A social force called water
MAKE WATER EVERYBODY'S BUSINESS
JUST suppose for a moment, howsoever impossible it may sound: the state just disappears one day. There is nobody to supply you with piped water. What will you do?
Even the idea sounds preposterous at the end of the 20th century. But less than 150 years ago it was the norm. No state in the world supplied water to anybody. And it remains the norm to date in areas such as Nagaland or remote Himalayan villages, where the modern state has failed to reach. Water is not something that anybody can live without. Therefore, people will do everything to ensure their own water supply. And, as technology was once limited, people then depended less on large river systems and underground water sources, They depended mainly on the rain that fell in their towns and villages or on the floodwaters of nearby streams. And people did everything possible to collect this water through household or community efforts.
The last 150 years have seen two major discontinuities occur in water management worldwide. One, the role of the state has grown by leaps and bounds. Two, the state has resorted to increasing exploitation of river water and ground water. The combined result of these two developments, as part of the modern paradigm, has been to destroy the traditional water harvesting systems that were developed using rain and floodwaters through household and community efforts.
Today, it is an open question whether the older paradigm was better than the modern paradigm of water management. A century of water management by the state has shown us the ills that it is capable of.
• One, the state has consistently subsidised water supply, giving the argument that there are many poor people whose water needs must be met as water is a key human need. This subsidy has not meant that the poor have got water but the rich have definitely got into a habit of squandering and polluting water.
• Two, the enormous water demand that has been created as a result has led to over-exploitation of rivers and groundwater reserves.
• Three, not only is there a shortage of water but also a dearth of money to deal with this shortage. The state no longer has the financial resources to invest in mega-projects that can provide the infrastructure to meet the emerging water demand. Subsidies mean such a regular drain on state financial resources that the state neither has enough money to invest in new projects on the scale required nor on the proper maintenance of the existing investments. The result is mayhem both in terms of the quantity and the quality of water supplied by the state. And more and more agencies are saying that the private sector - read private corporations - should be brought into the water business. But the private sector is not just corporations, it also includes individuals, households and urban and rural communities.
So what would happen if you and 1 were to manage our own water needs?
• One, we would have to make all the investments necessary to meet our water needs. In other words, we would meet the full economic costs of our water supply system. Water supply would no longer be a drain on the state's financial resources. The rich would pay money to get their water supply because money is what they have. The poor would contribute their labour because labour is what they can offer.
• Two, as water supply would no longer be unlimited, every body would be relatively more careful -with the use of water. Thus, water conservation would become a popular habit.
• Three, if we allowed our local water resources to become polluted, we ourselves would die of some disease or the other, sooner or later. Therefore, people would slowly learn to oppose pollution and not leave this task to some bureaucracy.
All this sounds like a pipedream. But I am sure with proper education and social mobilisation, this can happen, provided we carefully redefine the role of the state. There is no dearth of experts who talk about the need to reduce state subsidies on water projects, increase water-use efficiency and water conservation practices, and reduce water pollution. To me, all this is possible, but the 21st century challenge lies in developing a new paradigm in which water becomes everybody's business. A paradigm in which the household and the community will enter into a new relationship with the state in water management.
And as this report shows, it is slowly happening in various parts of the world, including India.
This time there will be no divide. The new paradigm will apply not just to poor but also to the rich; not just to rural areas but also to urban areas; and, not just to developing countries but also to industrialised countries. And, in India, we will have so many traditions to learn from.
Indians at the end of the 20th century have a stark choice to make: A land full of water, clean and plenty, or a land thirsty for clean water but only with polluted water in plenty. It is going to be the biggest challenge that the Indian people and their politicians would have ever faced.
The value of a raindrop
After battling both water scarcity and floods, the Sumida City in Tokyo has become a trailblazer in catching and using rainwater
Rain falling in the reservoir area is a must whereas rain falling in the communities is a nuisance, thinks the average person in Tokyo. Makoto Murase, director of urban affairs at Tokyo's Sumida City, is trying to change this.
