1. Decreased salinity in the river
2. Pollution of groundwater
3. Lowering of the water-table
Select the correct answer using the code given below:
Explanation
Sand mining is the extraction of sand, mainly through an open pit (or sandpit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds.
Statement 1 is incorrect: Sand mining typically does not directly affect the salinity of the river. Salinity is more influenced by factors like the influx of seawater in coastal areas, evaporation rates, and the presence of saline minerals in the riverbed.
Statement 2 is correct: The amount of suspended particles in the water at the excavation site and downstream increases due to increased riverbed and bank erosion. This process stirs up the sediments and increases the chance of contamination of groundwater.
Statement 3 is correct: Heavy sand mining causes removal of sand and gravels from the riverbed. Due to this the groundwater table drops leaving the drinking water wells on the embankments of these rivers dry. Alteration of rivers, damage to river biodiversity, altered sediment budget lead to poor water quality, worsen water scarcity threat to coastal communities, damage to public and private property.