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| Not Well Overextraction, contamination and neglect of groundwater and wells affects our water security Now if Panditji decides to go on a well-hunting spree across Kerala, do you know what the count will be? An astounding 4.5 million! Yes, there are about 300 dugwells every square kilometere in the southern most state of India. About 70 to 80 per cent of the people depend on these for household water supply. They have done so for generations. These wells seem to be the perfect source, don’t they? They ensure that the people don’t have to depend on the government for their water. Also, being not more than five to 50 metres deep, they tap shallow aquifers, leaving deeper layers untouched. This is critical in Kerala, which has impermeable lateritic soils that limit natural recharge of deep aquifers. So while the state is known for its heavy and prolonged monsoon rains, very little portion of that actually filters down to restock groundwater.  But, there is a problem here. Now the wells dry up in the 2-3 peak summer months. Why does this happen? Because tradition has given way to technology. Bore wells and tubewells, which suck water from deep aquifers, have led to over withdrawal of groundwater, and a severe depletion in the water table. This is what happens if groundwater is extracted continuously, and not enough attention is paid to ensure adequate recharge: Silting: Sometimes the surrounding sand at the bottom of the well rushes in and fills the well. This restricts the storage capacity of the well considerably. Inland salinity: As more and more water is extracted, the levels of salts like chlorides and fluorides present in the ground rises, contaminating the groundwater. For example, groundwater in most parts of Delhi is contaminated with fluoride and nitrate, and natural arsenic contamination is a major problem in West Bengal. Seawater intrusion: Below the ground, freshwater ‘floats’ above seawater in a delicate balance. Over-extraction of groundwater destroys this balance, and allows seawater to encroach upon or mix with fresh water, leading to either seawater intrusion or upcoming (seeping of seawater into the freshwater table). The Indian people, traditionally, were water-wise. They knew if wells are to remain healthy and functional, steps need to be taken to nurture and feed the water table. Efforts must be made to keep the catchment clear and clean. But as population grew, demand soared, and modern technology intervened, we became increasingly reckless and foolish. Take Kerala as an example. Like in every other state the government here, too, spends, crores in rural drinking water supply built around piped water, handpumps and tubewells. If a portion of this money is spent on harvesting Kerala’s massive rainfall, to recharge the drying aquifers, peak summer shortage could be dealt with effectively.
A well-told story Every well has a history. It also has a reputation, woven into the past. If you know of the tale of any such well, tell Pandit ji about it at panditji@cseindia.org or Centre for Science & Environment, 41 Tughlakabad Institutional Area, New Delhi-110062 Wellopedia 
Dipping in
Drawing water from the depths of the earth is a feat by itself. It requires more than a basic knowledge of physical sciences. But what it requires most is a large dose of innovation and home-grown common sense. Here are some interesting samples of the methods used in various parts of India.  Picota: A wooden beam is placed on a vertical pillar fixed near a well (like a seesaw). A bucket is tied to its one end with a long rope, and the other end is counter balanced with a heavy stone. This method is used in states including Tamil Nadu, Uttar Pradesh, and parts of Bihar. Etram: A wooden pole lever is fulcrumed to a vertical point and a bucket is hung with a pole over the well. A person walks to and fro on the pole and causes the bucket to dip and rise! Another person sitting near the well empties the bucket. It is a common device in southern India. Swing basket: A bucket is suspended with two sets of ropes on each side. Two men stand near the source of water facing each other and swing the bucket to fill the water and then discharge it on the platform on the other side. It is known as ‘iravai koodai’ in Tamil Nadu. 
Archimedean Screw: It consists of a wooden or metal wheel drum with a screw-like interior partition, rotated by a handle fixed to a centre spindle. The spindle projects from both ends and is supported by posts near its ends. The drum is placed at an angle less than 30 degree with its lower end in water. When the handle is turned, the water moves up through the drum and discharges through the upper end. It is used in the deltaic regions of Andhra Pradesh. Rati (Pulley and bucket type): This is simple bucket and pulley arrangement. (The ones you usually see in movies) Mhote Charsa or charas: A large leather or iron bucket is hauled up and down the well by bullock walking on a sloping ramp constructed near the well. One end of the rope is tied to the bucket and the other to the bullock’s yoke. The ropes move over wooden pulleys fixed on the sides of well. It is used in states like Bihar, Uttar Pradesh, Maharashtra and parts of Andhra Pradesh, Karnataka and Tamil Nadu.Persian Wheel (Rahat): Water is lifted in a series of small buckets fixed on an endless belt or ‘strocket chain’ moving on a vertical wheel or drum. Bullocks or camels walking in a circle turn the drum through a set of bevel
gears and shafts, which moves the endless belt. The revolving movement of the belt rises the bucket full of water on one side, and empties it when it reaches the top. It is commonly found in Punjab, Rajasthan, Madhya Pradesh, western UP, and parts of Maharashtra. Pumps: Pumps work on one or more of the principles of atmospheric pressure, centrifugal force, positive displacement and flow caused due to difference of specific weights of the fluid in the columns. |