Japan's capital uses 2 billion tonnes of water each year. The water comes from huge dams built far away in up-stream areas. Tokyo is short of water once every few years. And whenever that happens, it is time for another dam up-stream, leading to displacement and conflict with up-stream communities. At the same time, the 1,500 mm of rainfall it receives each year is not spared a thought. Almost 60 per cent of Tokyo's ground is covered - a city robed in asphalt and concrete. So when the rain falls, the overloaded and overflowing sewage system gives floods. This is the making of an irony of ironies: a parched city prone to floods.
Some 16 years ago, a serious flood inflicted heavy financial and health losses in Sumida City, one of the most densely populated wards in Tokyo. Floodwaters inundated many of the ward's buildings with sewage-contaminated water. For weeks people had no drinking water, as the city's drinking water tanks are installed underground.
The situation piqued Murase, who was then working in the public health centre of the local municipality, to find ways to utilise rainwater. "Rain is an incredibly important resource. It is essential to city planning and to mitigate water shortages, control flood and disasters," says Murase. "But," he laments, "society simply throws it away."
How should it be used? Build numerous mini dams -i-Murase's description of tanks that store rainwater - in cities. This not only reduces the city's water demand and reduces the pressure on water supply but also saves the environment. Large tracts of farm and forest land that large dams devour are also spared.
Moreover, rainwater is free. Its users save money. The civil servant thinks Tokyo is an ideal situation to reap the benefits of collecting rainwater as it is covered in concrete. Being the ideal for numerous cities around the world in terms of industrial development, Tokyo is now setting an example in the use of common sense in collection and utilisation of rainwater.
In the meantime, Sumida City has carried on with innovative measures to use harvest rainwater. Rainwater utilisation policies have been promoted with three aims: developing water resources in communities, restoring the regional natural watercycle, and ensuring water supply for emergencies. The ward office can boast of a rainwater utilisation system that covers half of the building's water needs and saves 1.8 million (us $) 3,500 at present rates).
A major achievement has been the installation of the rainwater harvesting facility at Ryogoku Kokugikan, a well-known Sumo wrestling arena in Tokyo. Rainfall on its 8,400-square metre roof drains into the 1,000-cubic metre storage tank. It is used in the stadium's flush toilets and air-conditioning facilities. About 70 per cent of the facilities at Kokugikan use only rainwater. Sumida City now offers subsidies up to 1 million (us $7,500} per rainwater utilisation project.
Other areas of Tokyo are following suit. A number of local governments in Tokyo, including those of Okinawa Prefecture, Takamatsu City, Toyota City, Kamakura City and Kawaguchi City have started subsidising and loaning funds for installing rainwater harvesting and utilisation systems. About 500 public facilities in Tokyo have already introduced these. The Tokyo dome, a gigantic multipurpose hall which hosts baseball games and concerts, already uses rainwater. Capturing of rainwater is also becoming popular with individual households, which are adopting full-scale rainwater utilisation system.
Along with water has come fame. And as most things Japanese, the fame and the technology has travelled to the US. Even urban planners in New York are showing interest in rainwater harvesting, says Murase. The us-based International Rainwater System Association approached Sumida City to hold a conference on rainwater harvesting. The outcome was the Tokyo International Rainwater Utilisation Conference (TIRUC) held in Sumida City in 1994.
The first conference of its kind, it featured 800 participants and was attended by thousands from across the world. The conference was also the first to focus on rainwater collection and utilisation from an urban perspective, particularly that of the "mega city". It was organised and supported by citizens and funded through the efforts and enthusiasm of people in Sumida City and its neighbouring areas.
After the 1994 conference, Murase has gained the attention of a number of citizens and municipalities. More than 85 local governments have formed a network. Citizens' groups are willing to contribute as well.
In March 1995 after the Great Hanshin earthquake, the organising committee for TIRUC presented 100 rainwater tanks of 200 litre capacity. These were used to store drinking water supplied by wagons to communities in Kobe City. The city's water supply system was totally destroyed by the earthquake.
Rainwater in government policy
In the last week of August 1998, six government ministries and agencies of Japan announced that they will jointly draw up water conservation policies. These will include restrictions on the use of groundwater and promotion of rainwater use. The policies are to be approved by the cabinet by 2000.
