south to empty into the Bay of Bengal through an estuary about wide. Ain-i-Akbari, a book by Abu'l-Fazl, describes that the river Ganga and river Sarwasati (Sarsuti) streams of lower Bengal had different flows. According to the footnotes of this book, the colour of the water of the Sarawasati was white, the colour of another stream named Jamuna was blue, and the colour of the Ganga was muddy and yellowish. From Kolkata the main flow of the Hooghly-Bhagirathi (or Ganga) used to run along the side of the Kalighat temple, Baruipur, Jaynagar, Chhatrabhog and Hatiagarh. At that time, between Khiderpore and Sankrail no flow existed. Presently, the stream between Khiderpore and Sankrail became known as KatiGanga. A channel had been dug at the time of Alibardi Khan in the middle of the 18th century. This happened with the assistance of Dutch traders, who also set up a toll point on the Hooghly river. So the present reach of the Hooghly is the lower part of the historical Saraswati. Kolkata the capital of West Bengal is located on the banks of the Hoogly river. Tidal bore The tide runs rapidly on the Hooghly, and produces a remarkable example of the fluvial phenomenon known as a tidal bore. This consists of the head-wave of the advancing tide, hemmed in where the estuary narrows suddenly into the river, and often exceeds in height. It is felt as high up as Naihati 35 km upstream of Calcutta, and frequently destroys small boats. A tidal bore which overcame the banks of the river in 1876 was reported to have killed up to a hundred thousand people. The difference from the lowest point of low-water in the dry season to the highest point of high-water in the rains is reported to be . The greatest mean rise of tide, about , takes place in March, April or May - with a declining range during the rainy season to a mean of , and a minimum during freshets of . History In its upper reaches the river is generally known as the Bhāgirathi, until it reaches Hooghly. The word Bhāgirathi literally means "caused by Bhagiratha", a mythical Sagar Dynasty prince who was instrumental in bringing the river Ganges from the heavens on to the earth, in order to release his 60,000 grand-uncles from a curse of the saint Kapila. In 1974, the Farakka Barrage began diverting water