{"id":10938,"date":"2014-08-18T21:54:31","date_gmt":"2014-08-18T21:54:31","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=10938"},"modified":"2014-08-18T21:54:31","modified_gmt":"2014-08-18T21:54:31","slug":"sunkoshi-landslide-18-08","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2014\/08\/18\/sunkoshi-landslide-18-08\/","title":{"rendered":"Sunkoshi landslide: another update"},"content":{"rendered":"<h5>Sunkoshi landslide<\/h5>\n<p>ICIMOD has released a report about the <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2014\/08\/15\/landslide-turmoil-in-nepal\/\">Sunkoshi landslide<\/a>, which has been <a href=\"https:\/\/owa.dur.ac.uk\/owa\/redir.aspx?C=9DUXrRGcO0unaSt84JZfW2Y4FUeGjdEISYNJ_c4ZzSSuUrWk_WQCoSwybzJusZscgZeWjclEX4A.&amp;URL=http%3a%2f%2fwww.thehimalayantimes.com%2ffullNews.php%3fheadline%3dScientific%2bstudies%2bsuggested%2bat%2bSindhupalchok%2blandslip%2bsite%2b%26NewsID%3d424548%26a%3d3\">reported in The Himalayan Times<\/a>.\u00a0 The most interesting aspect may be some statistics on the landslide, which appeared in a<a href=\"https:\/\/twitter.com\/KanakManiDixit\/status\/501183729369243648\"> tweet by Kanak Mani Dixit<\/a>, which said:<\/p>\n<blockquote class=\"twitter-tweet\" lang=\"en\"><p>ICIMOD collation re Sunkosi landslide: dam length 409m, width 106m, height 55m, volume\/material: 6mill m3, lake length 3km, volume 8mill m3.<\/p>\n<p>\u2014 Kanak Mani Dixit (@KanakManiDixit) <a href=\"https:\/\/twitter.com\/KanakManiDixit\/statuses\/501183729369243648\">August 18, 2014<\/a><\/p><\/blockquote>\n<p><script src=\"\/\/platform.twitter.com\/widgets.js\" async=\"\" charset=\"utf-8\"><\/script>.<\/p>\n<p>These statistics are in line with those generated elsewhere, but are the first to provide a complete set.\u00a0 The main thrust of the ICIMOD report (which I&#8217;ve not seen) seems to be that more investigation of the Sunkoshi landslide itself, and more detailed landslide hazard mapping in general, are required.\u00a0 It is hard to disagree with these suggestions.<\/p>\n<p>Meanwhile, the Nepal Army continue to try to drain the lake, but the degree to which they are being successful is very unclear.\u00a0 There is a profound deficit of reliable information about the state of play at the dam site &#8211; over the last two weeks there has been a number of reports that the lake level was falling, all of which have proven to be incorrect.\u00a0 <a href=\"https:\/\/owa.dur.ac.uk\/owa\/redir.aspx?C=9DUXrRGcO0unaSt84JZfW2Y4FUeGjdEISYNJ_c4ZzSSuUrWk_WQCoSwybzJusZscgZeWjclEX4A.&amp;URL=http%3a%2f%2fwww.myrepublica.com%2fportal%2findex.php%3faction%3dnews_details%26news_id%3d81153\">The latest reports<\/a>, on Sunday, were that:<\/p>\n<blockquote><p><span lang=\"EN-US\">The water level in artificial lake formed after massive landslide at Jure blocked Sunkoshi River, is gradually decreasing with increase in water outflow from the reservoir after Nepal Army (NA) constructed another channel to drain out dammed water.\u00a0 <\/span>Decline in water level could be clearly witnessed on Sunday as clouds separated revealing blue sky after three days of torrential downpour came to an end.<\/p>\n<p>According to NA Brigadier General Ashwin Kumar Thapa, the water level has decreased by 75 centimeters after excavators were used to increase water outflow. \u201cThe water level in the dam is decreasing at the rate of two centimeters per hour,\u201d he said.\u00a0 He further informed that water inflow in the artificial lake is 180-200 cusec, while outflow of water from the reservoir is 350 cusec. \u201cThe current water inflow rate is normal rate for Sunkoshi River during Monsoon,\u201d he said.<\/p>\n<p>During three-days of torrential downpour both water inflow and outflow were high with outflow and inflow rate standing at 330 causes and 530 causes respectively.<\/p><\/blockquote>\n<p><span lang=\"EN-US\">But what does this mean?\u00a0 The figures above suggest that during the heavy rainfall the inflow exceeded the outflow, which means that the lake level must have risen.