निम्नलिखित में से कौन-सा/से नदी तल में बहुत अधिक बालू खऩन का/के संभावित परिणाम हो सकता है/सकते हैं ?
- 1.नदी की लवणता में कमी
- 2.भौमजल का प्रदूषण
- 3.भौम जलस्तर का नीचे चले जाना
नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए :
Read this question in English
Which of the following is/are the possible consequence/s of heavy sand mining in riverbeds?
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:
(a) 1 only · (b) 2 and 3 only · (c) 1 and 3 only · (d) 1, 2 and 3
उत्तर और व्याख्या · explanation in English
Answer: (b) केवल 2 और 3
Heavy sand mining harms groundwater in two ways: it can pollute it and it can pull the water-table down. It does not lower river salinity; near the coast it makes salt-water intrusion more likely.
- ✗ 1. Removing sand deepens the channel and weakens natural barriers, so salt water can enter aquifers; UNEP lists 'salination of aquifers' as a result of sand extraction. Salinity goes up, not down.
- ✓ 2. The sand layer filters water that seeps into the ground. The MoEFCC guidelines say mining can pollute groundwater by thinning this filter material, especially over recharge fissures.
- ✓ 3. Mining lowers the riverbed and river level, and groundwater in the adjoining flood plain drains towards it, so the water-table falls. The guidelines record this as a listed effect.
Remember · Heavy riverbed sand mining lowers the water-table, weakens the sand filter that protects groundwater, and raises salt intrusion risk near the coast.
Sources
- Sustainable Sand Mining Management Guidelines, 2016, MoEFCC (effects of sand and gravel mining) ↗ “Lowering of ground water table in the flood plain because of lowering of riverbed level as well as river water level takes place because of extraction and draining out of excessive ground water from the adjacent areas. … Polluting ground water by reducing the thickness of the filter material especially if mining is taking place at top of recharge fissures.”
- Our use of sand brings us 'up against the wall', says UNEP report (UNEP press release) ↗ “Extracting sand where it plays an active role, such as rivers, and coastal or marine ecosystems, can lead to erosion, salination of aquifers, loss of protection against storm surges and impacts on biodiversity”
Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·