ENVIRONMENTAL IMPACT ASSESSMENT OF RIVER BED MINING

Abstract

Sand has become a very important mineral for the expansion of society. Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. River sand is one of the world's most plentiful resources (perhaps as much as 20% of the Earth's crust is sand) and has the ability to replenish itself. River sand is vital for human well being & for sustenance of rivers. India is a developing country due to this rapid urbanization is taking place which increases the pressure on sand mining from river and parallely due to this activity most important resources are adversely effected. Mining of sand, from river is depleting the waters of the rivers. While the construction boom fuels the demand, weak governance and rampant corruption are facilitating uncontrolled and illegal mining of sand and gravel in the rivers, threatening their very existence. This mindless, unrestrained and unregulated activity is posing threats of widespread depletion of water resources which may lead to avoidable food shortages and hardships for the people. The total number of parts of riverbeds presently identified for auction in the State of Himachal Pradesh is about 300 and out of this about 110 parts of river beds are under operation. In addition, about 156 leases in river beds have been granted for the establishment of stone crushers and about 14 leases have been granted for setting up of screening plants/hollow blocks units. In total about 47.3 sq.km (i.e. 0.085% of the State) area is involved in rivers/stream bed mining. In Himachal Pradesh also some of the river has been adversely effected river bed mining one such river is the Swan River flowing through Una district of the state. The width of the river has increased and fertile land situated on both banks is turning barren due to silt deposits. Besides some of the fertile land situated near the banks has been eaten away during the floods. Swan River has a total catchment area of 1200 Sq. Km and has a length of 65 Kms in Himachal Pradesh. There are 73 tributaries in the catchment area and almost all the tributaries are in the range of river bed mining, few of them are adversely affected by river bed mining. This mining activity threatening bridges, sand mining transforms the riverbeds into large and deep pits, as a result, the groundwater table drops leaving the drinking water wells on the embankments of these rivers dry. Bed degradation from in stream mining lowers the elevation of stream flow and the floodplain water table which in turn can eliminate water table-dependent woody vegetation in riparian areas, and decrease wetted periods in riparian wetlands. For locations close to the sea, saline water may intrude into the fresh water body. It is observed that the stage of ground water development in Una valley is 97.63 percentages and there is a falling water table trend with significant decline in pre and post monsoon which indicate that it is in critical zone. It has become clear that short-term benefits must be weighted and balanced against the resulting long-term effect of resource depletion and decline in the state of the environment. Increasing evidence of potential problems from over-extraction of river/stream beds, and the community increasing demand on and expectation of the river system. Therefore, in future Riverbed mining should be based on the principle of sustainable development