{"id":26255,"date":"2012-03-03T13:53:25","date_gmt":"2012-03-03T08:53:25","guid":{"rendered":"http:\/\/pamirtimes.net\/?p=26255"},"modified":"2012-03-03T13:53:25","modified_gmt":"2012-03-03T08:53:25","slug":"nasa-article-hunzas-new-lake-the-story-behind-the-birth-of-lake-gojal","status":"publish","type":"post","link":"https:\/\/pamirtimes.net\/en\/2012\/03\/03\/nasa-article-hunzas-new-lake-the-story-behind-the-birth-of-lake-gojal\/","title":{"rendered":"[NASA Article] Hunza\u2019s New Lake: The Story Behind the Birth of Lake Gojal"},"content":{"rendered":"

Scientists and satellites hold vigil on a newborn lake in Hunza<\/h3>\n

By Natasha Vizcarra<\/strong><\/p>\n

\u00a0A nervous sense of humor greets travelers at the highest and most scenic road in the world. Hand-painted signs saying, \u201cRelax, slide area ends\u201d dot sections of the Karakoram Highway along the Hunza River in northern Pakistan. Landslides are commonplace here. But on January 4, 2010, a massive rockslide buried part of a village and blocked the river\u2019s flow. Boulders, rocks, and debris tumbled down the mountainside that day, killing twenty people and damming the river until it swelled and swallowed more communities. In months, the plugged-up river would submerge eleven miles of the Karakoram Highway, turning a thriving region buzzing with trade from the Chinese border into scattered clumps of unconnected villages.<\/p>\n

\"\"<\/p>\n

A man stands in the middle of the Karakoram Highway while rocks tumble down into the Hunza River in Pakistan\u2019s Gojal region. The rockslide dammed the river and created Lake Gojal, which submerged eleven miles of the Karakoram Highway and isolated several villages. Photo: Courtesy I. Ali Shimshal\/Pamir Times)<\/p>\n<\/div>\n

When hydrologist Jeffrey Kargel of the University of Arizona saw news footage of the rockslide, he had a hunch the flooded river could swell into a lake. He asked geologist Gregory Leonard to check recent satellite images of the area. \u201cSure enough, there was a lake forming behind the rockslide dam,\u201d said Leonard, Kargel\u2019s colleague at the University of Arizona. \u201cIt\u2019s always startling to see the first images of these kinds of things.\u201d Something else worried Kargel. Three huge glaciers, including the thirty-five-mile long Batura Glacier, are perched on the mountains above the flooded villages. In spring, those glaciers would start gushing melt water down into the new lake. Kargel said, \u201cIf the rockslide dam overflowed and burst, more people downstream would be in harm\u2019s way.\u201d Kargel studies glaciers and the hazards for communities living near them. He had the tools to figure out when the new Lake Gojal would overflow. But he and Leonard had to do it fast, if the information was to be of any help.<\/p>\n

Bathtub model<\/strong><\/p>\n

In many ways, the birth of Lake Gojal was not a surprise. The Hunza River, from which it spawned, sits deep in a mountain valley with extremely steep slopes. \u201cMasses of loose glacial sediment mantle some of these slopes,\u201d Kargel said. The loose gravel, steep slopes, and the water that starts trickling down every spring from the Batura, Pasu, and Ghulkin glaciers have made the region notoriously vulnerable to rockslides and floods. While geologists have found evidence of rockslides that date back to the 1800s, the January 2010 rockslide that thundered into Hunza and snuffed out Attabad village was larger than usual, and finally succeeded in completely cutting off the river. It also cut off the rest of the world. Locals struggled to escape the area, and rescue workers toiled to haul aid and supplies to the isolated villages. With efforts focused on emergency response and disaster preparedness, Kargel and Leonard searched for reports on the new lake in the media and from colleagues.<\/p>\n

