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controlled, the freshet period can be prolonged and sudden freshet peaks which
cause heavy sand movement and bank erosion will be flattened;
The upper five bars and crossings at Panchpara, Sankrail, Munikhali, Pir Sareng,
and Pujali will improve;
The lower four bars at Eastern Gut, Moyapur, Roypur and Ninan will also
improve with the construction of training works;
With upland discharge and training works and/or dredging at some of the bars,
there will be no additional difficulties at the bars and crossings. The measures
adopted on the Ganga-Bhagirathi-Hooghly systems will not have any ill effects
on the estuary below Diamond Harbour;
The tidal reach will improve and the frequency and intensity of bores will
decrease;
Salinity in water supplied to Kolkata and industrial areas will diminish;
The drainage capacity of the Bhagirathi and upper Hooghly will improve and
flood hazards in the catchment areas will be reduced as well as sanitation and
public health will ameliorate.
Minimum Upland Discharge
Based on the data given to him on hydraulics and hydrology of the Hooghly,
Dr. Hensen suggested a sequence of upland discharge as under:
(i) January-April: 40,000-20,000 cusecs,
(ii) First Half of May: Up to 20,000 cusecs,
(iii) 15th May to 20th June: Up to 40,000 cusecs,
(iv) 20th June to 30th June: 40,000-60,000 cusecs,
(v) July-September: 60,000-140,000-80,000 cusecs, and
(vi) October-December: 80,000-40,000 cusecs.
He added that the model experiments will also have to determine the duration
and quantity of the upland discharge that could be regulated to the best advantage.
Regarding insufficient collection of data, Dr. Hensen observed:
In spite of exhaustive information which is available about the hydraulic, morphological
and historical characteristics, it is not sufficient to determine with certainty all the details of
the development of the Hooghly. For this, the period of intensive measurements which have
to be taken in Nature, is too small. Only by carrying out these observations in a systematic
way, one can obtain definite information about the Hooghly and the Bhagirathi. The work
should consist of observations in Nature, their evaluation and theoretical analysis in the
office and model experiments.
In 1962, Calcutta Port had set up a specialized Hydraulic Study Department to
assess requirement of water, the morphological changes, collection and storage of
data, physical and mathematical model studies and to advise various training mea-
sures and dredging. It also assessed water requirement from the Farakka Barrage for
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