Here is Question No. 81 a part of our series on UPSC Prelims 2018
Q81. Which of the following is/are the possible consequence/s of heavy sand mining in riverbeds?
Decreased salinity in the river
Pollution of groundwater
Lowering of the water – table
Select the correct answer using the code given below: (a) 1 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3
Answer: B
Statement 1 is not correct: Depletion of sand in the streambed causes the deepening of rivers and estuaries, and the enlargement of river mouths and coastal inlets. It leads to decreased salinity in the river.
Statement 2 is correct: The sediment in the mining site, if it contains toxic material due to long-term accumulation, will cause groundwater pollution.
Statement 3 is correct: Riverbed becomes dry due to exposure to solar radiation, decreasing the surface and groundwater. It causes lowering of the water tables.