The administration wants to curb construction of plants in up-stream areas, prevent deforestation and urban development and discourage the use of groundwater during a water shortage.
The six government outfits involved are: the environment agency, the construction ministry, the national land agency, the health and welfare ministry, the ministry of international trade and industry, and the ministry of agriculture, forestry and fisheries.
They will coordinate policy-making to prevent floods and water shortages in urban areas, among other things. The plans will also promote afforestation and the use of rainwater recycling facilities.
Catching rainwater makes sense even in an industrialised economy. German municipalities have devised a taxation system to encourage it
Situated at the summit of the modern industrialised world, Germany does not lack water. The country is humid and rainfall is plenty. Perennial streams, rivers and lakes are numerous, and groundwater is accessed with ease. Why should it need to capture rainwater? Yet it is doing so.
In 1992 and 1993, water emergency was declared in parts of the state of Hesse. Groundwater levels in the urban areas of Frankfurt fell so low that plants started dying. Lakes and rivers fell dry. Public water supply in Germany is heavily dependent on groundwater reserves. With rivers heavily contaminated by industry and agriculture, groundwater accounts for 72 per cent of the water supply.
There is no tradition of rainwater harvesting in Germany. o But things are changing. Good quality water is difficult to find. Cost of clean water is spiralling at 11 per cent each year, rising much faster than the average cost of living. Collection and utilisation of rainwater is becoming popular.
The average German uses 144 litres of high quality drinking water every day. Only five litres out of this is for drinking and cooking, the rest being used for bathing, cleaning and flushing of toilets, among other things, where water quality requirement is not so high. Efforts are on to find economical ways to substitute 'drinking water1 with 'use water'. On the lines of "low-energy houses", there is an increasing need for "low-water houses".
There are no negative health effects of rainwater, as in the case of other 'use water'. An example of this is refined river water, which people are understandably reluctant to use for purposes of personal hygiene. A 1998 study on 102 rainwater systems for one to four years concluded that in 95 per cent of the cases the bacterial quality was better than the European standard for bath water.
Most rainwater, mainly from roofs and paved surfaces, flows into the sewer. This puts additional pressure on the sewage drainage system and sewage treatment plants, which are at the end of the sewage system. This also adds to the sewage treatment costs. Moreover, in periods of heavy rain the retention capacity of the sewerage is exceeded to unmanageable levels. When this happens, the surplus water has to be released instantly into the river. This is untreated water. It not only it contaminates the river but also leads to floods downstream. The old city of Cologne has been regulary flooded in the recent past due to this. Utilisation of rainwater reduces the amount of rainwater going into the drainage system. Costly expansions can be avoided or deferred. Using rainwater sorts out a range of problems.
Pressure on the drainage system can also be reduced by adding infiltration swales or depressions to the collection system. Unwanted water can overflow into a small pond in the garden, where it can slowly infiltrate into the ground. While the groundwater in the catchment areas is saved by reduced demand, the groundwater level is improved by infiltration.
Thilo Hermann, hydrologist at the University of Hanover, is enthusiastic about this "synergy". He found out from his research that such a combined system, if properly designed, allows more infiltration into the ground as compared to a natural situation.
So why not use this water? The cost of installing rainwater utilisation equipment for a single unit house ranges from Deutche Mark (DM) 5,000 to DM 10,000 (us $2,900 to US $5,800 at present rates). The cost is compensated by the lower water bills, and can be recovered within 10 years.
Cooperation from municipalities
The connection between economy and ecology is increasingly becoming clear, especially in the case of water. In the recent past, German municipalities have started realising the problems connected with the inflow of surface water in the sewer system.
There is an effort to streamline water management. Municipalities have developed a tax system to promote rainwater harvesting. Residents are charged separately on the basis of paved and sealed areas in their houses, such as backyards and drive-ins. A tax inspector measures the paved area roof area to calculate the amount of run-off it will generate. Tax is levied according to this. Since July 1992, there is a levy of DM 1 (us $0.58 at present rates) per cubic metre of freshwater flowing into the sewer. The funds are used to protect groundwater resources.
