HUGLI, or Hooghly, the most westerly and commercially the most important channel by which the Ganges enters the Bay of Bengal. It takes its distinctive name near the town of Santipur, about 120 m. from the sea. The stream now known as the Hugli represents three western deltaic distributaries of the Ganges—viz. (1) the Bhagirathi, (2) the Jalangi and (3) part of the Matabhanga. The Bhagirathi and Jalangi unite at Nadia, above the point of their junction with the lower waters of the Matabhanga, which has taken the name of the Churni before the point of junction and thrown out new distributaries of its own. These three western distributaries are known as the Nadia rivers, and are important, not only as great highways for internal traffic, but also as the headwaters of the Hugli. Like other deltaic distributaries, they are subject to sudden changes in their channels, and to constant silting up. The supervising and keeping open of the Nadia rivers, therefore, forms one of the great tasks of fluvial engineering in Bengal. Proceeding south from Santipur, with a twist to the east, the Hugli river divides Nadia from Hugli district, until it touches the district of the Twenty-Four Parganas. It then proceeds almost due south to Calcutta, next twists to the south-west and finally turns south, entering the Bay of Bengal in 21° 41′ N., 88° E.
In the 40 miles of its course above Calcutta, the channels of the Hugli are under no supervision, and the result is that they have silted up and shifted to such an extent as to be no longer navigable for sea-going ships. Yet it was upon this upper section that all the famous ports of Bengal lay in olden times. From Calcutta to the sea (about 80 m.) the river is a record of engineering improvement and success. A minute supervision, with steady dredging and constant readjustment of buoys, now renders it a safe waterway to Calcutta for ships of the largest tonnage. Much attention has also been paid to the port of Calcutta (q.v.).
The tide runs rapidly on the Hugli, and produces a remarkable example of the fluvial phenomenon known as a “bore.” This consists of the head-wave of the advancing tide, hemmed in where the estuary narrows suddenly into the river, and often exceeds 7 ft. in height. It is felt as high up as Calcutta, and frequently destroys small boats. 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 20 ft. 10 in. The greatest mean rise of tide, about 16 ft., takes place in March, April or May—with a declining range during the rainy season to a mean of 10 ft., and a minimum during freshets of 3 ft. 6 in.