Multistoried Aquifer Studies with the help of Electrical Resistivity in Basaltic Terrain: A Case Study from Dhubdhubi Basin Solapur District, Maharashtra, India.

摘要

Electrical resistivity soundings have been taken in the basin of Dhubdhubi stream, a tributary of Bhima River in the Solapur District, Maharashtra, India. The results of the sounding data revealed two, three and multi layer earth sections. 2 D coverage of the soundings spread over the area facilitated to delineate subsurface interfaces of different layers and qualitative regional correlation between the subsurface geology and electrical resistivity. The electrical resistivity in turn has been used to map possible multistoried aquifers. It is interesting to note that the base of the top layer broadly resembles groundwater surface map, prepared from the observed pre-monsoon water levels in the field. Further, the flow system for second, third and fourth aquifers has also been visualized. It is interesting to note that for the low resistivity (less than 20 ohm-m), for the first aquifer the corresponding transmissivity shows lower values (between 20 to 60 m2 /day). For the resistivity range of 60 to 100 ohm-m, the transmissivity increases and the values are between 120 to 200 m2 / day. This is because of secondary porosity due to fractures. Therefore it is concluded that the secondary porosity plays an important role in the flow of groundwater in basaltic terrain. Thus, the resistivity studies are useful to: (1) delineate flow systems for multistoried aquifer, (2) Planning groundwater development programs and (3) to determine the depth to which artificial recharge is possible and therefore the type of recharge structures can be constructed.