Residents who have set up a system to catch rainwater or have left the above-mentioned areas unpaved are exempted from the tax. This is a monetary incentive to popularise rainwater harvesting.
The tax works as a lever to motivate people to unseal paved areas and use rainwater. Using the rainwater also lowers the water bills, saving money in the bargain. Facilities to collect water for one's own use are also being encouraged, and do not need official permission. Wherever it is technically and economically feasible, provisions for infiltration of stormwaters are legally binding for new constructions.
With the pressure on house-owners growing steadily, the number of companies offering tanks, pipes, pumps and services for rainwater utilisation is increasing rapidly in anticipation of a lucrative market. Manufacturers and traders of equipment see a business opportunity in this. "The cake is growing slowly, but steadily," says Dietmar Sperfeld, spokesperson for the Association for Rainwater Utilisation, Frankfurt.
Rain, water, and an airport
Frankfurt Airport is the largest in Europe. In 1993, a new terminal was built to cater to 13,000,000 people per year. A new rainwater harvesting concept was developed for the terminal.
The 26,800-square metre roof of the terminal receives 16,000 cubic metres (m3) of rainwater each year. The rainwater is collected in six 100-cubic metre tanks under the ground. It is supplied for cleaning, gardening and flushing toilets.
The plan for the terminal included the supply of 80,000 m3 of refined riverwater, which is unfit for drinking, for the air-conditioning system. The unique project saves 100,000 m3 of drinking water every year. Half the money for the project came from the state. The rest was planned to be recovered by saving the money which the airport would have had to pay in four years for the supply of water.
The summer of 1998 was a wet one. Danes fled to the warmer latitudes to get some sun in their holidays. While they were away, the rain, though unsuitable for sunbathing, was collected in pots, pans, barrels and large storage tanks. Collected to help conserve dwindling drinking water resources.
In recent years, numerous reports have appeared in the media of the contamination of groundwater resources. Bore-wells after bore-wells have been shut down. Contamination with nitrates (from fertilisers), pesticide residues from agriculture and contaminants percolating from waste dump sites is to blame.
Large investments in water treatment plants along with heavy taxing on water consumption helped Danes to understand the seriousness of the problem. From 1987 to 1992, water consumption in Denmark fell by 14 per cent. Moreover, water supply authorities aim to save an additional 20 per cent in the years to come. "That will be a difficult task. But it is necessary if we are to have drinking water enough in the future," says Svend Madsen, head of the water saving department of Copenhagen's waterworks.
In 1990, a small rainwater collecting unit was installed in a house with eight families in the town of Arhus. This has become a popular way for environmentally conscious people to save water. A number of communities now harvest rainwater to flush toilets, wash clothes and cars and for spraying pitches of football stadiums. When not used directly, rainwater is often led from large buildings to small ponds. From here the water can percolate and recharge groundwater.
There are several examples now of catching rainwater in Denmark. Different people use it in different ways:
BO 90, a collective housing complex with 17 flats, collects rainwater in a 10-cubic metre storage facility in the cellar. The water is re-circulated through a separate pipe system for flushing toilets or gardening. The high-quality wastewater of the house - water from the kitchen sink and used bath water - are saved for a cleaning unit. Rainwater is used for washing clothes, points out Erik Jorgensen, a resident. The community was awarded a Scandinavian environmental prize in September 1998.
At a centre with 22 condominiums for elderly people, rainwater is used for toilets and washing clothes.
The 12 toilets at a boy scouts centre use rainwater for flushing toilets, which conserves 225,000 litres of drinking water a year.
The Danish stadium Parken, which hosts national and international soccer games, has since 1993 collected rainwater from the roofs of the stadium. The rainwater is lead to storage tanks that hold 50,000 litres. It is used to water the expensive , pitch of the stadium at night. "We save nearly us $200 each time we use the rainwater. We prefer rainwater to drinking water because the former is soft and poor on calcium, which is better for the grass," says Bent Jensen, technical manager at Parken.
