Innovative Rain Water Storage Serves Untka Village Students
“It is impossible to drink the saline water. Every household in Mewat, no matter how poor, calls for a water tanker every month and shells out Rs. 500–600 to have clean drinking water provided to their families. This works out to be very expensive, but it is a necessity here,” said Ahmed, a villager from Untka village in the district of Mewat, Haryana, India.
Very few villages in the district of Mewat have access to fresh water. Most villages’ ground water is comprised of saline. This prohibits villages from using the water for drinking and irrigation. It is estimated that more than 200,000 square kilometers in India are affected by groundwater salinity. The states of Rajasthan, Haryana, Gujarat and Punjab are severely affected by salinity. It is less severe in Uttar Pradesh, Delhi, Madhya Pradesh, Maharashtra, Andhra Pradesh, Karnataka, Bihar and Tamil Nadu. Saline ground water also often contains a high concentration of nitrates, fluorides and lead salts. When this water is consumed, it can lead to many health issues. These health issues include damage to kidneys, bones, eyes and nervous system.
Rainwater harvesting systems can provide villages with access to safe and healthy water. A typical rainwater-harvesting unit captures rainwater and recharges it into the ground. Rainwater is lighter than saline water and thus floats over the saline ground water. Over time, the rainwater spreads out to form a thin layer over the existing saline ground water. The trouble with this system is that it does not provide a method for extracting the rainwater without mixing it with the saline water. To address this issue, Sehgal Foundation has innovated pressurized recharging.
Sehgal Foundation increased the depth and height of recharge wells to below the ground water table and above the ground. This creates hydrostatic pressure (the pressure exerted by a fluid at a given point due to force of gravity). As a result of the hydrostatic pressure, rainwater pushes aside the existing saline ground water to form a sizeable pocket of harvested rainwater within the saline aquifer. The pressure exerted by the surrounding saline ground water keeps the rainwater pocket intact. A hand pump is then used to extract the harvested rainwater from the water pocket formed within the saline aquifer.
Biological contaminants in water are the highest cause of death and disease around the world. To remove them, the water is run through a bio-sand filter. The filter is comprised of four natural filtration stages. These various stages remove biological contaminants and make it safe for drinking.
The Department of Science and Technology for the Indian Government provided Sehgal Foundation with the funds to set up a rainwater-harvesting unit at the Untka government school. It was installed in January 2013 and cost Rs. 300,000. Mohammad Musaraf, a 10-year-old student from the school, said, “We used to drink the water bought by our teachers from a tanker. It used to be dirty. We would go home to drink water and then not come back to school.” Vajika Nazia, another student, added, “We have learned about a new scientific property after seeing this model work on our school premises.”
“The system has made a lot of difference to the quality of education in the school. Attendance of the children has gone up significantly. Midday meals are cooked on time. Before we had this system, children frequently did not get food, as there was no water to cook the meals. It is a boon for our school,” said Hamid Husain, a senior teacher. The pressurized recharge well is very cost effective, as it does not require any additional cost to create a storage structure. This model can be replicated in areas with high ground water salinity and in coastal regions where seawater is a major challenge.
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