Civil Engineering - 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
The plan area of a reservoir is 1 km2. They water level in the reservoir is observed to decline by 20 cm in a certain period, the reservoir receives a surface inflow of 10 ha-m and 20 ha-m are abstracted from the reservoir for irrigation and power. The pan evaporation and rainfall recorded during the same period at a nearby metrological station are 12 cm and 3 cm respectively. The calibrated pan factor is 0.7. The seepage loss from the reservoir during this period in hectare-m is
- (a)
0.0
- (b)
1.0
- (c)
2.4
- (d)
4.6
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
After how many days will you recommend supplying irrigation water to a crop having 0.8m root zone depth and grown in a soil having field capacity of 30%, permanent wilting=15% and density of soil=1.5 g/cc? The consumptive use for the crop is 5 mm/day and only 60% of available moisture is permitted to be availed.
- (a)
9 days
- (b)
15 days
- (c)
21 days
- (d)
40 days
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 moisture depth available for evaporation transpiration in root zone of 1 m depth soil if dry weight of soil is 1.5 g/cc, field capacity is 30% and permanent wilting point is 10%?
- (a)
450 mm
- (b)
300 mm
- (c)
200 mm
- (d)
150 mm
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
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
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
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
Uplift pressures at points E and D (see Fig. A) of a straight horizontal floor of negligible thickness with a sheet pile of downstream end are 28% and 20% respectively. If the sheet pile is at upstream end of floor (see Fig. B), the uplift pressures at points D1 and C1 are
- (a)
68% and 60% respectively
- (b)
80% and 72% respectively
- (c)
88% and 70% respectively
- (d)
100% and zero respectively
Khosla's safe exit gradient for design of weirs will be the lowest for the soil type
- (a)
fine sand
- (b)
coarse sand
- (c)
gravels
- (d)
silt
According to Khosla's theory of independent variables for seepage below hydraulic structure, the exit gradient in the absence of a downstream sheet pile is
- (a)
zero
- (b)
1
- (c)
\(\infty \)
- (d)
2
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)
\(\frac { b }{ H } =\frac { 1 }{ K\sqrt { G-K } } \)
The consumptive use of water for a crop during a particular stage of growth is 2.0 mm/day. The maximum depth of available water in the root zone is 60 mm. Irrigation is required when the amount of available water is 50% of the maximum available water in the root zone. Frequency of irrigation should be
- (a)
10 days
- (b)
15 days
- (c)
20 days
- (d)
25 20 days
As per Lacey's method for design of alluvial channels, identify the true statement from the following
- (a)
Wetted perimeter increases with an increase in design discharge
- (b)
Hydraulic radius increases with increase in silt factor
- (c)
Wetted perimeter decreases an increase in design discharge
- (d)
Wetted perimeter increase with an increase in silt factor
A weir on a permeable foundation with downstream sheet pile is shown in the figure below. The exit gradient as per Khosla's method is
- (a)
1 in 6.0
- (b)
1 in 5.0
- (c)
1 in 3.2
- (d)
1 in 2.5
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
canal irrigates a portion of a culturable command area to grow sugarcane and wheat. The average discharge required to grow sugarcane and wheat are respectively 0.36 and 0.27 cumec. The time factor is 0.9. The required design capacity of the canal is
- (a)
0.36 cumec
- (b)
0.40 cumec
- (c)
0.63 cumec
- (d)
0.70 cumec
Two irrigation channel A and B are designed using Lacey's theory. If the medium diameter of silt particles are the same for both the channels and if discharge in channel A is 60% less than at B, then between these two channels,
- (a)
channel A has smaller longitudinal slope
- (b)
channel B has smaller longitudinal slope
- (c)
channel A has smaller hydraulic radius
- (d)
channel B has larger wetted perimeter
The leaching requirement of a soil is 10%. If the consumptive use requirement of the crop is 90 mm. then depth of water required to be applied in the field is
- (a)
80 mm
- (b)
90 mm
- (c)
100 mm
- (d)
110 mm
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 permanent wilting point will be
- (a)
14.29%
- (b)
27.99%
- (c)
30.72%
- (d)
19.11%
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
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
The irrigated area of a watercourse is 500 ha. The intensity of crop X in this area is 50%. The duration for plantation of crop X is 12 days and total depth of water required by the crop is 45 cm on the field during transplantation period is 15 cm
The duty of irrigation water for the crop at the head of channel is
- (a)
230.4 ha/cumec
- (b)
325.6 ha/cumec
- (c)
345.6 ha/cumec
- (d)
172.8 ha/cumec
In an irrigation farm, during winter season the consumptive need is 15 cm. The effective rainfall is 4 cm, losses in the field=25% of applied water and losses during conveyance=12.5% of water input to the conveyance system.
Match List I with List II and select the correct answer using the codes given below the lists.
List I | List II |
---|---|
P. Net irrigation requirement | 1. 50.3 cm |
Q. Field irrigation requirement | 2. 44 cm |
R. Gross irrigation requirement | 3. 11 cm |
- (a)
P Q R 1 2 3 - (b)
P Q R 1 3 2 - (c)
P Q R 2 1 3 - (d)
P Q R 3 2 1