{"id":21685,"date":"2017-02-14T07:36:29","date_gmt":"2017-02-14T07:36:29","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=21685"},"modified":"2017-02-14T07:36:29","modified_gmt":"2017-02-14T07:36:29","slug":"oroville-dam-site","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2017\/02\/14\/oroville-dam-site\/","title":{"rendered":"The enormous scale of the erosion problem at the Oroville Dam site"},"content":{"rendered":"<h5>The scale of the erosion problem at the Oroville Dam site<\/h5>\n<p>As the fairly desperate attempt continue to shore up the spillways at the Oroville Dam site, and to lower the water level ahead of the next rainstorm, better images are emerging of the scale of the problems on both spillways.\u00a0 If we start with the main spillway, which suffered the original erosion events last week, it is hard to appreciate the serious nature of the problems.\u00a0 However, this image (via the <a href=\"http:\/\/www.sacbee.com\/news\/state\/california\/water-and-drought\/article131579999.html\">Sacramento Bee<\/a>) from the weekend shows workers in the hole eroded in the main channel:-<\/p>\n<div id=\"attachment_21695\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-21695\" class=\"size-full wp-image-21695\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/02\/17_02-Oroville-8-e1487056247256.jpg\" alt=\"Oroville Dam site\" width=\"640\" height=\"360\" \/><p id=\"caption-attachment-21695\" class=\"wp-caption-text\">The spillway hole at the Oroville Dam site, via the <a href=\"http:\/\/www.sacbee.com\/news\/state\/california\/water-and-drought\/article131579999.html\">Sacramento Bee<\/a><\/p><\/div>\n<p>.<\/p>\n<p>Of course the high flows down the spillway since then are likely to have exacerbated the problem significantly.\u00a0 Meanwhile, the headward erosion problem in the emergency spillway is now garnering most of the attention, primarily because of the potential for a major collapse.\u00a0 This image, from <a href=\"http:\/\/hamodia.com\/2017\/02\/13\/nearly-200000-evacuees-may-not-go-home-dam-repaired\/\">Hamodia<\/a>, shows the nature of the erosion that has developed at multiple locations immediately down slope of the emergency spillway at the Oroville dam site:<\/p>\n<div id=\"attachment_21704\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-21704\" class=\"size-full wp-image-21704\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/02\/17_02-Oroville-9-e1487056577979.jpg\" alt=\"Oroville dam site\" width=\"640\" height=\"391\" \/><p id=\"caption-attachment-21704\" class=\"wp-caption-text\">Erosion below the emergency spillway at the Oroville Dam site, via <a href=\"http:\/\/hamodia.com\/2017\/02\/13\/nearly-200000-evacuees-may-not-go-home-dam-repaired\/\">Hamodia<\/a><\/p><\/div>\n<p>.<\/p>\n<p>The most serious problem appears to be a gully towards the bottom of the image, but there is also substantial amounts of erosion occurring on the other side too.\u00a0 The danger is of course that the these gullies will suffer headward erosion until they undermine the spillway lip. whereupon collapse may occur.\u00a0 One challenge is that the quality of the rock does not appear to be high, which accounts for the rapid erosion in both cases.\u00a0 This image, <a href=\"https:\/\/twitter.com\/kenricnowell\/status\/831202317269561344\">via Twitter<\/a>, shows the nature of the bedrock with which the crews are dealing:-<\/p>\n<div id=\"attachment_21716\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-21716\" class=\"size-full wp-image-21716\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/02\/17_02-Oroville-10-e1487057170716.jpg\" alt=\"Oroville Dam site\" width=\"640\" height=\"360\" \/><p id=\"caption-attachment-21716\" class=\"wp-caption-text\">The nature of the bedrock in the spillways at the Oroville Dam site, via <a href=\"https:\/\/twitter.com\/kenricnowell\/status\/831202317269561344\">Twitter<\/a><\/p><\/div>\n<p>.<\/p>\n<p>The challenges are substantial.\u00a0 Fortunately, as before, there is no threat to the dam itself.<\/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>Images that have appeared online over the last 24 hours dramatically illustrate the vast scale of the erosion problem at the Oroville dam site<!-- 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":21695,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[137,71,61,325,292,469,2054,48],"class_list":["post-21685","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-california","tag-dam","tag-emergency","tag-erosion","tag-evacuation","tag-featured","tag-oroville","tag-usa"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/21685","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=21685"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/21685\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/21695"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=21685"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=21685"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=21685"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}