Mystery of Underground Water - a talk by Dr. Mahesha, Geologist
Post date: Mar 20, 2017 3:29:34 PM
In recognition of the world water day on 22 March 2017, a technical talk was organized at Nesara premises on the geological aspects of WaterWater has always remained life's elixir and as we face drought for yet another year, we dig deeper into earth searching for water. Lakhs of bore-well are dug with no perception of the effect this rigging of the earth has on our surface water. Mahesha.V, retired Deputy Director of Ground Water Wing, Dept of Mines & Geology, spoke on the effect of bore-wells and the inter-relatedness of water sources. Life has evolved and flourished and continues to exist on the Earth only because of water. This fact has been recognised in Vedas itself in Mantrapushpa. The water cycle consisting of water vapour, clouds and rains, ice and glaciers, surface run-off, seeped water underground and all these going back into the sea is one of the most fascinating phenomenon of Mother Earth. With the advent of the human beings on earth, the exploration and exploitation of surface and ground water was started by way of digging pits in sand beds, followed by digging wells on slopes and most importantly through bore-wells in the last century and by construction of micro and macro storage structures (ponds, tanks, dams etc) across the streams and rivers. In the process, the natural water flow system has been impaired beyond compare!
Karnataka State consists of only hard rocks of ancient origin in which ground water occurs mostly in fracture and joint systems and forms just about one percent. Earlier to the advent of bore-wells in the year 1965-70, groundwater was extracted only through shallow dug wells for all potable and non-potable uses. Their number was just about one lakh. Most of them had either limited water or dried up during summer depending on the rainfall pattern in the respective years and change in the water table conditions in its natural state. All this has changed after the proving of bore-wells as a source of continuous water extraction during the years 1966-75. The absence of restriction by law resulted in a free for all. Bore-wells were constructed by fast rigs in lakhs during the last 45 years competitively reaching deep and deeper depths.
This resulted in a devastating effect on the water cycle, because the bore-wells pierced through the natural flow system in which the groundwater existed in our rocks since millions of years. The bore-wells became vertical conduits for the free flow of water from shallow zones to deeper zones of not only ground water but even rainwater and other surface waters. The ground water held under natural pressure came out as springs in earlier stages when bore-wells were drilled from the bottom of old dug wells. But as the density of bore-wells increased in individual areas, it had a tell-tale effect on water table conditions and gradually the age old shallow dug wells dried up followed by deeper dug wells, shallow bore-wells and deep and deeper bore-wells too. It has a cascading effect on surface water bodies too, starting from small ponds and M.I tanks in high bore-well density area, where the natural streams started going dry with limited or nil inflow into man made water holding structures. The effluent character of many streams that existed since millions of years changed to influent and it started extending from minor streams to major rivers (Vedvati River in Chitradurga is a classic example). Thousands of natural water springs dried up. The free flow of groundwater induced by bore-wells coupled with industrial wastes, human waste, artificial manures, disinfectants, pesticides and faster solution activity in the rocks has wrought havoc on the quality of both surface and groundwater. The natural water cycle in existence since thousands (millions?) of years has been disrupted in the last few centuries and especially during the last century. Unless a concerted effort is made by all the human beings without boundaries, the future may prove to be very bleak for all types of water users.
Dr. Mahesha was also critical about the underground sewerage system as it pollutes the underground water badly and he questioned the current Government's push for one toiler for one house, which may not be appropriate for Indian context.