India currently ranks second worldwide in farm output. The country has a total arable land area of 159.7 million hectares and 82.6 million hectares of irrigated crops. Agriculture dominates water use in the country, demanding 83 percent of available fresh sources. This puts tremendous strain on fresh water in India – a challenge set to intensify with population growth, rapid urbanization and climate change.
India is sitting on a wealth of indigenous knowledge and structures that have been – and often still are – in use for quite some time. Setting up dynamic institutions to scale up these interventions and deploy them more widely throughout the country would be a step in the right direction. At present, only eight percent of the rural population has access to treated water in India, and with unpredictable monsoons and climate variability compounded by climate change, polluted and drying water sources, more frequent droughts and floods and high suicide rates among farmers, India could benefit substantially from its indigenous knowledge and structures.
Indian society has a long history of managing water, recognizing and capitalizing on its value for development. In the 12th century, Parakrama Bahu, the Great King of Sri Lanka, advanced agricultural development and ushered in an era of prosperity in the region, overseeing the construction of an unprecedented number of underground canals, tanks and artificial reservoirs for irrigation. The guiding principle under which he took up these works is now a famous quote: “Let not even a drop of rain water go to the sea without benefiting man.”
The dominant climatic feature across most of South Asia is the contrast between the short monsoon season, when rainfall is abundant, and the longer dry season, when water is in short supply. While there are areas that receive more rainfall, they can also become water stressed because of poor management practices. Management is key in ensuring both agriculture and water reserves and managed sustainably.
The southern Indian states of Tamil Nadu, Karnataka and Andhra Pradesh traditionally used tanks to store water. Tamil Nadu does not have perennial rivers, and therefore depends heavily on the rains that come with monsoons, making water storage an important part of maintaining a supply of fresh water year round. These states employed a simple form of engineering, a network of eris, which were either tanks where river water was diverted through earthen channels or standalone tanks fed by the rain. These systems were managed by a neerkatti – a local water manager. Using this principle, historic sites like Vijayanagar and Seringapatam were irrigated by means of diversion dams or anicuts which led to storage tanks. In the river-rich, low-lying, deltaic plains of Bengal and the eastern coastal plains of Orissa, Andhra Pradesh and Tamil Nadu, the agricultural lands were below the river channels. Rice irrigation in these areas depended on flooding, supplemented by diversion canals, storage tanks and by monsoon rainfall.
Wells and earthen dams were the main sources of irrigation in the Deccan Plateau, which covers much of southern India–but diversion weirs with storage structures were also used. Qanats, or horizontal tunnels, a common sight in Iran, can also be found tapping groundwater from hillsides in the Western Ghats mountains.
The Western states of Rajasthan and Gujarat, as well as New Delhi, where water is always scarce, employed a slightly different system involving talabs, or man-made tanks, and architecturally sophisticated structures called baolis, jhalaras, vavs or step wells. During the rainy season, water was diverted from canals into the talabs and then percolated down into the ground recharging a complex of aquifers, raising the water table. Step-wells were five to six storied deep structures comprising a sunken deep cylinder for extracting water and adjacent stone-lined trench with an embedded staircase and side ledges. The latter allowed year round access to ever changing water levels within these wells.
Over in the desert areas of Rajasthan, an indigenous rainwater harvesting structure called taanka was built for each household. The taanka is a cylindrical paved underground pit collecting rainwater with enough capacity to tide over a small family during the dry season. Other arid areas like the Kutch peninsula constructed sloping rubble structures which would intercept water from local runoff. These wells and stone dam structures are called gabarbands.
A number of rectangular embankments were constructed in areas of central India, important for wheat production. In Bihar, these rectangular embankments, known as ahars, would flood from runoff and irrigate low-lying land nearby used to grow rice. Another type of irrigation system, designed by landowners in Maharashtra, was called the phad. It involved a check dam constructed over a river from which a series of canals carry water to the fields. In the fields, excess water is carried into distributaries and field channels via outlets called sandams. Like the phad, khadins are made up of earthen embankments called dhoras built across hill slopes. Surface runoff from the slopes is harvested by khadins which allow for land to be saturated with water. Excess water is drained off by sluices and spillways.
An indigenous version of drip irrigation systems used today, called the bamboo drip irrigation is common in the north-eastern states. Tribes of the Khasi hills use a series of bamboo pipes of varying diameters to carry spring water to their fields saving an estimated 20 liters of water over several kilometers.
Water soak pits or earthen check dams called madakas, pemghara or johads were made by excavating soil in higher elevation areas which naturally bound the structure on three sides while the fourth wall was constructed to hold the water. This is a cost effective way to ensure a replenishment of the water table and to maintain soil-water balance. Another is katta, which is a temporary stone bund made by binding mud and loose boulders. This is often built across small streams retarding the flow of water, enabling some amount to seep into the ground. Dug-wells are a common sight in households along the south-western coast of India.
These indigenous structures and solutions have been used throughout India. With this in mind, ICLEI South Asia set out to rectify the status quo in four Indian Cities under the project Adopting Integrated Urban Water Management in Indian Cities – or AdoptIUWM. Funded by the European Commission, ICLEI enabled the local authorities in the project cities to build their capacity to undertake water sector reforms. Jaisalmer, one of the project cities, which is located in the Western State of Rajasthan, has a series of traditional rainwater harvesting structures and ponds which played an important role in drought mitigation for centuries. Unfortunately these structures and their interconnections are, like other traditional structures in India, deteriorating due to the pressures of urbanization. Through the project, the city, guided by ICLEI, revived Govindsagar, a pond connected to the main city pond called Gadisagar, and an ancient well. Since the intervention, water from the revived pond is being used for green spaces in the city, while the local community utilizes the water from the well to meet their domestic needs.
Channelling ancient wisdom in water management like the City of Jaisalmer can catalyze change towards more sustainable urban water management in the “Cities of the Future”. We should not let it get to the point where claims that the next war will be fought over water actually becomes a reality.