RETURN PERIOD
RECURRENCE CALCULATE
PERIOD
PROBABILITY
DEFINITIONS
FLOOD CONCEPT OF FLOOD
ROUTING
ROUTING
FLOOD ROUTING CHANNEL
LEVEL POOL
METHOD ROUTING
ROUTING
(Muskingum
(Pul's method)
method)
A method for obtaining flow hydrograph at
a point downstream hydrograph using one
or more known from the point upstream.
In the design of a reservoir, hydrograph of
outflow from the reservoir may be required
to determine the potential of the discharge
outlet structure.
If the system is a channel, it is named
distribution channels or distribution of river
flow. If the system is a reservoir, then it is
called channeling savings or distribution
reservoir.
Muskinghum Method
Q j+1 = C1 Ij+1 + C2 Ij + C3 Q j
- - -
-
-
Example
Sungai Perak will be straightened to solve the
flood problem that often occur in the area
around the village of Tanjung Bidara and
Kampung Gajah. Table below shows the
hydrograph inflow. Given k= 0.70 hour and
x= 0.20. Assume the first outflow as 950 m3/m.
Use the Muskinghum Method.
Time (hour) Inflow (m3/s)
1 0
2 1000
3 2000
4 4200
5 5200
6 4400
7 3200
8 2500
9 1500
10 1000
11 700
12 400
13 0
Solution
K = 0.7 hr
X = 0.20
t = 1 hour
C1 = t 2 Kx
C3 = 2K (1-X) - t
2K (1-X) + t
2K (1-X) + t
= 1 2 (0.7) (0.20)
2(0.7) (1-0.20) + 1 = 2(0.7) (1-0.20) - 1
= 0.3396 2(0.7) (1-0.20) + 1
C2 = t + 2 Kx = 0.0566
2K (1-X) + t Check = C1 + C2 +C3
= 1 + 2 (0.7) (0.20)
= 0.3396 + 0.6038 + 0.0566
2(0.7) (1-0.20) + 1
=1
= 0.6038
Time Inflow C1= 0.3396 C2= 0.6038 C 3= 0.0566 Outflow , Q
(hour) (m3/s) (m3/s)
1 0 - - - 950
2 1000 339 0 53.77 393.37
3 2000 679.2 603.8 22.26 1305.27
4 4200 1207.6 73.88 2707.80
5 5200
6 4400
7 3200
8 2500
9 1500
10 1000
11 700
12 400
13 0
Example
By using Muskingham method, calculate outflow
hydrograph. Given X = 0.25 and K = 9 hour.
Assume initial outflow is 110 m3/s. Estimate the
maximum outflow and the time it occurred
3
Time (hour) Inflow (m /s)
0 120
5 300
10 720
15 560
20 370
25 250
30 220
35 190
40 170
Table below show the inflow hydrograph. By
using Muskingham method, calculate outflow.
Given X = 0.3 and K = 3/8 day. Assume initial
outflow is 6 m3/s. Estimate the maximum
outflow and the time it occurred.
Time ( hour) Inflow (m3/s)
0 6
3 5
6 17
9 48
12 81
15 102
18 105
21 103
24 95
27 64
30 45
33 34
36 27
39 20
42 16
45 13
48 12
