Environmental Impact of Sand Mining: a Case Study along the Lower Reaches of Ajay River, West Bengal, India

Indiscriminate and unscientific sand mining has become a serious environmental threat to the river systems and its surrounding environment. The rapid rate of urbanization has increased the demand for sand, which is supplied from river bed through sand mining. Sand mining from river bed results in channel degradation and erosion, change in local gradient, head cutting, increased turbidity, bank erosion and sedimentation of riffle areas and ruins its flow regimes and total sedimentary environment. In lower reaches of Ajay river, unscientific sand mining is a serious issue from Illambajar (Birbhum) to Mongalkot (Burdwan) fluvial environment of Ajay river basin, which is highly affected by in-stream sand mining. Natural morphological characteristics of Ajay river are changed and damaged due to over mining of sand. Excessive in-stream sand mining is a threat to Illambajar bridge and Nutanhut bridge. River embankments are also affected by river bed mining. Sand mining also affects the adjoining groundwater system. In Mongalkot and Ketugram Blocks (Burdwan), ground water level becomes lower than the past. Sand mining also generates extra vehicle traffic, which negatively impairs the environment and pollution level continuously gets higher. Total station survey was carried out to detect the changes in river bed. Topographical sheets and satellite images were geocoded to extract past status of river health and tried to correlate with the present situation. GPS (Handheld-Germin etrexH-20) was used as necessary tool in the present study. The main objective of the present study is to evaluate the impact of sand mining on riparian environment.