Groundwater Geology and Geological Prospecting

Abstract

To explore groundwater in area, the groundwater geology must be well understood by the process of remote sensing, geological mapping, and hydrogeological investigation, and finally, geophysical method is used to delineate subsurface aquifer dispositions horizontally and vertically in a particular geological structure and to assess aquifer property, water quality, etc. Hydrogeological cycle is the process of precipitation, run-off, groundwater flow, evaporation and transpiration. Thus, groundwater is a part of the cycle in the upper lithosphere. It is observed from different studies that sedimentary rocks are most prospective from groundwater point of view compared to igneous and metamorphic formation. Limestone cavities serve as reservoirs for water storage. This is carbonate aquifers. Basaltic lava flows have sometimes been found to be serving as good aquifer. The types of aquifers (confined and unconfined), water table, aquitard, aquiclude, aquifuge, etc., should be well understood for groundwater geology. To determine the aquifer parameters, pumping test should be carried out and storage coefficient and transmissivity are calculated from time–drawdown curve. Hence, it is understood that from geological background, geophysical investigation is done, and on the basis of idea of aquifers, drilling is done. After drilling with the help of geophysical logging, the actual depths of aquifers are known and strainers are fitted. Finally after pump tests, the aquifer characteristics are known and thereby water wells are prepared.