Only a Barrage Can Save! - The Ganga: Water Use in the Indian Subcontinent - page 96

109-101

BAY NOS 100-78 BAY NOS 77-53 BAY NOS 52-13 NO

12-4

NO
3-1

SEASON 1967-68

SEASON 1965-66

SEASON 1967-68

SEASON 1966-67

SEASON 1968-69

WORK FOR SEASON 1965-66

WORK FOR SEASON 1966-67

WORK FOR SEASON 1967-68

WORK FOR SEASON 1968-69

Fig. 7.2 Coffer dam enclosures of Farakka Barrage for different seasons (See also Plate 9 on
page 371 in the Colour Plate Section)

The enclosure of a portion of river by coffer dam, completion of excavation,
dewatering, sheet piling, foundations and other permanent works and also the
removal of coffer dam prior to each flood season to allow flood water to pass
through the original river course, all had to be done within the limited period of
working season. Suggestion of cellular type coffer dam by foreign experts for clo-
sure of the river during construction was tried on an experiment basis, but the same
proved unsuccessful after passing of one flood season over it. The method was there-
fore abandoned. The construction of earthen coffer dam and its maintenance during
construction of the main structure was one of the most difficult works (Fig. 7.2).
However, with great dedication by a team of expert engineers and workers, the work
of construction of coffer dam was done for the 3-4 working seasons and the main
barrage structure could be completed in time in early 1970. Photographs 7.4 and
7.5 show sheet piling works in progress and well sinking on right bank of Farakka
respectively.
The construction of central bays of the barrage raft between 53rd and 77th bay
posed some difficulty. The crest of the bays was constructed in two stages. In the first
stage, the crest was kept lowered to allow the discharge to pass through the bays.
They were raised to the design level in the second stage after flood discharges passed
through the side-bays (Fig. 7.3). Photograph 7.6 shows Farakka Barrage piers under
construction in 1969.
The excavation and construction of Feeder Canal, one of the biggest of the world,
posed a number of problems. Experienced contractor with sufficient number of
workers was difficult to find. Heavy earthmoving machineries were deployed to
achieve progress satisfactorily. The rail-line and State and National Highway had