James Rennell, an Englishman, prepared a Bengal Atlas, which was dedicated to Lord Clive in 1780. The map shows the Ganga flowing towards the East and then meandering towards Murshidabad district as Baugrutty (presently Bhagirathi) that was flowing southwards. The reasons for the Bhagirathi’s disconnection from the Ganga are unknown.
However, there was reportedly a surface-thin water flow from the Ganga to Bhagirathi even in the 1970s until it was finally blocked by the Jangipur barrage, constructed across the Bhagirathi, a few kilometers away from the Ganga, during the implementation of the Farakka Barrage Project (FBP).
The Farakka Barrage has been constructed across the Ganga, with more than 100 gates, to act as source of water to the Bhagirathi through a feeder canal to increase its flow and to sustain the ship-channels of KoPT. Interestingly, around 50 per cent of the barrage gates have been kept closed to ensure adequate an waterhead.
This has choked the mighty Ganga and has also resulted in erosion of the river bank in Malda district since the mid-1990s. KoPT was entrusted with the work of excavating and reforming the Bhagirathi to proper depth, width and slope to enable it to receive the increased supply from the Ganga.
Of late, the supply to the Bhagirathi has dwindled. This is evident from frequent shutdowns of the NMTC power station for scarcity of water, that is supplied to it through the canal. In addition the choked Ganga is emitting warning signals through the vibration of the barrage structure ~ the surrounding areas are vulnerable to devastation in the wake of a natural calamity.
It is time to reflect on the free flow of the mighty river by opening all the gates before a disaster strikes. The right course of action would be to reconnect the Bhagirathi with the Ganga directly to restore its natural water source as it existed before and shown in Rennell’s Bengal map of 1780.
As the Bhagirathi flows south and reaches the tidal sea water zone, it becomes the Hooghly river, fondly called Ganga as it passes through Kolkata. The source of water to the Hooghly is the flood tide from the Bay of Bengal twice a day through two estuary channels, one Haldia-Ballary alongside the East Midnapore bank and the other at Rangafalla alongside the South 24-Parganas bank.
The two meet at Diamond Harbour and become a massive water source for the Hooghly. Interestingly, as the tide returns to sea as ebb, it cleanses the flood deposits in the river bed and sustains the Hooghly river. Unfortunately, this natural process has become tops-turvy since the 1990s due to interference by politically powerful vested interests.
When the Haldia Dock System was opened in 1977, the draft in the ship channel was around 12 meters. A Rs 40-crore Comprehensive Scheme, based on the port’s indigenous low cost rural employment oriented river tested composite material technology, was sanctioned in 1982 to provide two guide walls, one 3 kilometers in length at the northern tip of Nayachar Island and the other 10 kilometers in length at the southern tip of the same island.
Work on the Northern Guide Wall was taken up first in 1983-84 and by 1985-86 about 70 per cent was completed and reported to the Central Technical Advisory Committee. Then came a surprising directive from the Shipping Ministry to use imported technology, based on non-biodegradable synthetic polypropylene cloth mats, in the remaining construction.
KoPT’s River Training engineers pointed out the technical impracticability of the proposition explaining that using these cloth mats on already laid composite cages, made of concrete, bricks and bamboos, would make these synthetic non-biodegradable materials vulnerable to drift by high estuary current into the nearby Ballary Channel to clog and silt it up and thus destroy the scheme.
They even suggested that it be used in the Southern Guide Wall, a project that was yet to be taken up and where virgin beds were available for laying the cloth mats. An enraged and adamant administration then transferred all the port engineers, inducted inexperienced engineers on deputation from the state’s Public Works Department and executed the rest of the work. As feared , a large part of these non-biodegradable synthetic materials were ultimately drifted by high estuary current into the nearby Ballary Channel to choke and silt it up.
This stopped the movement of ships since the 1990s. Regretfully, execution of the Rs 40-crore Comprehensive Scheme (1982) was swept under the carpet without any audit. Those responsible who ruined Haldia port and who closed the tidal water to the Hooghly are yet to be exposed and brought to book.
The source of water to the river Hoogly is mainly flood tide from the sea through the two channels, Rangafalla and Haldia-Ballary. Presently, because of the silting up of Ballary Channel, flood water comes to the Hooghly only through the Rangafalla Channel and a weak ebb on its return journey.
It is unable to carry away the “bed deposits” to the sea.
Consequently, shoals have emerged all along the river. The submerged chars are now exposed and visible up to the mid-river in low water, one at Dakshineswar and the other at Pujali, near Budge Budge. The development is a matter of deep concern as it signifies gradual drying and dying of the river.
Eventually Kolkata and the adjoining urban areas will be the worst hit in the matter of water supply from Palta, Garden Reach and other pumping stations if the river Hooghly dies. Furthermore, the city and suburbs will remain waterlogged throughout the monsoon for lack of drainage. The people will become vulnerable to health hazards.
A Bhagirathi-Hooghly Rejuvenation Body needs urgently to be constituted to plan and execute the following measures:
* Survey of the entire length of the river Bhagirathi-Hooghly to locate impediments and remove them by the shore-disposal method of dredging. KoPT river survey department might be of help.
* Opening up the clogged Ballary Channel by surface excavation and shore disposal method of dredging to restore tidal water supply to the Hooghly as it existed in the 1980s.
* Linking the river Bhagirathi directly to the Ganga to restore its natural water supply source, as shown in Rennell’s 1780 Bengal Atlas. This will also restore the flow of the Ganga to the Bhagirathi-Hooghly.
* Freeing the mighty Ganga by opening all the Farakka Barrage gates and pre-empt a catastrophe in the surrounding area in the event of a natural calamity.
It will be a tragedy for the people of Bengal if the government does not respond adequately to the warning signal emitted by Nature, and remains insensitive to the possibility of Kolkata and other areas suffering from scarcity of drinking water. It won’t be long before the problem becomes intractable.
The writer is an IITIan and former Senior River Training Engineer of Kolkata Port Trust.