Methodology for Groundwater Extraction in the Coastal Aquifers of Purba Midnapur District of West Bengal in India under the Constraint of Saline Water Intrusion

The objective of this paper is to assess the field-based study on the sub-surface characteristics and groundwater quality variation in the coastal region of Purba Midnapur district, West Bengal, India. The fact that the coastal area receives inadequate surface water, the use of groundwater has become increasingly important for domestic, irrigation and industrial purposes; however threat exists associated with groundwater over-exploitation that leads to the intrusion of seawater. Hydro-geochemical site characterizations at individual locations were selected and detailed investigations were carried out on subsoil condition and groundwater quality assessment. Based on the field test results, contour lines were plotted for chloride concentration. Three dimensional views of piezometric surface of pre-monsoon, monsoon and post-monsoon depth to groundwater level and pre-monsoon piezometric surfaces contours had also been developed. This paper presents a mathematical analysis for estimating the safe yield from shallow vertical well and the qanat well structures coupled with vertical risers are presented as a viable solution to the problem of upconing below deep vertical wells. The vertical wells may not be feasible in several situations and qanat coupled with vertical risers may be successfully used in Purba Midnapur geology context.