This document provides design data and computations for the construction of a barrage, including: 1. Design flood discharge is 8000 cumec with a downstream high flood level of 533.472m. 2. Computations of afflux for various discharges show the maximum water level remains above the full reservoir level of 525.3m. 3. Charts and tables show relationships between discharge, area, elevation and other parameters for design of the barrage spillway and sluices.

1. CONSTRUCTION OF BARRAGE
COMPUTATION OF AFFLUX
Design data :
1 Max. Flood Discharge 8000.00 cumec
2 D/S HFL 533.472 m 534.73
3 FRL 525.30 m
4 Average bed level of river 521.00 m
5 Crest level 523.20 m
6 Afflux or Difference MWL & HFL(d/s)= 0.12 m
7 Height of Gate(FRL_CL+.3)= 2.40 m
8 Looseness factor
a) Minimum Stable Waterway (Pw), by Lacey's formula 432.01 m
b) No of bays 50 working + 5spare
c) Pier width 2 m
d) Gate width 8 m
e) The water way computed as per the opening & piers: 548.00 M
f) Looseness factor 1.268
9 Spillway bays
a) No. of bays = 50 working + 5spare
b) Width of each bay 8 m
c) P/H= (height of crest above RBL/Head of water over crest)= 1.048
d) Width of piers 2.00 m
e) Overall waterway excluding spare gates 498 m
10 Total waterway of the barrage between abutments 548 m
11 Discharge equqtion for submerged weir is given by
=Q1+Q2
Where,
Cd1=Coefficient discharge for submerged flow
Cd2=coeff. of dischrage due to difference u/s & d/s water level
L=Effective length of water way(m)
H=Difference in upstream & down stream water levels
ha =Head due to velocity of approach
d= Depth of down stream water above crest level
   
a
d
a
a
d h
H
g
d
LC
h
h
H
g
LC
Q 









 2
2
3
2
2
2
3
2
3
1

2. Discharge through scouring sluices(IS 6531)
Discharge through scouring sluices is given by
Where cd = coefficient of discharge = varies as per chart below
Sill level 521.00 m
Height of sluice 1.5 m
L = width of Sluice Barrel. 1.5 m
H1= Difference between upstream water level - sluice sill level.
H2 = Difference between u/s water level - top of gate level.
n=No of sluices 3
Total Discharge nQ









 3
3
2
3
3
1
2
3
2
H
H
L
C
g
Q d

3. THE TABLE INDICATE THE MAXIMUM WATER LEVEL ON UPSTREAM CORREPONDING TO VARIOUS DISCHARGES
% OF Q 100% 90% 80% 70% 60% 50% 40% 30% 20% 10%
Q-design 8000.00 7200 6400 5600 4800 4000 3200 2400 1600 800
crest EL 523.20 523.20 523.20 523.20 523.20 523.20 523.20 523.20 523.20 523.20
FRL 525.30 525.30 525.30 525.30 525.30 525.30 525.30 525.30 525.30 525.30
d/s HFL
533.47 533.08 532.61 532.14 531.06 530.27 529.17 528.20 527.15 525.66
L 498.00 498.00 498.00 498.00 498.00 498.00 498.00 498.00 498.00 498.00
U/S HFL 533.60 533.18 532.70 532.20 531.12 530.32 529.21 528.23 527.17 525.67
d 10.40 9.98 9.50 9.00 7.92 7.12 6.01 5.03 3.97 2.47
Area at MWL= 6892.91 6322.83 5795.46 5278.09 4359.77 3826.97 3155.17 2609.31 2035.11 1279.69
V 1.16 1.14 1.10 1.06 1.10 1.05 1.01 0.92 0.79 0.63
ha 0.07 0.07 0.06 0.06 0.06 0.06 0.05 0.04 0.03 0.02
H or afflux 0.12 0.10 0.08 0.07 0.06 0.05 0.039 0.03 0.02 0.01
Position of Afflux >FRL >FRL >FRL >FRL >FRL >FRL >FRL >FRL >FRL >FRL
HFL_d/s-CL 10.27 9.88 9.41 8.94 7.86 7.07 5.97 5.00 3.95 2.46
REVISED HFL(U/S) 533.60 533.18 532.70 532.20 531.12 530.32 529.21 528.23 527.17 525.67
Cd1 0.577 0.577 0.577 0.577 0.577 0.577 0.577 0.577 0.577 0.577
Cd2 0.800 0.800 0.800 0.800 0.800 0.800 0.800 0.800 0.800 0.800
Q1 56.18 44.35 34.61 25.84 21.68 16.44 13.28 9.33 5.43 2.88
Q2 7943.82 7155.65 6365.39 5574.16 4778.31 3983.56 3186.71 2390.67 1594.57 797.13
Q3 from sluiuice 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Q=Q1+Q2 8000.00 7200.00 6400.00 5600.00 4800.00 4000.00 3200.00 2400.00 1600.00 800.00

