Hopefully this paper will help you:

http://www.currentscience.ac.in/Volumes/101/09/1198.pdf

centrifuging is drawing out those water. Crush it and centrifuge.

Groundwater quantity can be assessed by mapping  of fractured zones in the lava flow, intertrappeans between two lava flows and  depth of Gondwana formation, if the area is falling in Katol/Kalmeshwar  talukas. For more details see our papers publishes in (1) Current science, 2011, 101(9), 1198-1204; (2) Current Science, 2012, 102(1), 61-69; (3) J. Earth System Sciences, 122(1),29-41; (4) J. Applied Hydrology, 2012, XXV(3&4), 85-94; (5) J. Geol. Soc. of India, 2011, 78, 541-548; (6)

@Tharanga Udagedara: I want to find total water available in the area. Your answer is related to some specimen of the rocks water availability.

@Shivendra Nath Rai: According to your answer, water is available between two lava flows but here in area of western Maharashtra place to place the water availability is different and geological pattern also different.    

As pointed out by the previous colleagues that if groundwater is present in significant and economical quantities in a basaltic layer, and then this layer is considered as fractured rock aquifer. Groundwater in these aquifers is present only in fractures and therefore, to quantify groundwater, it is necessary to detect and identify the pattern of farctures and their associated permeability. Despite the fact that VES methods pointed out by Dr.Roemer is a traditional and popular resistivity method, it is time consuming and gives  information below the VES point only and that is why sometimes it  is called “drilling instead of sounding”. For fractured aquifers, I would suggest 2D and 3D Earth resistivity tomography (Please refer to Lock et. al., 1997, 1990, Sherif et al., 2006; Ebraheem et al., 2012 and 2014).

I too agree with the suggestion by Ebraheem that 2D and 3-D Electrical Resistivity Tomograpgy (ERT)is most suitable technique to locate groundwater potential zones in the basaltic Deccan traps. We have used ERT to locate groundwater potential zones in Traps occupied Chandrabhaga basin under Nagpur district, in part of Chiplun Taluk of Ratnagiri district and also in granitic formation in and around Hyderabad city. For more details refer our papers published in Current Science, vol. 102(1), 61-69; J. Geological Society of India, 78, 541-548; Current Science, vol 105(10), 1410-1418

We also used Vertical Electrical Soundings to delineate groundwater potential zones in Deccan trap occupied Chandrabhaga basin. For that  see our papers published in Current Science, 101(9), 1198-1208; Journal of Earth System Sciences, 122(1) ;J. of Applied Hydrology, vol. XXV(3&4), 85-95; j. of Ground Water Research, vol 2/231-42.