Quiz: Civil Engineering
Topic: Irrigation & Hydrology
Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes
Q1. Yield of well will be ______ if permeability of soil is more.
Q2. The most effective farming method for returning minerals to the soil is
(a) Contour ploughing
(c) Crop rotation
Q3. A given piece of land is said to be waterlogged when:
(a) there is a water flowing on the land surface
(b) Capillary fringe reaches the root zone of plants
(c) Gravity drainage has ceased
(d) The permanent wilting point is reached
Q4. If specific yield of particular sand is 30% and its porosity is 50%, then the specific retention of the sand will be
Q5. Loam is
(a) A mixture of sand, silt and clay
(b) A mixture of gravel, sand and silt
(c) An impure form of limestone
(d) Is a wind blow deposit
Q6. Lacey’s theory is applicable to flow
(a) Through pipes
(b) In concrete lined channels
(c) Over spillways
(d) In alluvial rivers and canals
Q7. The minimum freeboard recommended for lined canal carrying discharge greater than 10 m³/s
(a) 0.15 m
(b) 0.60 m
(c) 1.25 m
(d) 0.75 m
Q8. The volume of rainfall which produces equal run-off is called
(a) Point rainfall
(b) Effective rainfall
(c) Average rainfall
(d) None of the above
Q9. A rainfall with an intensity of 5 mm/hr is classified as
(b) Light rain
(c) Moderate rain
(d) Heavy rain
Q10. According to Reyve’s formula for estimating floods, the peak discharge is proportional to
Sol. Yield of well is directly proportional to permeability of soil, hence permeability of soil is more, then yield of well will be more.
Sol. Crop rotation is the method of growing of crops one after another to improve the fertility of land and returning minerals to the soil.
Sol. A given piece of land is said to be water logged when
Capillary fringe reaches the root zone of plants.
Due to rise of water table up to ground level.
Area is full of salinity.
Specific yield (S_y) = 30%
Porosity (n) = 50%
Specific retention (SR) =?
Sol. Loam is a mixture of sand, silt and clay.
Sol. Lacey’s theory is applicable to flow in alluvial rivers and canals.
Discharge (m³/sec.) Freeboard (m.)
1 to 5 0.50
5 to 10 0.60
10 to 30 0.75
30 to 150 0.90
Sol. The volume of excess rainfall which produces equal run-off is called effective rainfall.
Intensity of Rainfall Rain type
0-2.5 mm/Hr. Light Rain
2.5-7.5 mm/Hr. Moderate rain
>7.5 mm/Hr. Heavy rain
Sol. Peak flood discharge by Reyve’s formula-
A= area in km²
Q= Peak flood discharge (m^3/sec)
Reyve’s formula is used for southern India catchments.