Groundwater withdrawal and land subsidence: A study of Singur Block, West Bengal, India

Land subsidence is a slow imperceptible geological process referring gradual decrease in the elevation of land surface. It can be occurred due to many reasons such as, underground mining, extraction of oil, gas, water beneath the surface, natural settlement, hydro compaction, drainage of organic soil etc. Broadly the occurrence of subsidence can be classified into two reasons, natural and anthropogenic causes. Anthropogenic causes play a leading role in a short period of time. The present work is an attempt to measure land subsidence of Singur block, district Hooghly, West Bengal due to ground water extraction. It is found from the observation that the rate of decline of static water table, the depth of total aquifer system and the hydrogeological characteristics of the aquifer control the rate of subsidence of the area. The whole work is done based on secondary data sources. The average rate of subsidence was 0.92 mm/year during 19982002 which increased to 8.7 mm/year during 2002 – 2006. The estimated average rate of land subsidence is 6.13 mm/year for 1 m drop of static water table.