Table 1: The structural dimensions of barrage and rehabilitation scenarios. Description Barrage Subsidiary weir Stone at stable slope Two step stilling basin At 800ft At 600ft U/S floor (ft) Concrete 20 40 40 Stone apron at the slope of 1:15 up to anticipated retroregression level (EL662) for a length of 140 21.5 Block 11 20 20 12.5 Stone Apron 25 25 25 26 Sloping portion 61 69 62.75 D/S floor (ft) Concrete 70 95 95 69.75 Block 60.58 43.5 43.5 41 Stone apron 40 45 45 40 Sheet pile 1 3 3 2 Width across river 3353 3913 3913 2520 Divide wall (ft) About 800 Mechanical gates 54 in front of left undersluices Navigation Bay 1 1 1 Fish ladder 2 2 2 Sluice way (ft) 495 495 495 Guide banks (ft) about 1200 about 800 Pressure pipes yes yes yes yes Cofferdam yes yes can be avoided yes