4. ΔQ 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

5. 0.00
522.50
523.00
523.50
524.00
524.50
525.00
525.50
526.00
526.50
527.00
527.50
528.00
528.50
529.00
529.50
530.00
530.50
531.00
531.50
532.00
532.50
533.00
533.50
534.00
534.50
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
6500
7000
7500
8000
8500
9000
9500
10000
ELEVATION(m)
DISCHARGE (cumec)
DISCHARGE VS AFFLUX
HFL+AFFLUX
FRL
Series8
CREST LEVEL
HFL (D/S)
HFL( U/S)
HFL( U/S)+AFFLUX
FRL
GATE OPEN CONDITION
CREST LEVEL

6. CHART-2
(H1-H2)/H1 C'
0.06 2.15
0.10 2.11
0.20 2.06
0.30 2.03
0.40 2.00
0.50 1.97
0.60 1.94
0.70 1.92
0.75 1.90
ht
H2
H1
1.90
1.95
2.00
2.05
2.10
2.15
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
H1
H1-H2
Relative gate opening
Discharge
Cofficient
C

7. TOTAL Q
Q=Q1+Q2+Q3
m m³/s
1.000 521.00 0.000 1.000
2.00 522.00 2.160 2.00
3.00 523.00 60.541 3.00
4.00 524.00 214.676 4.00
5.00 525.00 484.330 5.00
6.00 526.00 963.458 6.00
7.00 527.00 1490.616 7.00
8.00 528.00 2231.554 8.00
9.00 529.00 3093.678 9.00
10.00 530.00 3712.331 10.00
11.00 531.00 4763.991 11.00
12.00 532.00 5373.129 12.00
13.00 533.00 7048.167 13.00
14.00 534.00 9065.471 14.00
15.00 535.00 11489.406 15.00 450
16.00 536.00 14379.256 16.00 -1.08
17.00 537.00 17480.755 17.00
18.00 537.50 19031.505 18.00
INPUT ELEVATION 534.00 9065.47 14.00 15.00 534.00 535.00 9065.47 11489.41
535.00 11489.41 15.00 16.00 535.00 536.00 11489.41 14379.26
536.00 14379.26 16.00 17.00 536.00 537.00 14379.26 17480.76
537.00 17480.76 17.00 18.00 537.00 537.50 17480.76 19031.50
INPUT DISCHARGE 8000.00 533.47 13.00 14.00 533.00 534.00 7048.17 9065.47
7200.00 533.08 13.00 14.00 533.00 534.00 7048.17 9065.47
6400.00 532.61 12.00 13.00 532.00 533.00 5373.13 7048.17
5600.00 532.14 12.00 13.00 532.00 533.00 5373.13 7048.17
4800.00 531.06 11.00 12.00 531.00 532.00 4763.99 5373.13
4000.00 530.27 10.00 11.00 530.00 531.00 3712.33 4763.99
3200.00 529.17 9.00 10.00 529.00 530.00 3093.68 3712.33
2400.00 528.20 8.00 9.00 528.00 529.00 2231.55 3093.68
1600.00 527.15 7.00 8.00 527.00 528.00 1490.62 2231.55
800.00 525.66 5.00 6.00 525.00 526.00 484.33 963.46
SL.NO. AREA IN SQ.KM SL.NO.
m SQ.KM
1.000 521 0 1.000
2.00 522 21 2.00
3.00 523 206 3.00
4.00 524 525 4.00
5.00 525 955 5.00
6.00 526 1448 6.00
7.00 527 1954 7.00
8.00 528 2501 8.00
9.00 529 3054 9.00
10.00 530 3645 10.00
11.00 531 4311 11.00
12.00 532 5131 12.00
13.00 533 6215 13.00
14.00 534 7652 14.00
15.00 535 9397 15.00
16.00 536 11449 16.00
17.00 537 13502 17.00
18.00 538 14528 18.00
INPUT ELEVATION 533.47 6892.91 13.00 14.00 533.00 534.00 6214.64 7652.16
533.08 6322.83 13.00 14.00 533.00 534.00 6214.64 7652.16
532.61 5795.46 12.00 13.00 532.00 533.00 5131.37 6214.64
532.14 5278.09 12.00 13.00 532.00 533.00 5131.37 6214.64
EL
SL.NO.
EL
SL.NO.

8. 531.06 4359.77 11.00 12.00 531.00 532.00 4311.29 5131.37
530.27 3826.97 10.00 11.00 530.00 531.00 3644.61 4311.29
529.17 3155.17 9.00 10.00 529.00 530.00 3053.60 3644.61
528.20 2609.31 8.00 9.00 528.00 529.00 2501.42 3053.60
527.15 2035.11 7.00 8.00 527.00 528.00 1954.35 2501.42
525.66 1279.69 5.00 6.00 525.00 526.00 954.87 1447.90
INPUT AREA 955.00 525.00 5.00 6.00 525.00 526.00 954.87 1447.90
956.00 525.00 5.00 6.00 525.00 526.00 954.87 1447.90
957.00 525.00 5.00 6.00 525.00 526.00 954.87 1447.90
958.00 525.01 5.00 6.00 525.00 526.00 954.87 1447.90
959.00 525.01 5.00 6.00 525.00 526.00 954.87 1447.90
960.00 525.01 5.00 6.00 525.00 526.00 954.87 1447.90
961.00 525.01 5.00 6.00 525.00 526.00 954.87 1447.90
962.00 525.01 5.00 6.00 525.00 526.00 954.87 1447.90