{"id":22150,"date":"2017-03-07T07:24:03","date_gmt":"2017-03-07T07:24:03","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=22150"},"modified":"2017-03-07T07:24:03","modified_gmt":"2017-03-07T07:24:03","slug":"feather-river-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2017\/03\/07\/feather-river-1\/","title":{"rendered":"Oroville dam: multiple riverbank failures on the Feather River after the flow was abruptly stopped"},"content":{"rendered":"
Oroville dam: multiple riverbank failures on the Feather River after the flow was abruptly stopped<\/h5>\n

The San Francisco Chronicle<\/a> has an excellent article about what happened next on the Feather River when the flow down the Oroville Spillway was abruptly stopped last week to remove debris from the channel:<\/p>\n

When state water officials scaled back their mass dumping of water from the damaged Oroville Dam this week, they knew the riverbed below would dry up enough to allow the removal of vast piles of debris from the fractured main spillway.\u00a0 But they apparently did not anticipate a side effect of their decision to stop feeding the gushing Feather River \u2014 a rapid drop in river level that, according to downstream landowners, caused miles of embankment to come crashing down.\u00a0 With high water no longer propping up the shores, the still-wet soil crashed under its own weight, sometimes dragging in trees, rural roads and farmland, they said.<\/p>\n

\u201cThe damage is catastrophic,\u201d said Brad Foster, who has waterfront property in Marysville (Yuba County), about 25 miles south of Lake Oroville.<\/p>\n

The farmer not only saw 25-foot bluffs collapse, but also lost irrigation lines to his almonds. \u201cWhen the bank pulled in,\u201d he said, \u201cit pulled the pumps in with it. It busted the steel pipes.\u201d<\/p><\/blockquote>\n

In the article, farmers describe losing substantial sections of their riverbank.\u00a0 For example one, Philip Filter at Live Oak describes losing most of the banks in his section, which extends over a kilometre.\u00a0 This image shows some of the damage:<\/p>\n

\"Feather

Landslides on the Feather Rover caused by the rapid drawdown of flow from the Oroville Dam, via the San Francisco Chronicle<\/a><\/p><\/div>\n

.<\/p>\n

Meanwhile on Twitter, Mike Luery of KCRA3 has provided another example<\/a> of a riverbank collapse on the Feather River:<\/p>\n

\"Feather

A riverbank failure on the Feather River, via Mike Luery of KCRA3 on Twitter<\/a><\/p><\/div>\n

.<\/p>\n

Riverbank collapse during rapid draw down\u00a0 is a well-known phenomenon – indeed riverbank failures are most likely on the falling limb of the hydrograph.\u00a0 As the river level rapidly falls the banks are left in a saturated state, which means that they are weak.\u00a0 But more importantly, they also have a hydraulic imbalance, which drives flow of water through the soil towards the river.\u00a0 This provides an additional force that reduces stability.<\/p>\n

The problems of riverbank failure are well-described in the literature, and there is even a Wikipedia page<\/a> that provides a detailed description.\u00a0 The tragedy is of course that\u00a0 riverbank failures represent a permanent loss of land, and the input of sediment into the river can have implications for the ecosystem.\u00a0 Drawing the river down more slowly means that the hydraulic instability is avoided, and the riverbank failures should not occur.<\/p>\n","protected":false},"excerpt":{"rendered":"

The rapid drawdown of the water level in the Feather River when the Oroville Dam flow was stopped last week induced multiple riverbank failures downstream<\/p>\n","protected":false},"author":22,"featured_media":22167,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_members_access_role":[],"_members_access_error":""},"categories":[3],"tags":[137,71,469,959,725,524,48],"class_list":["post-22150","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-california","tag-dam","tag-featured","tag-landslide-report","tag-north-america","tag-riverbank","tag-usa"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/22150","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=22150"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/22150\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/22167"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=22150"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=22150"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=22150"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}