- Riverbed Degradation: Causes widening and lowering of the riverbed, leading to deepening of rivers and enlargement of river mouths
- Bank Erosion: Increases water velocity, which erodes river banks and can force rivers to change course
- Groundwater Depletion: Sand aquifers recharge water tables; their depletion causes a lowering of groundwater levels in nearby areas
- Saline Water Intrusion: In coastal areas, increased turbidity and river deepening lead to saline water ingress into fresh groundwater and rivers
- Flooding: Altered flow patterns and reduced sediment delivery increase flood risk in rivers and coastal areas
- Altered River Course: Excessive mining affects the regular course of the river, leading to changes in river ecology across India
Ecological & Biological Impacts
- Destruction of Benthic and Riparian Habitats: Sand and gravel form the substrate for bottom-dwelling organisms (benthos), aquatic plants, and insects. Mining destroys these breeding grounds.
- Threat to Endangered Species: * Gharials (Fish-eating crocodiles): Depend on pristine sandbanks for basking and nesting. Sand mining directly destroys their breeding sites (e.g., in the Chambal River).
- Disruption of Food Webs: High turbidity (cloudiness) caused by mining equipment blocks sunlight, reducing photosynthetic activity in aquatic plants. This triggers a collapse up the trophic levels, severely impacting local fisheries.
Socio-Economic Impact
- Damage to Critical Infrastructure: Bed degradation exposes the foundations of bridges, piers, and underwater pipelines, leading to structural failures (e.g., the collapse of the Mahad bridge in Maharashtra).
- Increased Flood Vulnerability: The destruction of natural floodplains and the alteration of river channels reduce the river’s capacity to absorb high-velocity flows, leading to flash floods downstream.
- Loss of Livelihoods: Depleted groundwater harms agriculture, while destroyed habitats decimate traditional fishing communities, driving rural distress.
Source: The Hindu