Water Resource Engineering
Exam Duration: 45 Mins Total Questions : 30
A agricultural land of 437 ha is to irrigated for a particular crop. The base period of the crop is 90 days and the total depth of water required by the crop is 105 cm, if rainfall of 15 cm occurs during the base period, the duty of irrigation water is
- (a)
437 ha/cumec
- (b)
486 ha/cumec
- (c)
741 ha/cumec
- (d)
864 ha/cumec
An outlet irrigates an area of 20 ha. The discharge (litre/s) required at outlet to meet the evapotranspiration requirement of 20 mm occurring uniformly in 20 days neglecting the other field losses is
- (a)
2.52
- (b)
2.31
- (c)
2.01
- (d)
1.52
With the increase in supplied irrigation water, the yield of crops
- (a)
increase continuously
- (b)
decrease continuously
- (c)
Increase upto a certain limit and then becomes constant
- (d)
Increase upto a certain limit and then decrease
A canal was designed to supply the irrigation needs of 1000 ha of land growing rice of 140 days base period and having a delta of 130 cm. If the canal water is used to irrigate wheat of base period 119 days and having a delta of 50 cm. The area that can be irrigated is
- (a)
452 ha
- (b)
904 ha
- (c)
1105 ha
- (d)
2210 ha
What is the regime scour depth for a channel in soil with slit factor of unity and carrying 8 m3/s/m of discharge intensity in accordance with Lacey's regime theory?
- (a)
3.6 m
- (b)
4.2 m
- (c)
5.4 m
- (d)
25.6 m
A crop X is grown black soil with available soil water of 150 mm/ha depth of soil. Given that the rooting depth is 2.5 m, the fraction of available soil water is 0.80 and the application efficiency is 0.85, then the required depth of irrigation applicable will be equal to
- (a)
150 mm
- (b)
250 mm
- (c)
353 mm
- (d)
240 mm
Lacey's scour depth for a stream carrying a discharge of 3 cumec/m width and having a slit factor 1.2 is
- (a)
1.32 m
- (b)
2.64 m
- (c)
3.96 m
- (d)
4.32 m
An irritation canal proposed to be excavated in an incoherent alluvium of medium size 0.4 mm for carrying a discharge 40 cumec, should ideally have a bed slope of
- (a)
1 in 6000
- (b)
1 in 52000
- (c)
1 in 2000
- (d)
1 in 1265
The slit factor used by Lacey in his regime theory was equal to for upper Bari-doab alluvium.What was the median size of this alluvium?
- (a)
0.28 mm
- (b)
0.32 mm
- (c)
0.40 mm
- (d)
0.5 cm
The optimum Kor water depth for a Kharif crop is 19 cm with an allowed Kor water period of 3 weeks, the outlet discharge factor for this crop will be
- (a)
955 ha/cumec
- (b)
782 ha/cumec
- (c)
860 ha/cumec
- (d)
680 ha/cumec
If the discharge required for different crops grown in a field is 0.4 cumec and the capacity factor and time factor are 0.8 and 0.5 then design discharge for the distributary will be
- (a)
0.80 cumec
- (b)
0.16 cumec
- (c)
1.00 cumec
- (d)
1.24 cumec
An irrigation canal is to be designed to delivery 6.25 cumec to meet the peak Rabi demand of a total of 5100 ha of cropped area. The estimated canal losses are 25% of the head discharge. The duty on capacity of this small canal will be
- (a)
816 ha/cumec
- (b)
1020 ha/cumec
- (c)
653 ha/cumec
- (d)
612 ha/cumec
The 8000 ha of gross commanded area of an irrigation project includes 20% of reserved forests, user lands roads etc. The pastures and fallow lands are 10% if the intensity of irrigation is 50%. The area to be irrigated is
- (a)
4000 ha
- (b)
3200 ha
- (c)
2800 ha
- (d)
2600 ha
The total irrigation depth of water, required by a certain crop in its entire growing period of 150 days is 25.92 cm. The culturable command area for a distributory channel is 10000 ha. The distributory channel shall be designed for a discharge
- (a)
2 cumecs
- (b)
less than 2 cumec
- (c)
20 cumec
- (d)
more than 20 cumec
A standard triangular lined canal section with 1.5 H : IV side slopes has a capacity of 26 cumec and full supply depth of 2.5 m. The lining material for the channel would be safe for withstanding mean velocity of
- (a)
1.8 m/s
- (b)
2.0 m/s
- (c)
2.2 m/s
- (d)
2.4 m/s
While designing a hydraulic structure, the piezometric head at the bottom of the floor is computed as 10 m. The datum is 3 m below floor buttom. The assumed standing water depth above the floor is 2 m. The specific gravity of the floor material is 2.5. The floor thickness should be
- (a)
2.00 m
- (b)
3.33 m
- (c)
4.40 m
- (d)
6.00 m
The critical exit gradient suggested in Khosla's theory of design of weirs and barrages is
