72-Dissertation Report on An Approach for The Management of Groundwater in the Coastal Regions of West Bengal.

Abstract

The tittle of the dissertation work and report is "An Approach for the Management of Groundwater in the Coastal Region of West Bengal."Groundwater is most important natural resources and it serves as large subsurface water reservoir.The availability and quality of groundwater is degrading very rapidly in coastal areas. The depletion of groundwater happens due to the involvement of different factors like over pumping and over exploitation, sea level fluctuation, landuse changes, climatic variations etc. So to maintain the availability of groundwater the management is needed to be done. The proper management is required to maintain the sustainability of groundwater resources. The management should be economically sound and environmentally beneficial. West Bengal has coastline of 210km and coastal region covers three districts of the state i.e. East Medinipore, South24 Paragnas, North24 Paragnas. The state has a wide range of mangrove forest in the south portion. Mangrove forest covers the coastal district South24Paragnas. The groundwater quality is different in these three districts. These districts have shallow aquifer system. The quality of groundwater in these districts varies according to their aquifer system. The state has high groundwater reserve, although, the depletion of groundwater is being recognized from 80's in some areas of the state. The significant fall was noticed in both pre and post monsoon period. Coastal zone groundwater faces many hydrogeological problems due to over exploitation, overpumping of water. The seawater intrusion, land subsidence, up coning of water, salinity, sealevel rise etc leads the depletion and retardation of the quality and quantity of groundwater in the coastal regions. The detection of size and extent of problem is important for the any management program. This detection can be done by knowing the quality and composition of the groundwater. Different analytical techniques are used during analysis of sample and they are ion chromatography and isotopes techniques. Ion chromatography is a process that separates ions and molecules based on their affinity to the ion exchanger. It is often used in water analysis and quality control. In hydrology isotopes provides information on the movement and distribution of water in the hydrological system. Water contains environmental isotopes and conclusion may be drawn from their variation. The study of hydrochemical data and information of isotopic ratios provides a figure of the contaminated aquifer that helps in order to evaluate remedial alternatives. The studied data are integrated with GIS techniques and used for the successful implementation of program. GIS helps in the prediction of the future condition of groundwater scenario. Some measures like rainwater harvesting, artificial recharge and many other techniques are used to control the problems of the groundwater in the coastal region. The quantitative understanding of the pattern of movement of seawater into the groundwater and factor that influence these processes are required to manage and maintain the availability and quality of groundwater in the coastal region. The report is divided in the different chapters and they consist of basic information about the groundwater, some literature reviews are included for guidelines and some related work information are also included. In the chapter on methodologies analytical techniques are detailed and the in the result section isotopic and chemical concentration of various analytes and their variations arc detailed. In the management section various mitigation measures to address the coastal hydrological problems to reduce the impacts marine effect in reduction of groundwater resource is addressed. The work presented is useful in general to researchers working in coastal groundwater resources and to field researchers in groundwater problems of West Bengal in particular.