Water scarcity is a part of daily life in the quasi-desert state of Gujarat, and its largest city, Ahmedabad. With the city experiencing hyper growth, the tremendous pressure on its infrastructure is in-your-face, and groundwater tables have been falling at the rate of 2-3 meters per year because 70-80% of the city’s water supply has come from borewells. Those can be seen all along the road even today that additional water is carried in through canals from the distant Narmada river, some 200 km away. In spite of this, the daily water supply per capita today is a mere 140 litres (as opposed to 180 litres envisioned by the city ’s water plan about ten years ago). From the policy side, the city has adopted some new water regulations after a major drought hit the state of Gujarat in 1999. It now mandates that all new developments above a certain size to either capture rainwater for direct use, or to collect it in a percolation pond for filtration and much-needed recharge of the ground water.
In fact, several interesting layers of sophisticated water management infrastructures from different times in history can be traced underneath the organic urban structure in the dense old city of Ahmedabad. Its distribution network dates back from colonial times. Integrated in the old town’s community-based spatial morphology of ‘pols’, different sized neighborhoods organized around semi-public courtyards, is a system of fresh water supply and sewage pipes that cater to each house. It lies beneath the street surface, but is made legible by tall poles, indicating the location of the pipes and direction of the water flow.
Ahmedabad also has a long history of rainwater harvesting. The oldest example for this are the famous vavs, the monumental step wells that used to provide rainwater, collected during monsoon season, to the community year-round. These structures are multi-storey underground water tanks shaped such that a series of stairs, on one side, would allow for comfortable access to the water level as it is slowly falling over the course of the dry season, while there is also a direct connection to the lowest point of the well from where water can be pulled up to the surface in a vessel. The step wells are adorned with artfully carved pillars and arches, and the climate inside is cool and pleasant. Examples of step wells that still exist today in Ahmedabad include Dada Hari Vav and Adalaj Vav, both built in the 16th century, as well as Mata Bhavari Vav, which is even older. What is interesting is that places of worship (both Hindu and Muslim) are either integrated in each of the vavs or can be found directly adjacent. Those, today, are still in use while the wells themselves have dried up.
The traditional wooden residential structures as well as many of the places of worship of the Old City incorporate a smaller scale version of rainwater harvesting. Water used to be captured from the second rainfall of the monsoon onwards, from the pitched roofs, then carried down through copper gutters and chains to be stored in limestone-lined deep tubewells (between 30 and 50 ft deep at 2-3 ft in diameter). The relatively small scale (25.000 – 30.000 litres per family and year) of the wells implies that this water was used mainly for drinking and cooking. The use of copper and limestone as materials ensures the high quality of the water to last for months; it is in fact far superior to the quality of water from other sources, including today’s municipal water supply. Maintenance and operation efforts, given the simplicity of the historic structures and durability of materials, are relatively low.
Since the construction of a large scale municipal water supply system, however, most of these rainwater harvesting systems, much like the step wells, have fallen idle. Interestingly, though, Nirav Panchal of the Heritage Project of the Municipal Corporation of Ahmedabad has explained to me that people have been approaching the city in the past five years in search of advice as to rehabilitate their rainwater harvesting structures for daily use .
Why would people want to do that? It improves their quality of life very directly by providing for the safest, healthiest, and best tasting drinking water one may hope for, and it is reliable in the long term (a tubewell fills up with two or three good rains).
The most important thing for the city remains the combined impact of many, many micro scale systems
This highlights the role culture and awareness play not only for rainwater harvesting, but also for water conservation and grey water re-use, and ultimately for the water safety of the city. What shapes the water problems of entire regions, according to Prof. C.N. Ray of CEPT University in Ahmedabad, is the mentality brought towards the matter by people. He argues that this is why coping mechanisms have traditionally been more sophisticated, and per capita demand has been much lower, in areas that have historically experienced water scarcity, such as Gujarat, than in those with more plentiful water supply. It is incredibly important to harness what remains of the pre-’near-unlimited-water-from-the-tab’ mentality. Thas means to embrace the idea to restore historical systems, and even to construct new mechanisms for rainwater harvesting at a household or small community scale. The traditional example shows how simple this is provided some basic design parameters are taken into account.
Now imagine this happening citywide. The simple collection and storage of rainwater from roofs could contribute about 10% to the freshwater supply, while also improving public health. Especially if combined with a similar system of grey water re-use, this could dramatically reduce the per capita use of tap water, and make for a much more sustainable growth. Not only in Ahmedabad, but also in other cities and even countries.