- (a)
less for more porous soil
- (b)
more for more porous soil
- (c)
equal for all kind of soil
- (d)
None of the above
The horizontal destabilizing caused by formation of waves in a storage reservoir having a fetch of 40 km, due to high wind of 160 km/h is about
- (a)
30 kN
- (b)
60 kN
- (c)
90 kN
- (d)
130 kN
The base width of an elementary profile of a gravity dam of height H is b. The specific gravity of the material of the dam is G and uplift pressure coefficient is K. The correct relationship for no tension at the heel is given by
- (a)
\(\frac { b }{ H } =\frac { 1 }{ \sqrt { G-K } } \)
- (b)
\(\frac { b }{ H } =\sqrt { G-K } \)
- (c)
\(\frac { b }{ H } =\frac { 1 }{ G-K } \)
- (d)
\(\frac { b }{ H } =\frac { 1 }{ K\sqrt { G-K } } \)
Wheat crop requires 55 cm of water during 120 days of base period. The total rainfall during this period is 100 mm. Assume the irrigation efficiency to be 60%. The area (in ha) of the land which can be irrigated with a canal flow of 0.01 m3/s is
- (a)
13.82
- (b)
18.85
- (c)
23.04
- (d)
230.40
An agricultural land of 437 hectare is to be irrigated for a particular crop. The base period of the crop is 90 days and the total depth of water required by the crop is 105 cm, if a rainfall of 15 cm occurs during the base period, the duty of irrigation water is
- (a)
437 ha/cumec
- (b)
486 ha/cumec
- (c)
741 ha/cumec
- (d)
864 ha/cumec
An outlet irrigates an area of 20 ha. The discharge (L/S) required at this outlet to meet che evapotranspiration requirement of 20 mm occuring uniformly in 20 days neglecting other field losses is
- (a)
2.52
- (b)
2.31
- (c)
2.01
- (d)
1.52
The culturable command area for a distributory is 2 x 108 m2. The intensity of irrigation for a crop is 40%. If Kor water depth and Kor period for the crop are 14 em and 4 weeks respectively, the peak demand discharge is
- (a)
2.63 m3/s
- (b)
4.63 m3/s
- (c)
8.58 m3/s
- (d)
11.58 m3/s
The depth of moisture in root zone at field capacity and permanent wilting point per meter width of soil are 0.5 m/m and 0.2 m/m respectively. Take dry weight of soil as 13.73 kN/m3
The field capacity will be
- (a)
30.72%
- (b)
35.72%
- (c)
69.97%
- (d)
100%
The border strip method of irrigation 0.04 ha area is irrigated from tubewell with a discharge of 0.02 cumec. The infiltration capacity of soil may be taken as 5 cm/h and the average depth of flow on the field as 10 cm.
The time required to irrigate a strip of land of area 0.04 ha will be
- (a)
39.06 min
- (b)
43.06 min
- (c)
11.05 min
- (d)
65.6 min
The border strip method of irrigation 0.04 ha area is irrigated from tubewell with a discharge of 0.02 cumec. The infiltration capacity of soil may be taken as 5 cm/h and the average depth of flow on the field as 10 cm.
The maximum area that can be irrigated from this
- (a)
144 m2
- (b)
360 m2
- (c)
1440 m2
- (d)
3600 m2
A certain crop is grown in an area of 1000 ha which is fed by a canal system. The data pertaining to irrigation are as follows
Field capacity of soil =18%
Optimum moisture =10%
Permanent wilting point =8%
Effective depth of root zone =60 cm
Relative density of soil =1.3
If frequency of irrigation is 5 days and the irrigation efficiency is 20%, the daily consumptive use will be
- (a)
7.8 cm
- (b)
0.78 cm
- (c)
6.24 cm
- (d)
1.248 cm
A certain crop is grown in an area of 1000 ha which is fed by a canal system. The data pertaining to irrigation are as follows
Field capacity of soil =18%
Optimum moisture =10%
Permanent wilting point =8%
Effective depth of root zone =60 cm
Relative density of soil =1.3
What will be water discharge in m3/s required in the canal feeding the area?
- (a)
14.44 cumec
- (b)
1.44 cumec
- (c)
6.24 cumec
- (d)
7.22 cumec
A soil field capacity of 30% and wilting coefficient (Permanent wilting point) of 15%. They dry weight of soil is 1.5 g/cc. The root zone depth is 50 cm.
If the water application efficiency is 65%, what will be water requirement to be applied in field?
- (a)
5.85 cm
- (b)
13.17 cm
- (c)
13.85 cm
- (d)
30.77 cm
The following parameters relate to the design of weirs of permeable foundations
1. Scour depth
2. Exit gradient
3. Uplift pressure
4. Unbalanced head
Design of the downstream and pie of the wier depends upon
- (a)
1 and 2
- (b)
1 and 4
- (c)
2 and 3
- (d)
3 and 4
1654060945.png)
1654060942.png)
1653987551.png)
1653987086.png)
1582095229.jpg)
