# Engineering Geology Questions and Answers – Works of Streams and Rivers – 01

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This set of Engineering Geology Multiple Choice Questions & Answers (MCQs) focuses on “Works of Streams and Rivers – 01”.

1. What is the stage when the bankfull stage is crossed?
a) Overflow stage
b) Flood stage
d) Excess stage

Explanation: Normally, the river flows much below bankfull stage; abnormally; however, the bankfull, the stage may be crossed when the river is said to be in a flood stage.

2. The distance water travels in a unit time is __________
a) Speed
b) Unit speed
c) Velocity
d) Acceleration

Explanation: Velocity is defined as the distance water travels in a unit time within its channel.

3. What is the term defining the capacity of a river to transport the material?
b) Competence
c) Flow type
d) Fluvial

Explanation: Competence defines the capacity of a river to transport the material and is represented by the largest size of a particle that can be transported at a given velocity.

4. The term which is a function of cross-sectional area of the channel and flow velocity is __________
b) Competence
c) Discharge
d) Stream line

Explanation: Discharge is defined as the volume that passes at a given point in the channel in a unit time. It is a function of cross-sectional area of the channel and flow velocity.

5. The mechanical loosening and removal of the material from the rocks due to pressure exerted by the running water is called __________
b) Weathering
c) Hydraulic action
d) Cavitation

Explanation: Hydraulic action is the mechanical loosening and removal of the material from the rocks due to pressure exerted by the running water. The higher velocity, the greater is the pressure of the running water and hence greater is its capacity to bodily move out parts of the rock.

6. Which among the following is not true about cavitation?
a) It occurs everywhere
b) It is distinct process
c) It is a rare process
d) It is observed where river water acquires exceptionally high velocity

Explanation: Cavitation is a distinct and rare type of hydraulic action performed by running water. It is particularly observed where river water suddenly acquires exceptionally high velocity such as at the location of a waterfall.

7. There is a spontaneous change from liquid to vapour state and back to liquid state at the point of fall of waterfall.
a) True
b) False

Explanation: It is known that where stream velocity exceeds 12m/sec, the water pressure developed at the impinging points equals vapour pressure and there is spontaneous change from liquid to vapour state and back to liquid state at that point.

8. What is the principal method of stream erosion and involves wearing away of the bedrocks?
a) Hydraulic action
b) Abrasion
c) Attrition
d) Corrosion

Explanation: Abrasion is the principal method of stream erosion and involves wearing away of the bedrocks and rocks along the banks of a stream or river by the running water with the help of sand grains, pebbles and gravels and all such particles that are being carried by it as load.

9. The term for wear and tear of the load sediments being transported by a moving natural agency through the process of mutual impacts is __________
a) Hydraulic action
b) Abrasion
c) Attrition
d) Corrosion

Explanation: Attrition is the term used for the term for wear and tear of the load sediments being transported by a moving natural agency through the process of mutual impacts and collisions which they suffer during their transport.

10. Factor which doesn’t affect velocity is __________
b) Volume of the water in the stream
c) Type of water flowing
d) Roughness of the channel