Inconsistency, or A Conspiracy? - The Ganga: Water Use in the Indian Subcontinent - page 105

Dr. J. J. Dronkers, an expert on tidal hydraulics in Netherlands, who was also
consulted by Calcutta Port Commissioners in 1968 recommended minimum 41,000
cusecs to push accumulated sand downward, which could otherwise move upward
for a mean tide range of 14 feet. For the maximum tidal range of 18-20 feet, which
is normal near the port, the minimum requirement would be about 60,000 cusecs.
Many Indian experts also gave their views on the issue. Dr. D. V. Joglekar,
Director of the CWPRS said in his report of 1968 that a discharge of the order
of 46,000 cusecs would be necessary to restore the river to 1935-1936 condition,
but considering the availability of water at Farakka, at least 40,000 cusecs were
necessary.
A. C. Mitra, Chief Engineer of Uttar Pradesh Irrigation Department and
Chairman of the Technical Advisory Committee of the Farakka Barrage Project
held that a sustained head-water discharge of 40,000 cusecs was the minimum in
the non-freshet season to neutralize the landward drift of sediments throughout the
tidal portion of the river and to bring the regime back to 1930-1935 condition; how-
ever, this could be gradually reduced as per availability of water at Farakka after
achieving substantial improvement.
Other eminent engineers like Dr. K. L. Rao and Mr. Debesh Mukherjee also advo-
cated minimum head-water supply of 40,000 cusecs, round the year for rejuvenation
of the Hooghly. When the Barrage was nearing completion, Dr. Rao, then India's
Minister for Irrigation and Power, suddenly expressed doubts about the results of the
model tests in the feeder canal that a continuous flow of 40,000 cusecs was necessary
to save Calcutta port. He made a statement in Parliament on 3rd May 1973.

The results of the model tests by the Central Water & Power Research Station, Pune show
that the discharge given in the original report of 1959 is found to be satisfactory but the
model tests by the Calcutta Port Commissioners indicated the requirements of higher dis-
charges at 40,000 cusecs during the lean months. Due to the difficulties of simulation, model
tests, especially for large rivers, have serious limitations in giving any precise quantitative
answer to problems and can, at best, be indicative. It is difficult to quantify, precisely, at
this stage, as to what is the discharge required to meet the needs of Calcutta port. The exact
requirements of water are best determined by observation on prototype itself. It is, therefore,
decided to adopt the following procedure for operation of the Farakka project.

the Feeder Canal will carry the full discharge
of 40,000 cusecs throughout the year, including lean months;
b) The necessary discharge for efficient functioning of Calcutta port by continuing the
improvement as a consequence of (a) will be determined by a study team by observing
the effects during the first five years and subsequent two years, when the discharge will
be varied;
c) Simultaneously with the above, trench-dredging will be carried out above Howrah
Bridge in varying degrees, so that the aforesaid Study Team can observe its effects on
tidal prism and check any heavy movement of bed sediment on to the port area; and
d) After the period of seven years, the entire position will be reviewed in the light of reports
and observations of the aforesaid Study Team.

a) For five years, after water is let down ...

In conclusion, it may be stated that the Government of India fully recognize the importance
of maintaining the navigability of the Hooghly for the preservation of the Calcutta port as
one of the topmost Indian ports and will take all necessary steps to ensure the same.