\u00a0 Then, when the rain stopped the inflow reduced to a level below outflow, so the lake level must have fallen.\u00a0 This is quite normal dam hydraulics.\u00a0 A key question is whether the net (i.e. low flow) level of the lake has fallen.\u00a0 The data being provided are not adequate to judge this.\u00a0 <\/span><\/p>\n<p><span lang=\"EN-US\">The key to reducing the level of the lake has to be to lower the bed of the channel.\u00a0 Widening the channel, or creating a new one, will make the discharge of storm flow more efficient &#8211; i.e. the lake level won&#8217;t rise so much in the next heavy rainfall event.\u00a0 But to meaningfully draw down the lake the channel bed has to be lowered.\u00a0 Now this is of course risky &#8211; in particular if the bed of the stream is being armoured by large boulders, then these have to be blasted.\u00a0 But, this could be the case that beneath the boulders lie fine-grained deposits that might erode quickly once exposed.\u00a0 So this sort of operation is very sensitive and challenging, and requires high levels of expertise.\u00a0 And this is why I still contend that the Nepal Army should be seeking assistance from groups that have managed these problems before, most notably the Chinese.\u00a0 They might note the <a href=\"http:\/\/news.xinhuanet.com\/english\/china\/2014-08\/13\/c_126863368.htm\">speed and efficiency of the operation to drain the valley blocking landslide in Yunnan Province<\/a>, despite the very challenging access problems.<br \/>\n<\/span><\/p>\n<p>If the Nepal Army wants to drain the lake then the engineers have to deepen the channel.\u00a0 The challenge is to do this is a safe way. Why not get assistance from the Chinese team whose raison d&#8217;etre is to manage valley blocking landslides?\u00a0 After all, China wants this important trade link open too.<\/p>\n<p>Finally, an additional dimension is the rapidly escalating pressure to reopen the road to Tibet.\u00a0 The <a href=\"http:\/\/www.ekantipur.com\/2014\/08\/18\/national\/engineers-association-submit-draft-to-pm-koirala\/393766.html\">Nepal Engineers Association is pressing<\/a> for concerted efforts to drain the lake and construct an alternative road to bypass the Sunkoshi landslide.\u00a0 In a separate development, a group of local entrepreneurs have started to construct a new alignment with a bulldozer:<\/p>\n<p><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/08\/14_08-Sunkoshi-dozer-e1408397657668.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-10939\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/08\/14_08-Sunkoshi-dozer-e1408397657668.jpg\" alt=\"sunkoshi landslide\" width=\"640\" height=\"484\" \/><\/a>.<\/p>\n<p>Whilst I can understand the frustration that is driving this, the track shown above is both environmentally catastrophic and a recipe for further landslides.\u00a0 It seems unlikely that it is a sustainable solution.<\/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>An update on the valley-blocking Sunkoshi landslide in Nepal, where efforts to drain the lake continue to proceed slowly amidst growing signs of unrest about the loss of the trade route to Tibet<!-- 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":10939,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[469,15,66,800,113,688],"class_list":["post-10938","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-featured","tag-landslide-dam","tag-nepal","tag-sunkoshi","tag-tibet","tag-valley-blocking-landslide"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/10938","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=10938"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/10938\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/10939"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=10938"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=10938"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=10938"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}