Maity, P. (2014). A coastal groundwater management model with Indian case study. Proceedings of the Institution of Civil Engineers: Water Management, 167 (3), 126-140. A coastal groundwater management model with Indian case study AbstractThe complexity of the hydrogeological setup in coastal areas calls for the adoption of scientific groundwater management techniques. Excessive withdrawal of groundwater in coastal zones will lead to depression of the water table, with associated hazards such as putting the well out of use, rendering abstraction uneconomic with increased lift. A sustained regional groundwater drawdown below sea level runs the risk of saline water intrusion, even for confined coastal aquifers. Uncontrolled groundwater development may lead to reversal of the freshwater gradient, thereby resulting in saline water ingress into coastal aquifers. There are, however, several established methodologies to control and minimise the problems associated with groundwater extraction followed by saline water intrusion. This study developed a convenient and easily implementable analytical model for coastal groundwater management aimed at the control of saltwater intrusion. The technique includes withdrawal of coastal freshwater by means of qanat-well structures associated with artificial recharge through rainwater harvesting aided by percolation ponds and recharge wells. The proposed methodology is suitable specifically for not highly urbanised coastal areas with significant annual precipitation, good hydraulic conductivity of the aquifer and a low depth of fresh groundwater. As a case study, the model is applied to a coastal zone of the Purba Medinipur district of West Bengal, India. Adequate quantifications of the efficiency of the methodology are incorporated and relevant conclusions are drawn. The complexity of the hydrogeological setup in coastal areas calls for the adoption of scientific groundwater management techniques. Excessive withdrawal of groundwater in coastal zones will lead to depression of the water table, with associated hazards such as putting the well out of use, rendering abstraction uneconomic with increased lift. A sustained regional groundwater drawdown below sea level runs the risk of saline water intrusion, even for confined coastal aquifers. Uncontrolled groundwater development may lead to reversal of the freshwater gradient, thereby resulting in saline water ingress into coastal aquifers. There are, however, several established methodologies to control and minimise the problems associated with groundwater extraction followed by saline water intrusion.This study developed a convenient and easily implementable analytical model for coastal groundwater management aimed at the control of saltwater intrusion. The technique includes withdrawal of coastal freshwater by means of qanat-well structures associated with artificial recharge through rainwater harvesting aided by percolation ponds and recharge wells. The proposed methodology is suitable specifically for not highly urbanised coast...

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Purba Midnapur, a coastal district of West Bengal in India, is under a serious threat concerning the deterioration of groundwater due to seawater encroachment. The upper soil horizon of Purba Midnapur consists of alternating deposits of clay and sand of marine origin. As with all marine deposits, rounded grains and high porosity are dominant characteristics. The coastal line upto 40 km wide tract is being contaminated due to the movement of saline water into aquifers of fresh water. Thus groundwater has become unfit for domestic uses and irrigation purpose. Due to extraction of groundwater, the water table is distorted like a cone of depression resulting in the associated risk like defunct well and making the abstraction uneconomical due to increased lift. Therefore immediate measures are required to control saline water ingression into the coastal aquifers. This paper suggests some measures for controlling saline water ingression in the area concern.

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.

-The work described in this paper is aimed towards conducting a thorough and in-depth field based study on the groundwater development and water quality variation in the district of Purba Medinipur, West Bengal, India. 20 nos. locations were selected along the coastal belt of the study area to investigate the groundwater quality. Based on the field test results,contour line were plotted for Chloride concentration. The 3-Dimensional views of piezometric surface pre monsoon [ 2006 ], pre-monsoon and post-monsoon average piezometric surfaces [2004] had also been developed. The subsurface characterization and the groundwater quality analysis were thereafter utilized to obtain the probable path of saline water ingress into the aquifers of the study area. Owing to heterogeneity of the aquifer in the selected locations, the spatial irregularity in salinity was observed to be significant. The present study was carried out to understand the quality of ground water and delineate the subsurface formations in an area of Purba Midnapur district. The physico chemical studies involve pH value, hydraulic conductivity, total hardness, anions (HCO, Cl, CO) and Fe.