An open well is simply a hole in the ground that allows access to water underground. Open wells are used to extract water found at the shallowest level in that area, which are typically found in unconfined shallow aquifers, i.e., soil or rock layers at shallow depths underground, in which water is held without any pressure. Shallow aquifers receive water when rain or other surface water percolates down into the; this process is called recharge. Their water levels rise and fall depending on the amount of water entering or leaving it.
The open well is perhaps the earliest tool invented by mankind to access groundwater. It saved humans from the tyranny of rivers – once open wells were invented, humans no longer needed to live around rivers, and could move inland. They have been used to access groundwater for both domestic and non-domestic purposes; historically, its primary economic use was to draw water for irrigation.
Much of Indian civilisation developed as an “open well” culture. Evidence from Indus Valley sites have shown that wells were common even then, thousands of years ago. The stepwells of Western India – in Gujarat where they are referred to as vavs and Rajasthan where they are called baoris – perhaps best exemplify how open wells have been symbols of culture. Most prominent of these is Rani-ki-vav in Patan, Gujarat, built in 11th century. Designed as an inverted temple to highlight the sanctity of water, this stepwell is now a UNESCO World Heritage site.
Stepwells exemplified the merging of various disciplines like mythology, architecture and hydrogeology. They were also the pinnacles of the art of mass communication. For example, by looking at the level to which the stepwell was submerged, people could tell if the rainfall had been good that year compared to previous years.
Open wells communicate, they talk to you. Unlike tubewells and borewells which were built much later to access groundwater, open wells make it easy to know when summer is close and how to manage water during different seasons. As open wells draw water from shallow aquifers, they are also easily affected by surface pollution, which can be seen in the water quality and is an indicator of when to take action. The well also rewards you for good behaviour. If you recharge it, you can directly see the rise in water levels. Open wells have an implicit culture of sustainability and if we listen to open wells, we will use our water more carefully.
Today, open wells are built with concrete rings, but historically the most common method of construction was using dry stone masonry, i.e. construction with rocks that are not bound together by mortar. Traditionally, water was drawn from openwells manually—most commonly, people used a bucket and pulley, or walked down stepwells to take water directly. There were also devices like the Persian Wheel, a chain of buckets hung around a wheel to lift water up continuously, that were used for irrigation and domestic use. These are still used in parts of India today.
Once the electric pump became the primary means to withdraw well water, it allowed us to “exploit” water in shallow aquifers. This left wells dry in many parts of the country, making us chase deeper sources of groundwater through borewells.
Household open wells used for domestic purposes usually cost far less to construct than deep borewells. When open wells yield clean water, it is much cheaper than borewell water and is a good source for the poor in cities and villages. In many parts of the country, communities draw water from common open wells for free. If maintained properly, open wells can last centuries too. For example, Sarnath in Uttar Pradesh has a 2,300 year-old well that still bears water. You can find more on interesting wells at the public Facebook group Open wells of India and the world.
Bengaluru’s landscape was once dotted with open wells, and some of them are still in use. For example, there are households in Jayanagar, near Lalbagh, that draw water from yielding wells. An open well in the premises of Koramangala police station, another near Jakkur lake, are other examples. A huge open well of 35 ft diameter, along with three borewells, supplies water to the Dhobi Ghat in Vyalikaval, where around one lakh garments are washed daily.
Yielding open wells in Bengaluru had maximum depth of 80 ft only, compared to today’s borewells that are over 1000 ft deep. But open wells have deteriorated with real estate development and neglect, and because of the perception that borewell water is cleaner and long-lasting. In reality, open wells are more susceptible to microbial contamination, but borewell water is more prone to chemical contamination. Contamination of open wells can be prevented by covering them and by protecting them from sewage leaks.
However, as borewell yields have reduced drastically, Bengaluru is seeing a quiet resurgence of open wells. More people are now digging new open wells or restoring old wells, like this apartment builder at Kaikondrahalli. The 40 ft deep well here had been filled up with mud. Now fully excavated, the well has 20 ft of water, and gives over one lakh litres of water daily for the apartment’s use.
When it comes to reviving open wells, Belgaum city leads the way. Belgaum city corporation has revived over 50 abandoned open wells since 1995, when a severe drought crippled its municipal water supply. The revived wells were integrated into the city’s water supply network, and now half the city’s population gets water from these wells at very low cost.
These examples show that it is quite possible for each of us to help fill up our aquifers by digging new open wells, reviving old ones, or by channeling filtered rainwater into wells (recharge). With actions such as these, open wells could yield water even during the harsh summers.