Threat of land subsidence in and around Kolkata City and East Kolkata Wetlands,West Bengal,India |
| |
| Authors: | P SAHU P K SIKDAR |
| |
| Institution: | (1) Department of Environment Management, Indian Institute of Social Welfare and Business Management, Kolkata, 700 073, India;(2) Department of Environment Management, Indian Institute of Social Welfare and Business Management, Management House, College Square (West), Kolkata, 700 073, India; |
| |
| Abstract: | This paper attempts to estimate the possible rate of land subsidence of Kolkata City including Salt Lake City and the adjoining
East Kolkata Wetlands located at the lower part of the deltaic alluvial plain of South Bengal basin. Demand of groundwater
for drinking, agricultural and industrial purposes has increased due to rapid urbanization. The subsurface geology consists
of Quaternary sediments comprising a succession of clay, silty clay and sand of various grades. Groundwater occurs mostly
under confined condition except in those places where the top aquitard has been obliterated due to the scouring action of
past channels. Currently, the piezometric head shows a falling trend and it may be accelerated due to further over-withdrawal
of groundwater resulting in land subsidence. The estimated mean land subsidence rate is 13.53 mm/year and for 1 m drop in
the piezometric head, the mean subsidence is 3.28 cm. The surface expression of the estimated land subsidence is however,
cryptic because of a time lag between the settlement of the thick low-permeable aquitard at the top and its surface expression.
Therefore, groundwater of the cities and wetland areas should be developed cautiously based on the groundwater potential to
minimize the threat of land subsidence. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