At Rigshospitalet, the main hospital of Denmark, rain-water is used indirectly. Five ponds in central Copenhagen collect water. This is used for the cooling of the hospital's clinics and offices. This provided an alternative to the ozone-depleting chloroflourocarbons in the air-conditioning system.
A car wash facility at one of the major petrol stations along the highway to Copenhagen collects rainwater which is used to wash cars. When the 30,000-litre tank is full, it lasts to about 150 cars being washed in the hall, says Helge Voss of the Danish division of the petrol company Q8s.
Despite these efforts, government agencies and water supply authorities do not believe in these methods. The few rainwater harvesting installations do not have a significant influence on the water use, they claim, adding that the cost of installation does not correspond with the amount of water saved. So there is no support, financial or political. Except an exemption grant on normal wastewater removal and treatment charges.
Collecting rainwater is not the way we are going, says Tina Otterstrom of the Danish Environmental Protection Agency. There are a lot of problems. It requires downscaling of quality measures for water. Though concessions can be made on the quality of rainwater for use in toilets and washing, Otterstrom says that there is a need to ensure that rainwater is not in any way mixed with drinking water. This requires two sets of pipes.
Though the Copenhagen water supply authorities do not promote rainwater harvesting, they recognise that the method has its benefits. It reduces the amount of water coming through the sewers, saving energy use in the sewage treatment plants.
However, disregarding the lack of support from government or municipal authorities, grassroots organisations and communities of environmentally conscious people keep on establishing rainwater harvesting units.
They object to first class drinking water being used for flushing toilets in a world where drinking water is becoming increasingly scarce.
Harvesting rainwater breaches the immense gap between the rich provinces of southern China and the poor northern areas
China's huge water resources look very meagre when compared to its population. The country's per capita water availability is one-fourth of the world average. Moreover, these resources are unevenly distributed both in space and time. South and southwestern China has 81 per cent of the water resources, though it supports only 54.7 per cent of the country's population and merely 35.9 per cent of the land area. Northern China is not so lucky.
"What this means in real terms is that 300 out of 600 Chinese cities lack adequate water supply and 114 have serious water shortage," point out two researchers who have worked on "Rainwater Utilisation as Sustainable Development of Water Resources in China". Zhu Qiang of the Gansu Research Institute for Water Conservancy (GRIWAC), Lanzhou, and Liu Changming of the United Research Centre for Water Problems, Beijing (under the Chinese Academy of Sciences) say that quality of water is another concern. "Tests for the main river section (of the Huang He) indicate that 68 per cent of water samples did not measure up to the national specification of environmental water quality," they indicate.
The conventional way to solve the water crisis has been river valley projects or inter-river basin diversions. With many favourable sites for such projects already used, this is increasingly running into trouble, Zhu and Liu point out. Besides an increasing cost of construction, large projects cause social and environmental havoc, resulting in large-scale inundation of settlements and forests and a negative impact on the hydroiogical and hydro-ecological balances. Over-extraction has lowered the groundwater table considerably.
One ray of hope in this otherwise bleak scenario is rainwater catchment and utilisation in the loess plateau (loess is a special type of soil comprising pale-yellow sedimentary deposits). The plateau and the hilly areas in north and northwest China are the driest and the poorest areas of the country. Both groundwater and run-off are very scarce. The topographic conditions make it impossible to construct water conveyance systems and irrigation networks. Result: 9 out of 10 years are drought years. Poverty is rampant.
The only potential source of water is rainfall. However, rain in this semi-arid area is mostly "small rain", according to the researchers. "It cannot produce run-off on natural soil," they say. Moreover, the deeper soils of the loess are such that most rainfall infiltrates into the soil and then evaporates. This makes for an intriguing situation. Although the Chinese have captured rainwater for about 1,000 years, the harvesting efficiency is too low. But there arc seeds of hope.
Gansu is a very dry province in northwest China. An experiment-and-demonstration programme for catching rainwater has been carried out in the central and eastern parts of the province since 1988. The programme has met with success. About 1,000,000 people in the rural areas have bid farewell to shortages of drinking water after centuries of thirst.
