Dredging: Kolkata Port to carry out hydrological survey in Hooghly Estuary

Kolkata: In a bid to ensure smooth passage of vessels, Syama Prasad Mookerjee Port, Kolkata, will conduct a hydrological survey before executing dredging in the Hooghly Estuary, primarily in the shipping channel leading to Haldia Dock Complex (HDC).

It was learnt that the Kolkata Port authorities will open the bidding process this month to engage a contractor for the work through a tender. According to the port authorities, the two dock systems, one at Kolkata and the other at Haldia, on the Hooghly estuary, are located 144 km and 44 km inland respectively, from Sagar Island at the mouth of the estuary debouching into the Bay of Bengal. The estuary is “alluvial “and perennially “well mixed”. The entire navigational channel from Eden to Haldia anchorage is interspersed with shallow stretches.

Proceeding downstream from Kolkata, the estuary becomes braided around a central island – the Nayachara Island opposite Haldia Dock – downstream of Diamond Harbour at about 100 km from Kolkata. The estuary becomes broader and fans out into principally two channels: On the east along Diamond Harbour, Kantabaria-Kulpi-SilverTree – Bedford -Sagar Island, and on the west along Diamond Harbour, Balari -Haldia-Jellingham-Auckland-Eden. Port authorities said that soil data of Haldia Anchorage, Jellingham and Lower Jellingham Crossing, and Upper and Lower Eden Bar and Haldia Reach, indicates fresh deposition of sediment comprising a mixture of sand, silt and clay.

“On an average 15 vessels (inward and outwards) pass through the shipping channel per day. The port is maintaining the depths in the channel by regular dredging through Trailing Suction Hopper Dredgers (TSHD),” said an official.

It was learnt that before commencement of dredging, a joint hydrographic survey with the contractor shall be undertaken to ascertain the depths in various localities in the dredging areas. Thereafter, similar joint surveys will be carried out once in every neap tide which will occur twice in each month.

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