.  The discharge data suggests that the breach was initiated in response to increased river flow caused by heavy rainfall.<!-- AddThis Advanced Settings generic via filter on wp_trim_excerpt --><!-- AddThis Share Buttons generic via filter on wp_trim_excerpt --><\/p>\n","protected":false},"author":22,"featured_media":11420,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[469,15,959,66,72,800],"class_list":["post-11415","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-featured","tag-landslide-dam","tag-landslide-report","tag-nepal","tag-south-asia","tag-sunkoshi"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/11415","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=11415"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/11415\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/11420"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=11415"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=11415"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=11415"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}