This set of Engineering Hydrology Multiple Choice Questions & Answers (MCQs) focuses on “Groundwater – Recharge”.
1. What is the groundwater recharge that takes place by altering the natural conditions of the area called?
a) Artificial recharge
b) Incidental recharge
c) Natural recharge
d) Semi-natural recharge
View Answer
Explanation: When the infiltration of surface water into groundwater systems takes place by modifying the existing natural conditions of the area, the type of recharge is known as artificial recharge.
2. Which of the following is not true regarding incidental recharge?
a) The infiltration of surface water is natural
b) Seepage comes from irrigated lands
c) Supply of surface water is artificial
d) Conditions are changed to enhance the infiltration
View Answer
Explanation: Groundwater recharge also takes place due to irrigated lands. In such a case, the supply of water is artificial while the infiltration process is natural. This type of recharge is known as incidental recharge.
3. Which of the following is not a suitable reason to artificially recharge an aquifer?
a) To increase the quantity of available groundwater
b) To reduce saltwater intrusion
c) To reduce damage to environment
d) To conserve runoff
View Answer
Explanation: In artificial recharge, the amount of water being infiltrated is enhanced by changing the natural conditions. The main reasons for adopting artificial recharge are – to conserve runoff, increase the groundwater storage and reduce saltwater intrusion.
4. Which of the following is not an example of artificial aquifer recharge?
a) Sprinklers
b) Injection wells
c) Subsurface dykes
d) Percolation tanks
View Answer
Explanation: Sprinklers are used in irrigation and it causes recharge naturally even though the supply is artificial. This is incidental recharge. The common methods of artificial recharge are spreading, injection wells, subsurface dykes, percolation tanks, check dams, etc.
5. Which of the following is not a method used for the estimation of recharge?
a) Specific yield method
b) Induced recharge method
c) Groundwater level fluctuation method
d) Rainfall infiltration factor method
View Answer
Explanation: The methods recommended as per the Groundwater Resource Estimation Committee are groundwater level fluctuation method or specific yield method and rainfall infiltration factor method.
6. As per the groundwater level fluctuation method, what will be the recharge in a non-monsoon month if the rainfall during that month is 5% of the normal annual rainfall?
a) Zero
b) 5% of average monthly recharge
c) 50% of average monthly recharge
d) 95% of average monthly recharge
View Answer
Explanation: The calculations for the groundwater level fluctuation method are based on the monsoon data. For a non-monsoon month, if the rainfall is less than 10% of the normal annual rainfall, then the recharge during that month is taken as zero.
7. The total annual recharge as per the specific yield method is obtained as per which of the following?
a) Recharge during monsoon months
b) Recharge during non-monsoon months
c) Sum of recharge during monsoon and non-monsoon months
d) Difference of recharge during monsoon and non-monsoon months
View Answer
Explanation: The recharge during monsoon months is calculated as per the data of the monsoon months. For non-monsoon months, the recharge may or may not be there depending on the value of monthly rainfall. Therefore, total recharge is obtained as the sum of recharge during both monsoon and non-monsoon months.
8. Rainfall infiltration method for recharge estimation is applicable in areas for which groundwater level monitoring is not available.
a) True
b) False
View Answer
Explanation: Rainfall infiltration factor method is the second method recommended by GREC for the estimation of recharge. It is to be used in areas where groundwater level monitoring is inadequate and data not available.
Sanfoundry Global Education & Learning Series – Engineering Hydrology.
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