The economic development is fueling the growth of infrastructure and construction activities which is pushing the demand for sand – a vital ingredient of cement concrete and mortar. In concrete making, each tonne of cement requires 6-7 tonnes of sand and gravel. Globally, sand and gravel form the largest volume of solid material extracted and the highest volume of raw material use after water. Formed by natural erosive processes since ages, they are now extracted at rates much higher than their replenishment.
Traditionally, rivers [Interesting facts about Rivers] have supplied this important component which is formed by weathering of rocks over a long period. However, now excessive and indiscriminate mining of sand (which is many times higher than its replenishment rate) has become a serious issue in a variety of ways which can’t be judged from the economic cost of sand alone. It is a grave issue for people involved with the river basin management, shore development and harbor development, environmentalists and all concerned citizens.
But despite the extraction of colossal quantities of sand and gravel and its significant adverse impact on the environment the issue of over extraction remain mostly ignored by the policy makers, and the common man is hardly aware of the negative consequences. Absence of reliable data also widens the gap between the magnitude of the problem and public awareness of it.
Sand and Riverbed
Sand is formed through erosion of rocks due to mechanical forces. In the process the weathered rocks forms gravel and then sand. So, sand is a mixture of finely divided rock and mineral particles between 150 micron to 4.75 mm in diameter (IS 383-1970). Its composition is highly variable depending upon the local region but most commonly it consists of silica (silicon dioxide) as quartz which is chemically highly inert and considerably hard to resist weathering.
Sand and gravel of the riverbed provide an ideal substrate for many benthic organisms for breeding, spawning, feeding and hiding. Sand also acts as an efficient filter for removing pollutants and thus maintains water quality. So damaging riverbed means destroying the chain of all these organisms.
Adverse Impact of Excessive Sand Mining
Ill effects of over extraction of sand from river beds can be broadly categorized in three ways:
Large scale removal riverbed materials and dredging below the streambed alters the channel form and shape, that, in turn, has several consequences such as erosion of the riverbed and banks, increase in the channel slope, and changes in the channel morphology. Removed sand is a direct loss to the river system. It causes deepening of rivers and estuaries; it also enlarges river mouths and coastal inlets. It is also a threat to bridges and nearby structures.
2. Water Quality
In-stream sand mining activities degrade the quality of river water. The short term turbidity is increased at the mining site due to re-suspension of sediments and organic particulate matter – oil spills and leakages from mining machinery and vehicles further aggravate the issue. Increase in suspended particles directly affect the water users – by significantly increasing water treatment costs – and undermine the aquatic ecosystem.
Sand removal turns riverbeds into large and deep pits which lowers groundwater level in the wells of the nearby areas; thus, affecting the local groundwater availability.
The stability of sand and gravel bed depends upon a delicate balance of the stream flow, sedimentation and channel form. Native species in streams are uniquely adapted to the stable bed structure. Unstable stream channels are inhospitable to most aquatic species. Bed degradation and sedimentation have negative impact on aquatic life, disturbing the species attached to streambed deposits – leading to loss of biodiversity.
Degraded stream habitats also result in loss of fishery productivity. Physical disturbances due to human activities also leads to interruptions in the nesting/breeding activities. For example, in the National Chambal Sanctuary mining of sand adversely affected ghariyals who use sand banks for nesting and basking. They lay eggs under the sand beds – which were destroyed by sand mining activities.
This booklet from the Ministry of Environment and Forests gives comprehensive details of environmental impact of excessive sand mining.
Curse of Illegal Sand Mining
India’s booming construction industry employs over 35 million people and is valued at around $126 billion per year. Officers responsible for implementing ban on sand mining are always at risk.
Here is the latest, from Karnataka.
“IAS officer Ujjwal Kumar Ghosh narrowly escaped unhurt when a lorry carrying illegally mined sand almost collided with his car in the early hours of Saturday at Dandoti village in Chittapur taluk. Ujwal, a 2008 batch officer is the Deputy Commissioner of Kalaburagi district.” Reported by The New Indian Express, March 27, 2017.
Durga Nagpal’s was another high profile incident of 2013 when she was abruptly transferred when she took on the sand mafia in UP’s Ghaziabad area. Such actions against law enforcing officers is unfortunately a regular news, indicating political patronage of the sand mafia.
Supreme Court Order
In 2012 judgment SC had directed all Union Territories and State Governments to seek Environmental Clearances (EC) from Ministry of Environment, Forest & Climate Change (MoEF&CC) for mining minor minerals even in less than 5 ha or renew the same after prior approval from the MoEF&CC. Before this order, mining areas of less than 5 ha were exempted from EC enacted under Environmental Impact Assessment (EIA)-2006.
The National Green Tribunal (NGT) has issued a restraint order against all sand mining activity being carried out across the country without environmental clearance. It was in response to the controversy surrounding the suspension of IAS officer posted as sub divisional magistrate (SDM) in Greater Noida in Gautam Buddh Nagar in Uttar Pradesh in 2013 after she cracked down on the mining mafia.
So, the intention of the government is clear. Now it need to raise public awareness on the issue in order to safeguard/ rejuvenate health of India’s river system and protect the environment.