\"\"The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA\u2019s Terra satellite captured this false-color image of the landslide lake on the Hunza River on May 2, 2010. Blue indicates water, red indicates vegetation, and shades of beige and gray indicate bare rock. The approximate extent of the lake on March 16, 2010, appears as a white outline. This image has been rotated, so north is to the right. Image: NASA<\/p>\n<\/div>\n

In Arizona, the two researchers decided to make a virtual three-dimensional model of the blocked valley and the lake that was growing inside the valley to determine when water would overflow the dam. They had to figure out how much water was already in it, and how much more was expected to flow into it once the nearby glaciers started sending melt water in the spring. \u201cIt\u2019s like creating a bathtub model of the shape of this valley and the dam itself,\u201d Leonard said. To create the model, they relied on data extracted from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM). They also analyzed a sequence of satellite images taken by the ASTER and Advanced Land Imager (ALI) instruments. The satellite images revealed the lake\u2019s growth and its submergence of the Karakoram Highway and several villages, and how the land around the area had changed before and after the rockslide.<\/p>\n

A swelling lake<\/strong><\/p>\n

Travelers and locals cram into boats and ferries for the two-hour crossing of Lake Gojal. The snow-capped, jagged peaks of Mount Tupopdan are seen in the background. (Courtesy M. Pearson\/ShelterBox)<\/p>\n

They now knew what the shape of the tub looked like; the next challenge was to gauge how much water was flowing into it. Kargel found a thirty-year record of the Hunza River\u2019s rate of flow. \u201cThat data set was really crucial,\u201d he said. With it, they could estimate how much water was flowing into the lake, and how the lake would evolve. To identify the sources of glacier melt water above the valley, they used images from the Global Land Ice Measurements from Space (GLIMS) project. But they still needed to confirm some of the river flow and satellite data with field observations. Geoscientist Jean Schneider was already at Lake Gojal, working as a consultant for Pakistan\u2019s National Disaster Management Authority (NDMA). He described what kind of rocks and soil had tumbled from the mountainside, measured everything that he could, and sent photographs. \u201cInternet access was difficult in the region, so it was hard to get data to and from Jeffrey in the field,\u201d said Schneider, who had to send the data from his office at the University of Vienna.<\/p>\n

\"\"Travelers and locals cram into boats and ferries for the two-hour crossing of Lake Gojal. The snow-capped, jagged peaks of Mount Tupopdan are seen in the background. Courtesy M. Pearson\/ShelterBox)<\/p>\n<\/div>\n

The researchers calculated that the lake\u2019s volume was three to four times larger than what was being reported by the local media. They predicted on April 14, 2010, that the lake would overflow sometime from May 29 to June 1, and that there was a possibility that the rockslide dam would burst. \u201cI was a little alarmed at the difference in our figures and what was being reported,\u201d Kargel said. \u201cSo I approached the U.S. State Department\u2019s Pakistan office, retired Pakistan military authorities who were still connected to the Pakistan NDMA, and I approached Focus Humanitarian Assistance Pakistan. These urgent warnings apparently did reach the authorities in the field and presumably were of some use in planning and preparations for a possible flood.\u201d<\/p>\n

From mid-winter to late spring, disaster management crews had been carving out a spillway to ease the lake\u2019s swelling, and evacuating communities. The growing lake had displaced more than a thousand people and destroyed homes, farms, and fruit orchards in the villages of Shishkat and Gulmit. As it turned out, the overflow began on May 29, and the spilling water soon grew to a torrent.<\/p>\n

Forever or not<\/strong><\/p>\n

\"\"<\/a><\/p>\n

Engineers and army laborers carved a spillway through the dam, and water finally began flowing through it in late May 2010. Although the spillway relieved pressure on the landslide lake, the Hunza Valley did not return to normal. Acquired on August 3, 2011, by the Advanced Land Imager (ALI) on NASA\u2019s Earth Observing-1 (EO-1) satellite, this natural-color image shows the earthen dam and lingering lake behind it. The image is rotated so that north is at right. See enlarged boxed area, below. Image: NASA<\/p>\n<\/div>\n

