Q.1) In arid areas with an uneven land surface most suitable method of irrigation is –
A) Sprinkler irrigation
B) Basin method
C) Furrow irrigation
D) Check flooding
Sprinkler Method : In this method, the water is distributed through sprinklers in the form of sprays over plants and soil. This method is adopted in following conditions :
- Land cannot be prepared for surface methods
- Slopes are excessive
- Topography is irregular
- Soil is erosive
- Soil is excessively permeable or impermeable
- Seepage loss is more
- When fertilizers and insecticides are to be mixed with irrigational water
- Availibility of water is difficult
Basin Method : In this method, water is applied in the form of basin or small pond.
Furrow irrigation : In this method, water is applied to the field in small channels, or furrows, between crop rows. This method is often used for row crops and can be an efficient way to irrigate in areas with low water availability.
Check Flooding : In this method, water is applied by allowing it to flow into series of small ditches.
Q.2) An irrigation project is called as a major project if the culturable command area (ha) is more than :
The Culturable Command Area for dufferent types of project are as follows :
- For Minor Irrigation Project – less than 2000 ha
- For Medium Irrigation Project – 2000 to 10000 ha
- For Major Irrigation project – more than 10000 ha
Q.3) Kor watering is the irrigation water supplied to the crop :
A) At the time of sowing
B) After harvesting the crop
C) Just prior to harvesting
D) When the crop has grown few centimeters and water is applied for the first time
Crops require maximum water during first watering after the crops have grown a few centimeters. The first watering is known as kor watering and the depth applied is known as kor depth.
Q.4) The salt concentration in irrigation water is generally measured by :
A) pH value
B) SAR value
C) BOD value
D) Electrical conductivity value
Q.5) Crop ratio is the ratio of area irrigated _______.
A) In kharif season to rabi season
B) In rabi season to kharif season
C) Under perennial crop to total crop
D) Under perennial crop to non-perennial crop
Crop Ratio, CR = CCA under Rabi/ CCA under Kharif
CCA = Culturable Command Area
Q.6) The amount of water retained in solid waste, which after saturation is allowed to drain freely is termed as :
A) Natural yield
B) Ambient moisture
C) Field Capacity
D) Retained Moisture
Field capacity refers to the maximum amount of water that soil can hold against gravity after excess water has drained away.
Q.7) What is the effect of Lining on Irrigation canals?
A) Does not change the water logging area
B) Causes the leakage of water
C) Decreases the water logging area
D) Increases the water logging area
Advantages of Canal Lining :
- Less maintenance
- Reduced seepage loss
- Reduce the chance of water logging
Q.8) If the SAR (Sodium Adsorption Ratio) of the irrigation water is 15, then it is classified as –
A) Low sodium water
B) Medium sodium water
C) High sodium water
D) Very high sodium water
SAR range :
0 to 10 = Low Sodium water
10 to 18 = Medium Sodium water
18 to 26 = High Sodium water
> 26 = Very high Sodium water
Q.9) A canal which is aligned at right angles to the contour is called :
A) Side slope canal
B) Contour canal
C) Ridge canal
D) Watershed canal
Q.10) The main cause of silting up a channel :
A) Defective outlets
B) Inadequate slope
C) Defective head regulator
D) All of the above
Main causes of silting up a channel are :
- Non-regime section
- Inadequate slope
- Defective outlets
- Defecyive head regulator
Q.11) Thickness of concrete lining is governed by :
A) Slope of bank
B) Requirement of imperviousness
C) Thumb rule for providing nominal thickness
D) Requirement of imperviousness and structural strength
Factors on which thickness of lining depends are as follows :
- Nature of canal
- Canal slope bank
- Canal capacity
- Special requirement of impervoiusness
- Structural strength of resist cracking on slight movement of subgrade
Q.12) Canal designed on the basis of uniform flow is _____.
A) Unlined canal
B) Lined canal
C) Rigid Boundary canal
D) Both lined and unlined canal
Q.13) Crest level is kept low with large gates in the _____.
Barrage is a concrete structure built across river/stream to control flow of water and create a reservoir. It includes gates or valves that can be opened or closed to regulate the water level.
Q.14) Isobar is a line that joins points of equal ______.
C) Rainfall Depth
D) Atmospheric Pressure
Q.15) A rainfall with intensity greater than 4 mm/h but less than 6mm/h, referred as _______.
A) Light rain
B) Moderate rain
C) Heavy rain
D) Very heavy rain
Rainfall intensities with ranges are as follows :
Light rain – < 2.5 mm/h
Moderate rain – 2.5 to 7.6 mm/h
Heavy rain – > 7.6 mm/h
Very heavy rain – > 50 mm/h
Q.16) The most accurate method of finding the average depth of rainfall over an area is _______.
A) Arithmetic mean method
B) Isohytel method
C) Theissen polygon method
D) All of the above
Accuracy of finding average depth by various methods is as follows :
Arithmetic mean method < Theissen polygon method < Isohytel method
Arithmetic Mean Method : The arithmetic mean method is a straightforward technique for estimating average hydrological variable values for a given region or time period. It involves calculating the arithmetic mean of the variable’s values throughout the area or time period. This approach makes the assumption that the variable’s values are equally distributed throughout the region or time frame and do not significantly vary over space or time.
Isohytel Method : Based on the contours of equal precipitation or other variables that influence hydrological processes, the isohytel method is a technique used to estimate average values of hydrological variables over a specific area. Drawing lines between points of equal precipitation or other variables, known as isohyets, and then computing the average value of the variable within each isohyet are the steps in the procedure. In areas where precipitation is the primary driver of hydrological processes, this technique is frequently applied.
Theissen Polygon Method : The Theissen polygon method is a technique used to estimate average values of hydrological variables over a certain area based on the spatial distribution of data points. The method involves drawing polygons around each data point in such a way that the boundary of each polygon is equidistant to its data point and the nearest neighboring data points. The average value of the variable within each polygon is then used to estimate the average value of the variable over the entire area. This method is commonly used when the data points are unevenly distributed over the area and when there is significant spatial variability in the variable being estimated.
Q.17) The recording type rain gauge gives _______.
A) Monthly rainfall
B) Mass curve of rainfall
C) Total rainfall of 24 hrs period
Weighted Bucket type rain gauge (Recording type gauge) gives a plot of accumulated rainfall values against the elapsed time and the curve formed is called mass curve.
Q.18) Water loss through leaves of plants is termed as :
B) Surface Evaporation
Q.19) Which of the following instruments is not connected with stream flow measurement?
B) Echo-depth recorder
C) Electromagnetic flow meter
D) Sounding weight
- Hygrometer is used to measure humidity.
- Echo-depth Meter is used to measure the depth of water in a water body such as ocean, lakes etc.
- Electromagnetic flow meter is used to measure flow rate of a fluid such as wastewater.
- Sound weight is used to measure depth of water body.
Q.20) A hydrograph is a plot of ________.
A) Stream flow vs Time
B) Direct run-off vs Time
C) Precipitation vs Time
D) Surface run-off vs Time