Model Question Paper 1
Time -3 hours
CE-4002 Hydraulic Engineering and water resources
1. (a) What is meant by Irrigation? Describe five Irrigation methods.
(b) Draw the Hydrological cycle giving main process of it. Briefly explain the importance of
Hydrological cycle.
2. (a) Write short notes on the following terms in irrigation
i.
Field Capacity FC
ii.
Wilting Point WP
iii.
Total available water TAW
iv.
Irrigation Interval
v.
Root depth
(b) If rooting depth of Potatoes in April is 0.5m and FC= 32% , WP=17% and evaporation is
5mm/dayWhat should be the irrigation interval? (Density of soil-1.3g/cc)
3. What are the methods of measuring discharge (Q) of a river? The following readings were taken
using current meter. The velocity is given as ,
n> 0 .33 rev/s ; v = 0.2667n + 0.008 (m/s)
n ≤ 0.33 rev/s ; v = 0.2512n + 0.013 (m/s)
Distance
from one end
(m)
0.30
0.60
0.90
1.20
1.50
1.80
2.10
2.40
2.70
3.00
Width of
strip (m)
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
Find velocity and Discharge.
0.30
0.30
ddDDddddddd
Water depth d at
middle of the strip
from free surface (m)
0.17
0.17
0.18
0.17
0.19
0.20
0.16
0.15
0.15
0.11
Time taken for
50 rev at 0.2d
(s)
62.1
39.8
36.1
30.0
33.7
27.5
24.0
42.0
36.0
71.9
Time taken for
50 rev at 0.8d
(s)
67.1
38.5
38.9
30.7
32.8
27.2
29.0
43.0
36.0
71.9
4. Describe the method of measuring of infiltration.
An infiltrometer is used to determine the infiltration capacity of a clayey soil. The experiment lasted
120 minutes. During the experiment water was added to maintain a constant water level in the ring.
The total volume of water added is tabulated below. The area of the ring is 600cm2.
Time (min)
0
1
3
5
10
20
40
60
90
120
Volume added (cm3)
0
60
162
252
427
657
837
957
1122
1272
a. Compute for each time interval the infiltration capacity in cm/hr
b. Plot the infiltration capacity (cm/hr) verses time (min)
c. Estimate the ultimate value of the infiltration capacity.
5. What is Hydraulic jump? Describe the initial depth and the sequent depth.
What is the sequent depth y2and length of the hydraulic jump where V=8.5m2/s, initial depth is y1 =
0.50 m (length of the jump L = K* (y2-y1) where K is coefficient = 1to1.5)
6. In a rectangular area three rain gauges. A, B and C located as shown in the figure below. The
recorded rain fall for June is as follows:
Rain gauge station
Rainfall (mm)
A
75
B
40
C
30
Compute the rainfall depth in mm using a. The arithmetic mean method
b. Thiessen polygon method
A
B
C
7. The discharge in a small concrete lined irrigation canal is to be determined with the tracer method.
(Salt dilution method) for this purpose kitchen salt is used with a concentration of 130g/l. The tracer
is injected in the canal at A with a constant rate of .10 l/s. At point B50 m downstream where
complete mixing occurs, the original electrical conductivity EC of the river water of 360 µS/cm
increases to a maximum 400 µS/cm during the experiment.
a. Compute the discharge in m3/s given that EC = 1 µS/cm correspond to approximately 640 µg/l
TDS (Total Dissolved Salts)
b. Use the manning equation to estimate the discharge in the same concrete lined canal, given a
bottom width of 30 cm side slopes 4: 3 a constant water depth of 40 cm and a difference in
bottom elevation between A and B of 35 cm. the distant between AB is 50 m.
8. Given below is a 12 hour unit hydrograph. Construct the 12-hr S curve by plotting the summation of
the given 12-hr ordinates, and derive both instantaneous 6-hr unit hydrograph.
Time
hr
Flow
m3/s
0
12
24
36
48
60
72
84
96
108
120
0
103
279
165
78
36
20
11
5
3
0
9. Describe the ø index and W index.
Derive ø index for the following data.
Time
Rain fall (cm)
00.00 – 01.00
01.00 – 02.00
02.00 - 03.00
03.00 – 04.00
04.00 – 05.00
05.00 – 06.00
06.00 – 07.00
1.50
0.70
0.80
0.85
0
0.20
0.30
Run off m3/s
10.40
41.70
85.20
144.60
189.50
159.70
66.30
10. Determine the 2-h unit hydrograph from the given 4-h unit hydrograph
0
2
4
6
8
10
12
14
0 8 20 43 80 110 130 146
38
40
42
44
10
5
2
0
Eng. Nelson P. Jayatilaka
16
18
20
22
150 142 130 112
24
26
28
32
34
36
90
70
52 38 27
30
20
15