To the researchers\u2019 surprise, the dam held as the water spilled over. Kargel said, \u201cEverybody concerned, with one exception, was expecting a catastrophe of one magnitude or another.\u201d That exception was hydrologist Victor Baker, Kargel\u2019s colleague at the University of Arizona. Baker was convinced that the dam would hold and that the new lake would remain a lake for many years. \u201cHe believed that the dam\u2019s downstream length was long enough and massive enough to prevent a rapid outburst,\u201d Kargel said. The energy from water spilling over would be dissipated as it traversed the almost mile-long dam and would keep villages downstream safe. The lake would drain slowly and carve out a natural spillway through gradual erosion.<\/p>\n

\u201cIndeed, Baker has so far been correct,\u201d Kargel said. However, Kargel and Leonard are not convinced that the lake is completely harmless. The rockslide dam contains clay from previous glacier melts and landslide-dammed lakes in the valley. Kargel believes the clay could deform over winters and springs as water inside it repeatedly freezes and thaws. Water seeping from within the dam might erode the clay and cause a catastrophic dam burst. Leonard said rockslide dams also typically burst shortly after an overflow. \u201cThis really is a big question,\u201d he said. \u201cWe all wonder if this one is going to last a long time.\u201d<\/p>\n

Waiting game<\/strong><\/p>\n

As scientists debate Lake Gojal\u2019s life expectancy, people displaced by the lake are scrambling for ways to live with it. Parts of the Karakoram Highway remain impassable, but boats and ferries now crowd makeshift docks at the lake\u2019s spillway and at the northernmost shore in Hussaini village. However, the two-hour lake crossing is uncomfortable and somewhat dangerous. Boats are crammed with passengers, animals, and goods beyond their capacity. Sometimes, it is just not possible to travel to the isolated villages. \u201cPeople can cross the lake only during daytime and when the weather is good,\u201d said rescue volunteer Rehmat Ali Tajik. Locals wait for word of when Karakoram Highway will be repaired. Local journalist Noor Muhammad said, \u201cThere is a hope that roads will be constructed sooner or later. People know that the Karakoram Highway is very important to Pakistan and China.\u201d<\/p>\n

\"\"<\/p>\n

A close-up of the boxed area from the previous image. The image is rotated so that north is at right. Geologist David Petley (International Landslide Centre at Durham University) has tracked the effects of the Hunza landslide since January 2010. He concluded that the Hunza lake levels probably stabilized by early July 2010, thanks to the spillway. Over the following 13 months, water flowing through the spillway eroded the landslide dam, widening the flow channel. Yet flow out of the lake and down the river valley remained constrained by the narrow inlet through the dam crest. Between July 2010 and August 2011, that crest changed little, Petley observed. Image: NASA<\/p>\n<\/div>\n

Meanwhile, the lake needs watching. Locals fear that Lake Gojal still holds a dangerous amount of water and have used hand tools to widen the spillway themselves. \u201cThe spillway has just not been able to bring the water level down considerably,\u201d Muhammad said. Unusually warm weather could bring more water from the glaciers down to the lake. Kargel and his colleagues continue to distrust the dam. \u201cThe lake remains dangerous, in my opinion,\u201d Kargel said. \u201cWe will keep a satellite\u2019s eye view on the situation.\u201d It may turn out to be a long vigil. \u201cThis lake could go at any time, or it could just last for centuries,\u201d he said.<\/p>\n

Date posted:<\/em>\u00a0Friday, March 2, 2012<\/p>\n

This article was originally featured in the 2011\u00a0issue of\u00a0Sensing Our Planet<\/em>, a NASA publication. For more information, see\u00a0references below.<\/p>\n

________________<\/p>\n

About the scientists:<\/em><\/p>\n

\"\"<\/a>Jeffrey Kargel is a hydrologist and senior associate research scientist at the University of Arizona. He also serves as the coordinator for the Global Land Ice Measurements from Space (GLIMS) project. Kargel became interested in glaciers through his research on the Martian cryosphere and its geologic and climatic history. NASA supported his research. (Photograph courtesy J. Kargel).<\/p>\n

