September 23, 2019 5:28:11 am
Post recent floods some of villages in Jalandhar’s Shahkot and Kapurthala’s Sultanpur Lodhi have complained that their tubewells are pumping out contaminated and muddy groundwater. While villagers blame highly polluted Chitti Bein, which carries toxic industrial affluent from several cities, for getting flooded and polluting the groundwater source, The Indian Express explains if dirty flood water can get as deep as 300 ft below the earth in such a short period.
How many villages were hit by floods?
In Shahkot, 30 villages and in Sultanpur Lodhi, 20 villages were badly affected where flood water reached 5 to 10 feet and stayed at that level for almost two weeks. In such conditions the tubewells also remained submerged in flood water for weeks.
How many villages are complaining about dirty tubewell water?
Over a dozen villages are complaining about the muddy, contaminated water in both Kapurthala and Jalandhar. Villages located close to Chitti Bein, a highly polluted rivulet, are complaining about brackish water. But at the same time, villages like Jania Chahal, Mundi Chohlian, Nall, Chak Wadala, which were also among worst hit villages and remained under water for a lot period, have not complained about .
Phuman Singh, Sarpanch of Mundi Chohlian, said that while some tubewells in the village were still not functional, others were giving normal water.
“We have government a tubewell at village Nall which was under water for many days, but the colour of water of our tubewell water was totally natural when we ran it after floods,” said Sub Divisional Officer (SDO), Jalandhar, Surinder Singh of Punjab Tubewell Corporation, adding that even two more tubewells of government in other flood-hit villages are pumping out clean water.
How much time it takes for water to permeate to water table level?
The Central Ground Water Board officials in Chandigarh office said water that has stagnated on the surface cannot go deep into earth in just 2-3 weeks and it takes years for water to go deep down at the depth level of tubewells as it first enters the first layer of earth and then it undergoes natural filtration which rids it of several pollutants.
Then why are villages getting dirty water despite the tubewells being 200-300 ft deep?
Experts blame faulty borewells, which have leakages or gaps as likely cause behind the problem that is still under observation. “If 200 to 300 feet tubewells are pumping brackish water it is possible that contaminated water got inside ‘directly’,” said Dr. Rajan Aggarwal, a Senior Research Engineer Department of Soil and Water Engineering Punjab Agriculture University (PAU), and Chief Scientist in All India Coordinated Research Project (AICRP). He added that ‘direct injection’ of contaminated water can happen through faulty deep borewells.
“When a borewell is dug, its diameter is always little bigger than the diameter of the pipe that is to be inserted inside the bore because it helps an easy insertion. But after that the space between the borewell and the pipe must be filled with sand but normally it is left open in large number of cases. Whenever a tubewell gets submerged in any water that water will enter into bore through such leakages/open spaces and can get mixed with available aquifers inside the earth,” said Dr Rajan, adding that a borewells are always deeper than the available aquifers, which can be found at 50 feet, 100 or 200 feet.
Second reason could be that when entire area is flooded and tubewells are too get submerged, the flood water can enter inside the bore well through outlet.
Due to heavy pressure of water through outlet, the filters installed inside borewell pipe can malfunction, thus letting dirty flood water directly enter the earth, which are totally opened beneath the earth, said Sub-Divisional Soil Conservation Officer, Jalandhar, Lupinder Kumar. Such injection of flood water even through a single tubewell can contaminate the entire aquifers of that village or even nearby areas up to few kms depending upon the spread of that aquifer, said Kumar.
Third reason could be that due to collapsing of the borewell or some other leakage in the earth. Experts said that brackish water problem could be temporary or long term depending upon the quantity of such water that directly entered the earth through borewells.
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