Geoscience Reference
In-Depth Information
Tables 10.18 and 10.19 show that the number of ships and the volume of cargo
carried by the two docks varied between 1960 and 1989, owing mainly to non-
availability of sufficient upland discharge, causing siltation of the river-bed and to
the global tendency to switch over to bigger and deep-draught vessels. The tables
also show that the Haldia dock became very active after adoption of regulatory
measures.
As stated, river regulatory measures have been partly put into effect below
Diamond Harbour. The 2.8 km long northern guide-wall above Nayachar was com-
pleted in 1991-1992 to isolate the two distinct navigation channels on either side
of the island and to stop inter-mixing of the tidal flow into them and prevent exces-
sive siltation in Haldia port area. Dredging of the Jiggerkhali Fiat has also been
done; but, the effect of the guide-wall was not felt and siltation in the channel
continued. The flat has been extended inside the channel, blocking the channel
completely. Thus, instead of giving any benefit, the northern guide-wall adversely
affected the channel by creating a cul-de-sac and a slack zone in the Flat region.
The alluvial and moving silt-load and the river-bed materials added with unpre-
dicted geo-morphological changes in the estuary have aggravated the problem.
Vessels bound for Calcutta Port are now plying on the eastern channel on the other
side - the Rangafalla; those bound for Haldia port only use the western Haldia
channel; this led to gradual improvement of the draft in Calcutta and Haldia port
complexes, as shown in Table 10.20.
The table shows that the substantial improvement that has taken place in both
Haldia and Calcutta ports has been due to fluctuations in upland discharges. Haldia
port improved probably because of fluctuations in annual dredging in the estuary
region.
Table 10.20 Draft available in Calcutta and Haldia port area
Calcutta port
Haldia port
Above 7.0 m
(in days)
Above 7.50 m
(in days)
Above 8.0 m
(in days)
Above 8.50 m
(in days)
Year
1
2
3
4
5
1960-1961
45
18
-
1964-1965
60
35
-
1972-1973
95
70
-
1981-1982
154
69
360
320
1984-1985
105
33
125
26
1988-1989
220
115
305
150
1992-1993
255
143
341
233
1994-1995
297
175
242
102
1995-1996
236
128
236
70
1996-1997
191
72
187
44
1997-1998
233
114
125
16
1998-1999
232
142
258
114
1999-2000
205
120
292
178
 
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