Kolkata: The first of its kind bathymetric survey of the 72-acre wide Rabindra Sarobar water body has recommended ‘succession cutter dredging’ at eight odd points where the deposition of sediment is maximum.
The study undertaken by a team from Jadavpur University’s School of Water Resource Engineering has pinpointed the specific locations for localised dredging through
cutter suction dredger that uses a rotating cutter head to dislodge the sediment, which is then sucked through a pipe and discharged.
“We have submitted the recommendations to the National Green Tribunal (NGT) and will act as per their directions. Currently, the use of any machinery that causes pollution is prohibited in the Lake’s water,” said a senior official of Kolkata Metropolitan Development Authority (KMDA), the custodian of the waterbody.
Dredging of the entire waterbody would have been a better option but that would have disturbed the entire ecosystem, so localised dredging can be an option.
The majority of the areas earmarked for dredging are in the Dhakuria side of the Lake.
The KMDA official said that initially JU had done the study on the basis of data of three years but after our request they increased their study period to 20 years database for a more comprehensive outcome.
Bathymetric survey maps the depths and shapes of underwater terrain to illustrate the land that lies below. Ultra sonographic ray is sent into the water and the depth is ascertained on the basis of the time this ray returns back.
The survey was held in the month of May, under the leadership Asis Majumdar, Professor , School of Water Resource Engineering.