Delineation of Recharge Zones in Drought Prone Medak District of Andhra Pradesh

摘要

Ground water is precious resource of limited extent. In order to ensure a judicious use of groundwater, proper evaluation is required. Aground water development program needs a large volume of multidisciplinary data from various sources. Integrated remote sensing and GIS can provide the appropriate platform for convergent analysis of diverse data sets for decision making in groundwater management and planning. In the present study, an integrated remote sensing and GIS based methodology is developed and tested for the evaluation of groundwater resources. All the information layers haye been integrated through GIS analysis and the criteria for ground water prospective zones mapping and artificial recharge site selection have been defined. For the entire Medak district, an integrated study has been undertaken on the basis of drainage network, surface topography, structural geological features and surface storage sources. Thematic maps for all these aspects have been prepared and overlapped using Geological Information Systems (GIS), to arrive at their inter-relationships in terms of groundwater distribution. The present study has clearly brought about distinct groundwater mounds, signifying areas of potential recharge. High lineament density and good drainage network in these areas of groundwater recharge clearly bring out their contribution to groundwater storage Possible directions of ground water movement have also been indicated in this stud. This information not only significant for visualizing process of groundwater movement during draft in the neighborhood areas of recharge but also on the need for protecting recharge areas from the ground water pollution. The outcome of the study has given clear picture of the areas of excellent to poor recharge zones. The conventional approaches for groundwater investigation are ground based surveys and exploratory drilling which are time consuming and uneconomical. Keeping this in view, the present study attempts to demarcate groundwater potential zones in hard rock areas using an integrated approach of remote sensing, geophysics and GIS. Criteria for GIS analysis have been defined on the basis of ground water conditions and appropriate weight age has been assigned to each information layer according to relative contribution towards the desired output.