Until recently, the GRIWAC, supported by the local government, carried out systematic experiments on 'rainwater catchment and utilisation' (KWCU). Numerous demonstration projects were set up, aimed at supplying water for drinking and courtyard irrigation.
The new RWCU system comprises a catchment field, water storage and irrigation facilities, Zhu explains. A special kind of cement tile on the roof or a concrete slab in the courtyard forms the catchment field, while an underground cellar stores the water. This has shown to increase rainwater collection efficiency ten-fold. The success of the project has led to the launching of the 1-2-1 programme. This envisages one catchment area feeding two underground storage tanks to support cash and fruit crops on one piece of land. By 1996, about 200,000 families (one million people) had solved their water problem. "The project not only solved the drinking water problem that has puzzled the local inhabitants for generations but also created a better living environment," says Zhu. An additional land area of 10,000 hectare (ha) was irrigated. Yields increases between 20 per cent and 100 per cent were reported.
A follow-up project to improve dry land farming by using rainwater has been carried out on a larger scale in Gansu. Similar projects were started in neighbouring areas such as Ningxia Hui and Inner Mongolia Autonomous Region. In Ningxia, in the autumn of 1995,16,000 water cellars were built to store rainwater for the spring. "In Inner Mongolia, from 1995 to 1996, the pilot projects included 1,584 water cellars built to irrigate 386 ha of land for 1,452 families in 32 villages," Zhu reveals. Water was harvested from highways, threshing yards and also from seepage-controlled fields.
This effort ensured an economical and thoughtful use of the invaluable resource. Land was prepared with furrows to collect more water. It was further covered with plastic sheets to minimise evaporation. An experiment carried out in Ningxia between 1984 and 1995 showed that supplemental irrigation for spring wheat can raise yield by 19 per cent to 29 per cent. Every cubic metre of w r harvested can enhance yield by 2.1 kg.
The city has realised the importance of harvesting rainwater to meet its water shortage. But regulations need to be implemented with greater care
Chennai, the ever-thirsty city notorious for its serpentine water queues, is rediscovering the merits of rainwater harvesting (RWH). It is planning to catch rain where it falls. It is also the first Indian city to include a provision for conserving rainwater in its civic laws. "All special buildings must contain rain water harvesting measures after January 1, 1994," announced the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) in 1993. The Chennai Metro Development Authority (CMDA) suggested a new control rule that included rainwater conservation measures. "The purpose was to recharge the depleting aquifers by rainwater harvesting," says a CMDA official. It would avoid flooding of low-lying areas, a formidable problem in Chennai, he adds.
Water has always been scarce here, often requiring the Metro Water Board to control its supply severely to ensure optimum usage. In Chennai, surface water is drawn from three
inter-connected reservoirs: Poondi, Cholavaram and Redhills (total capacity of 7.152 million cubic metres), white ground-water is tapped from 76 bore-wells located in six well fields of Araniar-Koratallaiyar Basin in the city's north-west.
Situated on India's eastern coast, Chennai has a flat terrain that slopes gradually to the sea. On an average, it receives about 1,200 mm of rainfall, 78 per cent of it during the northeastern monsoon from October to December. The rains are cyclonic - heavy rains in short spells. Most of the rainwater usually flows into the sea.
The 1993 drought paved the path towards RWH. It caused massive water crises all over Chennai. K R Gopinath, a modern-day RWH pioneer, talking about such crises, says, "Rainwater is the trump card for a water revolution, not the major water projects." There were official moves too. The chairperson and managing director (CMD) of the board, M S Srinivasan, suggested that all new building proposals should include a RWH plan. In 1994, the new CMD, Shantha Sheela Nair, took up the matter. Later, private builders became enthusiastic about RWH, and in 1997, a forum of builders met the CMD, and decided on the types of RWH methods to be adopted. The board also published a brochure, suggesting various RWH methods.
