Revenue loss to the exchequer is seemingly the only tangible cost of illegally mined sand, but the impact that it has on environment and ecology is far greater and far graver, caution environmentalists and water conservation experts.
From forcing the river to change its course, to affecting the groundwater tables and adversely impacting the habitat of micro-organisms, the ramifications of illegal sand mining are many.
“Sand is important for ground water recharge, on a riverbed it acts as a link between the flowing river and the water table and is part of the aquifer,” said Manoj Misra of the NGO Yamuna Jiye Abhiyan.
Illegally dredged sand, Mr. Misra said, is equivalent to robbing water. “Sand holds a lot of water, and when it is mindlessly mined and laden on to trucks, large quantities of water is lost in transit.”
The negative impact of illegal sand mining far outweighs the economic benefits, pointed out Himanshu Thakkar of the South Asia Network on Dams, Rivers and People. “There is a perception that sand and boulders are useless and rivers have a lot of sand. This is incorrect, because they are crucial for the sustained existence of the river and perform many functions.”
“We have seen the impact of tampering with the rivers and their resources in the recent Uttarakhand floods. When sand and boulders are removed in an unimpeded way using heavy machines, the erosion capacity of the river increases. Sand and boulders prevent the river from changing the course and act as a buffer for the riverbed.” Mr. Thakkar added: “In Vishnuprayag the boulders that came down with the river water damaged a side of the dam and the waters spread out across causing heavy damage.”
Unplanned and rampant removal of sand from riverbeds also amounts to destroying the habitat of biodiversity, Mr. Misra said. “There are a lot of micro-organisms that are not visible and widely known, but are critical to soil structure and fertility. When we dredge sand, we literally take away their habitat,” he said, adding: “It is estimated that in Noida and Greater Noida alone the loss to the exchequer is about Rs.1,000 crore, but the impact that sand mining, which is simply put theft on environment and ecology, cannot even be calculated.”
Despite a Supreme Court order that prohibits sand mining without the requisite clearance from the required authorities and places limits on the quantities that can be mined, thousands of tonnes of sand is being illegally mined to meet the rising demand of construction industry and for extraction of minerals.
Experts are also worried about the methods used for mining, cautioning against the use of intrusive techniques such as the use of explosives and heavy excavator machines. “When we mine sand using excavator machines and through blasting techniques the results can be destructive. In the Himalayan areas especially sand mining should be carried out manually. Excessive in-stream sand mining causes degradation of rivers, therefore, there has to be periodic assessment of how much sand can be sustainably mined, as the quantity can vary from a river to river and within a river from stretch to stretch,” said Mr. Thakkar.