Sunday, May 26, 2013

Bay of Bengal - A pristine water resource

Ian Morris, in “Why the West Rules – For Now” predicts that South India is likely to face serious water shortages by 2025. It is not too wrong to say the shortage has already arrived in 2013 itself – starting with Tamil Nadu. Three suggestions to improve availability of potable water in India.

View of Bay of Bengal from Chennai

[1] Make Bay of Bengal a fresh water storage body:

The Bay of Bengal is the largest bay in the world. This bay occupies an area of 2,172,000 KM². A number of large rivers – the Ganges, Brahmaputra, Godavari, Mahanadi, Krishna and Kaveri flow into the Bay of Bengal. It is estimated that the annual run from the rivers into the bay is about 8,000 KM3. The average depth of the bay is 2.5 KM. Then, the total volume of water is around 2172000 x 2.5 = 5,430,000 KM3. If there is no salt water incursion into the bay, it would be the largest fresh water bay in the world as well.

A few studies have revealed that a saline 'pump' near Sri Lanka adds saltiness to the water by circulating waters from the Arabian Sea into the bay. If the 'pump' is managed, then in due course, the bay will turn into a natural fresh water resource.

As such, the salinity peaks 50m below the surface. Even if 10m of the fresh water floating on the bay surface is utilizable, 217200 KM3 of fresh water would be available. It is the fresh water floating on the bay that promotes the monsoons. Salinity in the bay should be carefully measured and monitored to convert the bay into a pristine water resource.

[2] Pipe river water from North to South:

Since there is very sizable runoff into the bay, it would do no harm to distribute water from the Ganges, Brahmaputra, Godavari, Mahanadi and Krishna to the South. I doubt it is practical to “network” and “link” the rivers in any fashion. The only practical approach may be to carry water in closed pipe lines like the Veeranam line supplying 180 million litres of water daily to Chennai. The pumping lines could be laid parallel to railway tracks for easy construction, networking and maintenance.

Chennai Metrowater sells per load of 10M3 of water at Rs. 670/- A load of divine Ganges water drawn straight from Haridwar might fetch premium prices in the south.

[3] Prevent Pollution:

This is easier said than done.  Pollutants are often let into water bodies, as there is no other drain into which it could be let into. An extensive drainage system should be built so that the pollutants can be streamed into it, processed and recycled. The drainage stream ought not to be allowed to run into rivers, canals, bay or the oceans.

The shortest river that empties into the bay, is River Cooum – about 64 KM long with its estuary near the Chennai harbour.  Until 1960s, this was a fresh water river. This river is now virtually used as a drain. No river should be used to drain wastes. The real test to check if pollution control measures are working correctly is to find potable water in the Cooum.


[1] 'Why the West Rules – For Now', Ian Morris
[7] In re Networking of Rivers,