Calcutta, Sept. 6: The Union shipping ministry has directed the Calcutta Port Trust (CPT) to open a new shipping channel to cut dredging costs and improve the navigability of the Haldia port from September 15.

The long-pending move can potentially reduce the cost of shipping at the port and add 4 million tonnes of cargo every year.

The new Eden channel will bypass the existing longer route ships take to come to Haldia (see map). Also known as the western channel, Eden is a deeper drafted channel than the existing Auckland route and may enable ships to carry 4,000 tonnes more per trip.

Moreover, Eden may not require extensive dredging to keep the route navigable like Auckland. The CPT spends around Rs 400 crore annually to keep the riverine port, the lifeline of Bengal's economy, alive.

"The ministry has told us to operationalise the Eden channel from September 15 and we will do so. This is mainly being done to reduce the cost of dredging, bulk of which is provided by the Centre," R. P. S. Kahlon, chairman of the CPT, said.

Last fiscal, the CPT spent Rs 120 crore on dredging from internal generation, while Rs 280 crore came from the Centre. By shifting to the Eden channel and using a new dredging method, the annual cost may come down to Rs 150-200 crore, according to a study by Boston Consulting Group.

More cargo capacity

The Eden channel can offer about one metre more depth - the difference between the riverbed and the water level during low tide - than the Auckland channel, which runs closer to Sagar Island. However, ships usually wait for the high tide, which adds 3.5-4 metres to the water level in the Hooghly to navigate.

According to shipping experts, every metre of additional draft - depth plus tidal rise - can allow ships to carry 4,000 tonnes of additional cargo. A back-of-the-hand calculation shows Haldia can get 4 million tonnes cargo given that it handles around 1,000 ships a year.

This in turn can reduce the cost of transport as shipping lines can bring in more cargo per trip.

Usually, ships carry 18,000-19,000-tonne cargo parcel to Haldia after discharging at Visakhapatnam, Paradip or Dhamra. With the Eden channel being on the western side of the river, the distance from these ports to Haldia will be 17-20 nautical miles less than Auckland.

New desilting method

The CPT may now opt for barge loading of dredged silt and dump it on the shore. At present, dredgers spend 70 per cent of their working time sailing to the main dumping site from the dredging site.

In the new method, the dredger will remain at the site, while the barges will take the sediment to the dumping site. This trend is now catching up with international dredging companies who are investing in barge loaders.

The new method will ensure that the dredgers spend more time desilting the riverbed. Hence, lesser number of dredgers can do the work, saving money for the CPT as well as the government.

At present, 75 per cent of the dredging cost are spent to clear the Auckland channel and the rest for the Jellingham channel. Ships entering the Hooghly take the Auckland channel initially before those heading for Haldia switch to Jellingham.

BCG has estimated that around Rs 110 crore may be annually spent for dredging in the Eden channel and another Rs 30-90 crore for maintaining the lower part of the Auckland channel used by the Calcutta-bound ships.

Challenges remain

The Eden channel has been in the making for nearly 7-8 years now, but the CPT did not push the use of this route much. Pilots navigating the treacherous waterways when they enter the Hooghly from the Bay of Bengal were reluctant to try the route. Kahlon said a meeting with pilots had been held and they had agreed to move the ships through Eden.

Moreover, the CPT has commissioned the Central Water Research and Power Research Station (CWRPRS) for a study on the stability of the Eden channel.

"We do not know the hydrology of the route well and whether it is stable. We are not absolutely certain whether any dredging will be required to maintain it. The CWRPRS study will throw light on that," a port official said.