\"\"Gregory Leonard is a geologist and assistant research scientist in the Department of Hydrology and Water Resources at the University of Arizona. As a member of the GLIMS project, he applies remote sensing and Geographic Information System (GIS) science with field glaciological studies to monitor the changing state of alpine glaciers in Alaska and the Himalaya. NASA supported his research. (Photograph courtesy G. Leonard)<\/p>\n

References:<\/em><\/p>\n

1. The article is featured in the 2011 edition of\u00a0 NASA\u2019s annual print publication\u00a0Sensing Our Planet<\/em>, produced at\u00a0The National Snow and Ice Data Center<\/em>\u00a0(www.nscidc.org<\/a>).\u00a0The article arose from research that used data from NASA Earth Observing System Data and Information System (EOSDIS) data centers. To download a PDF version of the publication please\u00a0click\u00a0Sensing Our Planet<\/a>.\u00a0<\/em>To request printed copies please send an email to\u00a0nsidc@nsidc.org<\/a>.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Scientists and satellites hold vigil on a newborn lake in Hunza By Natasha Vizcarra \u00a0A nervous sense of humor greets travelers at the highest and most scenic road in the world. Hand-painted signs saying, \u201cRelax, slide area ends\u201d dot sections of the Karakoram Highway along the Hunza River in northern Pakistan. Landslides are commonplace here. …<\/p>\n","protected":false},"author":1,"featured_media":26256,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_forum_subforum_count":0,"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"jetpack_seo_schema_type":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[56],"tags":[6,568,837,588],"class_list":["post-26255","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-gilgit-baltistan","tag-hunza","tag-lake","tag-lake-gojal","tag-lake-in-hunza"],"better_featured_image":{"id":26256,"alt_text":"","caption":"","description":"","media_type":"image","media_details":{"width":"690","height":"345","hwstring_small":"height='64' width='128'","file":"2012\/03\/hunza_ali_2011215_2.jpg","sizes":{"thumbnail":{"file":"hunza_ali_2011215_2-150x150.jpg","width":"150","height":"150","source_url":"https:\/\/i0.wp.com\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2.jpg?resize=150%2C150&ssl=1"},"medium":{"file":"hunza_ali_2011215_2-300x150.jpg","width":"300","height":"150","source_url":"https:\/\/i0.wp.com\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2.jpg?fit=300%2C150&ssl=1"},"post-thumbnail":{"file":"hunza_ali_2011215_2-50x50.jpg","width":"50","height":"50","source_url":"https:\/\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2-50x50.jpg"},"415x260":{"file":"hunza_ali_2011215_2-415x260.jpg","width":415,"height":260,"source_url":"https:\/\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2-415x260.jpg"},"150x150":{"file":"hunza_ali_2011215_2-150x150.jpg","width":150,"height":150,"source_url":"https:\/\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2-150x150.jpg"},"120x85":{"file":"hunza_ali_2011215_2-120x85.jpg","width":120,"height":85,"source_url":"https:\/\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2-120x85.jpg"}},"image_meta":{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":""}},"post":26255,"source_url":"https:\/\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2.jpg"},"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack_featured_media_url":"https:\/\/i0.wp.com\/pamirtimes.net\/wp-content\/uploads\/2012\/03\/hunza_ali_2011215_2.jpg?fit=690%2C345&ssl=1","_links":{"self":[{"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/posts\/26255","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/comments?post=26255"}],"version-history":[{"count":1,"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/posts\/26255\/revisions"}],"predecessor-version":[{"id":26257,"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/posts\/26255\/revisions\/26257"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/media\/26256"}],"wp:attachment":[{"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/media?parent=26255"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/categories?post=26255"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pamirtimes.net\/en\/wp-json\/wp\/v2\/tags?post=26255"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}