This set of Engineering Hydrology Multiple Choice Questions & Answers (MCQs) focuses on “Flood Control – Set 3”.
1. Which of the following methods help to reduce flood damage by channel improvement?
a) Increasing channel roughness
b) Creating multiple meanders
c) Reducing the slope
d) Removing vegetation from channel perimeter
View Answer
Explanation: One of the basic motives of channel improvement for flood control is to increase the capacity of the channel to allow more flood water per unit time. This can be achieved by clearing all the vegetation growing on the sides and bottom of the channel.
2. Cut-off channels helps in flood management in rivers.
a) True
b) False
View Answer
Explanation: Creating cut-off channels by short circuiting the meandering loops of the rivers is a form of channel improvement technique to help in flood control. This enables the river to take a single path and the meander gets deposited with sediments.
3. Which of the following combinations for a channel is most suitable to achieve best results in flood management?
a) Increasing width and roughness
b) Increasing width and decreasing roughness
c) Decreasing width and increasing roughness
d) Decreasing width and roughness
View Answer
Explanation: Increasing the width of a river naturally increases the discharge carrying capacity of the river channel. Along with that, reducing the roughness of the channel also facilitates it to carry more discharge compared to a rough channel.
4. What is the ideology behind using watershed management methods to manage floods?
a) Completely prevent the occurrence of flood
b) Delay the flood
c) Use all flood water for practical purposes
d) Send all flood water to underground storage
View Answer
Explanation: Watershed management involves the use of land and water in a region in a such a way so as to reduce and delay the discharge before it gets into the river. This is done by improving the characteristics of the watershed that promote the delay of incoming runoff.
5. Which of the following is an unwanted result of watershed management aimed at reducing flood?
a) Low evaporation
b) High infiltration
c) Low soil erosion
d) High transpiration
View Answer
Explanation: Watershed management mainly aims at increasing the vegetation and improving the soil cover of the region. These must result in increased infiltration capacity of soil, higher rate of evapotranspiration and reduced soil erosion from the area.
6. Which of these practices/works are not used along with watershed management in order to manage floods?
a) Nala bunds
b) Check dams
c) Contour farming
d) Floodways
View Answer
Explanation: Using structures like nala bunds and check dams and practices like contour bunding and zing terracing enhance process of flood management when done in conjunction with watershed management. These primarily aim at reducing the velocity of flow and hence reduce the erosion of soil.
7. Which of the following is not true with respect to watershed management as a flood control technique?
a) Increases dry weather flow
b) Suitable for extreme floods
c) Delays incoming flood
d) Improves soil infiltration
View Answer
Explanation: All the cumulative effects of watershed management are sufficient only in managing the effects of small to medium floods. These changes of a catchment will most likely not have any effect on high levels of flood.
8. Which of the following structural method of flood control is the most suitable for controlling very high floods?
a) Storage reservoirs
b) Levees
c) Flood ways
d) Watershed management
View Answer
Explanation: Levees and flood are very limited by their design and features to contain high levels of flood. Watershed management also has a maximum effect on flood control upto only medium floods. Storage reservoirs is methods that focuses on storage using large capacities which is most reliable during high floods.
9. Which of the following is not a feature of flood plain zoning?
a) Controlling population
b) Preventing encroachment
c) Regulating land use
d) Dividing of areas into zones
View Answer
Explanation: Flood plain zoning is a non-structural flood control method which aims at regulating the rules regarding the use of land near rivers depending on the risk of flood occurrence. This is done by specifying zones for different activities.
10. A flood plain is prone to a flood of return period 25 years. Which of the following activities is acceptable in the region?
a) Houses
b) Parks
c) Commercial outlets
d) Factories
View Answer
Explanation: Parks are categorized separately from houses, offices and factories based on the effect of damages due to flood in an area. The risk of houses, outlets and factories in an area prone to 25 year flood is highly risky and are zoned accordingly.
Sanfoundry Global Education & Learning Series – Engineering Hydrology.
To practice all areas of Engineering Hydrology, here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
