The people and governments of Nepal and India had simply assumed the structure would not fail. And yet, there was already a long and tragic history of river embankment breaches in both countries.<\/p>\n In pre-colonial north India, farmers and zamindars<\/em> (landlords) sometimes constructed earthen embankments known as bundhs<\/em> along short stretches of rivers to protect small tracts of land from flooding for certain periods of time. But historical accounts suggest such constructions were intentionally ephemeral, and never aimed to fully eliminate floods.\u00a0 Rather, many farmers depended on occasional river floods to deposit silt and organic matter from upper catchments in their fields, providing nourishment to crops before the age of modern chemical fertilisers. Floods sometimes entered villages and damaged homes, but because the current was usually slow and water was able spread over extensive plains, the damage was often limited.<\/p>\n The British built the first large-scale embankments in South Asia aimed at permanently preventing floods. They often contracted with local zamindars or tax collectors, who in turn organised the labour to build extended earthen bundhs for long sections of flood-prone rivers. While official rhetoric emphasised the benefits for poor farmers, the colonial rulers also had certain self-interests in mind.\u00a0 In the Mahanadi delta of Orissa, for example, the historian Rohan D\u2019Souza has argued that the British attempted to control meandering waterways to delineate property<\/a> more clearly and strengthen the role of tax-collecting authorities.\u00a0 This helped usher into the world of colonial capitalism what he called a \u201cflood-dependent agrarian regime\u201d The British also built embankments to protect infrastructure. In the 1850s, they undertook perhaps their most ambitious project \u2013 the embankment of a section of the Damodar river, west of the colonial capital Calcutta (now Kolkatta), to protect a new railway.<\/p>\n But problems soon emerged.\u00a0 Farmers complained that the lack of silt hurt agricultural yields. And embankments prevented water outside of rivers from draining into the rivers, causing and prolonging floods. What\u2019s more, when the embankments broke – which, absent constant maintenance and reinforcement, they inevitably did – they unleashed waters into surrounding territories at high velocities, causing much more damage than slow-rising floods historically had.\u00a0 Because they were so unsuccessful at preventing floods, most of the Damodar embankments had to be demolished within a decade<\/a> of their construction.<\/p>\n These problems were exacerbated by a particularly irksome nuisance: sediment.<\/p>\n Several major tributaries of the Ganga in northern Bihar, which descend from the eastern Himalaya in Nepal, were particularly notorious for sediment. The largest, the Koshi, has a catchment area of nearly sixty-thousand square kilometres in the Tibetan plateau and Nepali mountains before debouching into the plains. In its upper reaches, the water carries large quantities of earth \u2013 \u201calluvium\u201d \u2013 eroded from the mountains and hills.\u00a0 Although the science of calculating river sediment loads is imprecise, modern studies suggest the river carries between 80 million<\/a> and 120 million<\/a> cubic meters of sediment per year, or a cubic kilometre every eight to 12 years.<\/p>\n Once the river reaches the plains it slows down, and riverine \u201chitch-hikers\u201d begin to drop out of the water column and settle: first the largest stones, followed by sand, then silt, and progressively smaller particles as the velocity decreases. This deposition leads the river bed to continually rise, and so the river seeks to change course, always looking for lower ground, creating one of the largest alluvial fans<\/a> in the world.<\/p>\n Between the mid-18th century and the mid-20th century, the Koshi migrated over 100 kilometres westward, abandoning old channels and forming new ones.\u00a0 Along with mercurial water flow \u2013 the Koshi\u2019s typical monsoon-season discharge is five to ten times its dry-season discharge<\/a> \u2013 sediment contributed to flooding.<\/p>\n But sediment also complicated British flood-control efforts.\u00a0 When they attempted to build embankments along small sections of the river, the river bed began to rise faster than before because the deposited alluvium had less space to spread out. This resulted in the river becoming super-elevated relative to the surrounding floodplain, making breaches all the more dangerous.<\/p>\n However, official opposition to embankments did not last long.<\/p>\n Mishra shows that flood-control policy experienced a quick about-face following Indian independence. Public and media attention initially turned to an idea that had been floated as early as 1937 – to build a high dam that could hold back flood waters at Barahakshetra in Nepal, where the Koshi debouches from the hills. However, an Indian government committee declared the dam infeasible in 1951 (it would have cost INR 1.77 billion – an astronomical sum at the time when the Indian rupee was almost at par with the US dollar – \u00a0and taken nearly two decades to build).<\/p>\n In 1953, devastating floods hit the Koshi and, amid public pressure for the government to act, embankments gained favour once again. After Prime Minister Nehru toured affected areas, his government announced a plan for a \u201cKoshi Scheme\u201d to embank nearly 150 kilometres of the river from near the base of the Himalayas in Nepal to near its confluence with the Ganga in Bihar.<\/p>\n The decision to build the embankments was based on what Mishra euphemistically calls \u201cextra-technical\u201d considerations. He notes that the government sent engineers on trips to the Yellow River in China and the Mississippi in the US to assess the feasibility of embanking large rivers. But in fact, the feasibility trips occurred only after the Koshi Scheme had essentially been approved. Foreign counterparts in both the US and China recommended the Indians consider the effects of siltation carefully.\u00a0 The Indian engineers seemed to ignore serious problems on the rivers they visited: both the Mississippi and Yellow had experienced embankment breaches and devastating floods in recent decades. (For example, in 1938, Chiang Kai Shek\u2019s Nationalist Army cut through embankments on the Yellow to induce a flood to halt oncoming Japanese imperial troops, killing nearly a million people<\/a>. Though it was intentional, the flood was all the more destructive because of the Yellow\u2019s super-elevation relative to the surrounding land.)<\/p>\n The scheme \u2013 redubbed the Koshi Project \u2013 moved ahead.\u00a0 Embankment construction commenced in 1955, and continued until 1959.<\/p>\n The construction work utilized heavy earth-moving equipment and also mobilized over a million labourers who worked with picks, shovels and baskets to dig and move earth to build the earthen walls. To slow the flow of water near the edge and reduce the river\u2019s ability to erode the embankments, they were studded with \u201cspurs\u201d \u2013 pier-like projections 100 to 300 metres long pointing in towards the river, placed roughly every half-kilometre, buttressed at their base and sides with boulders and metal fencing.<\/p>\n Initially there was widespread excitement about the Koshi Project. Globally, large infrastructure projects \u2013 like the Hoover and Coulee dams in the American West \u2013 were seen as symbols of national pride and unity. In Bihar, the Bharat Sevak Samaaj organized tens of thousands of volunteers – including \u201cstudents, policemen, and sadhus\u201d – to contribute to the earth-moving campaign. A government-produced documentary film declared that with the completion of the project, \u201ca wild, capricious river will have been tamed\u2026The present gives but an inkling of a brighter future.\u00a0 The harvest will increase.\u00a0 The land will grow more fertile. And the river will be a herald of plenty\u2026For the people of this region, the harnessing of the Koshi river will mean the end of a long and tragic drama.\u201d<\/p>\n![\"locals](\"https:\/\/dialogue.earth\/content\/uploads\/2018\/08\/IMG_9479-1.jpg\")
A history of embankments<\/h2>\n
Sediment \u2013 from silt to sorrow<\/h2>\n
![\"map](\"https:\/\/dialogue.earth\/content\/uploads\/2018\/08\/koshi-fan.jpg\")
Post-Independence boost<\/h2>\n
The Koshi Project<\/h2>\n