The Bagmati River runs down from the Himalayan midhills surrounding Kathmandu Valley, entering India at the Sitamarhi District of Bihar. In Khagaria District, the river joins up with the Kosi River near Badla Ghat. The Bagmati's total catchment area of nearly 13,300 sq km is divided roughly evenly between India and Nepal, and its basin is among the world's most fertile regions, mainly due to the significant amount of silt carried by the river. The slope of the ground through which the river moves flattens out almost entirely once it enters the Gangetic plains, where the river's heavy silt load causes the Bagmati to meander.
South of the border, hydrologists divide the flow of the Bagmati into three distinct segments, each around 90 km in length. The lower reaches, although prone to overflow, are considered to be relatively stable, and hence were embanked during the mid-1950s in an attempt to solve the flood problems in that area. At that time, the upper and middle segments were left alone, with officials saying that it was unwise to embank the unstable portions of the river.
Yet even while this conclusion was being drawn, one of the most unstable rivers in the country, the much larger Kosi, was being embanked just to the east – a decision that drew wide acclaim from the local communities. To the west of the Bagmati, an ambitious irrigation project on the Gandak River was launched at the initiative of India's first president, Rajendra Prasad. Sandwiched between these massive projects, community leaders in the Bagmati basin had little to boast about. Thus they came under compulsion to demand an embankment project of their own. Local farmers were opposed to any such move, warning that their productivity would suffer if their lands were deprived of the yearly addition of fertile silt that came along with the floods. They also noted that the inconvenience posed by the monsoonal floods was relatively modest, with the inundations never lasting for longer than two or three days at a stretch.
Such protests fell on deaf ears, amidst politicians and bureaucrats who knew only the logic of man-made 'training' of rivers. By 1965, official efforts had begun to tame the Bagmati in its upper stretches, including a proposal to build embankments at an estimated cost of INR 31.7 million. Over the next two decades this estimate was revised upwards several times, ultimately to around INR 604.8 million by 1981. Despite local resistance, roughly 85 km of embankments were constructed during the 1975-77 State of Emergency under Indira Gandhi, from Dheng (near the Indo-Nepali border) to Runni Saidpur.