Hydrogeological characterization of the Quaternary aquifer of south Bengal Basin in India and the impact of urbanization on the groundwater resources of the system

• Published in: Hydrogeology journal Vol. 29; no. 4; pp. 1463 - 1484
• Main Authors: Banerjee, Sumanta, Sikdar, Pradip K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2021; Springer Nature B.V
• Subjects: Aquatic Pollution; Aquifers; Earth and Environmental Science; Earth Sciences; Geology; Geophysics/Geodesy; Groundwater; Groundwater quality; Groundwater resources; Hydrogeology; Hydrology/Water Resources; Land subsidence; Overdraft; Quaternary; Subsidence; Urbanization; Waste Water Technology; Water levels; Water Management; Water Pollution Control; Water quality; Water Quality/Water Pollution; Water resources; India; Groundwater management; Piezometric surface; Subsidence; Urbanisation impact; India
• ISSN: 1431-2174; 1435-0157
• DOI: 10.1007/s10040-021-02340-0

The study defines the hydrogeological framework of the Quaternary aquifer of south Bengal Basin, India, and the impact of urbanisation on the groundwater resources in and around the twin cities of Kolkata-Howrah. The estimated groundwater overdraft in 2016 was 408 × 10 3  m 3 /day, which lowered the piezometric surface by 34 cm. Due to the long-term decline of water levels at the rate of 13–37 cm/year, at some places the piezometric surface occurs below the base of the upper confining bed, generating unconfined conditions. This increases the chance of land subsidence and groundwater quality deterioration. The situation will worsen if the piezometric surface drops further due to over-pumping. The estimated land subsidence for a 1-m drop in the piezometric surface varies between 2.7 and 6.20 cm within the study area. The pre-monsoon groundwater trough represented by the −10 m isopotential line increased from an area of 19 km 2 in 1985 to 285 km 2 in 2016. Alarmingly, in just over three decades the area of the trough has increased by 15 times, at an average rate of 8.60 km 2 /year. The exponential expansion of the groundwater trough and the increased susceptibility of groundwater to hazards are the result of an increase of built-up area from 143 to 243 km 2 between 1985 and 2016. The urbanization happened mostly in the western part of the study area, which has resulted in the shift of the −10 m isopotential line towards the west and it will further shift in the future.