The concept of rainwater harvesting has been accepted by the builders and many have even improved on the existing methods. However, there are problems. R Kumar of Navin builders says, "Most of the builders are doing RWH, but the government is yet to implement the order in their own buildings." T K Ramkumar of Exnora International, non-governmental organisation (NGO), criticises the government for its soft approach. "There is no serious attempt to implement the decision. People don't seem to understand the potential of rainwater," he says. N V Fundarikanthan, former director, Central Water Resources, Anna University, Chennai, says, "Now that the issue of water conservation has been raised, the government should plan seriously and implement RWH in a big way." In the absence of a systemic approach, RWH move might soon lose steam, the experts fear.
The Rotary Club of Madras recently revived three temple tanks in their attempts to cure the city of its water scarcity. But it is not enough. Once Chennai could boast of 39 temple tanks
or kulams, each with an area of one to seven acres. These not only trapped rainwater but acted as flood-control devices and recharged the groundwater sources as well. Urbanisation, however, made these tanks obsolete, almost reducing them to garbage dumps.
The Virubhaksheeswarar, Gangadeeshwarar and Rawees-warar tanks in Chennai suburbs were recently rejuvenated, thanks to the club, which had taken up the initiative in the early 1990s. R Benjamin Cherian, a rotarian, says, "We wanted to revive the tanks as they would recharge the ground water." The tanks are designed in an attractive, artistic manner. During some festivals, the idol of the temple deity is taken to the centre of the tanks.
Due to Chennai's topography - it slopes from west to east - major inlets have been built on the tanks' southwestern or northwestern corners. Further, they were interconnected to drain the overflow of one into the other.
However, maintaining these tanks is a problem. The Temple Authority is severely cash-strapped. So the Rotary Club came to the rescue again. Interacting with schools, the club would have groups of school children visit the tanks and clean them on every holiday. "People living in the neighbourhood have also come forward for the maintenance," says V Ganesan, who is involved with the project. The Rotarians are optimistic, and are planning to revive three more tanks this year.
R Jeyakumar promises 72 crore litres of water to Chennai annually. But he is neither a water-diviner, nor a magician. He is a builder. So how does he plan to quench Chennai's perpetual thirst? "Very simple," he says, "Catch the rain water." His method of collecting water from within house compounds can help solve Chennai's water problem.
A drain, dug along the compound wall, collects the run-off during the rains. The excess water that flows along the drain would be fed into a series of bore pits connected to the drain though pipes. The water then would reach groundwater aquifers, recharging them.
Jeyakumar's 44-year-old mind makes some quick calculations: Assuming, one bore pit fetches 600 litres a day, 10 pits per house would trap as much as 6000 litres. And assuming there are 60 days of rain annually, the total water conserved per house is a huge 3,60,000 litres per annum. Taking a target of 2,000 house, the total rainwater collected in Chennai would be 72 crore litres.
The substantial rain that this state receives runs off due to the hilly terrain.
But the state government is realising the importance of catching this
Mizoram is blessed with a lot of rain, 2,500 mm per year. Yet this tiny north-eastern hill state invariably faces acute water crises in the dry season.
The reason is the topography - hills of sedimentary rocks comprising mostly of hard shales. The run-off disappears fast. Though this run-off gives rise to springs in the rainy season, they disappear soon. There has been a tradition of collecting rainwater to make nature's bounty last over the dry months.
Rainwater is harvested widely in the region. It is gaining popularity, especially in the rural areas, where piped water supply remains inadequate and expensive.
The towns of Mizoram are located on hill-tops or on the upper reaches of slopes. Water from rivers has to be lifted up to these towns. Aizwal, the state capital, has a public water supply system based on water from a perennial river called Tlawng. It is designed to supply water for a population of 80,000. However, the population of the city now exceeds 300,000. Rainwater harvesting has continued to play a very important role here.
Today, Aizwal meets most of its water needs from roof-top rainwater harvesting. Townsfolk try to meet their water needs without depending on municipal supply. And this entire effort was undertaken by the people themselves with no government support.
Mizo villages were established on hilltops to protect against marauding tribes. They used springs for their water needs. Rainwater percolating in the soil on the hill slopes comes out in springs at outcrops of rock layers during the rainy seasons and many weeks after rainfall.
Small catchment tanks were constructed with stone masonry or concrete masonry at convinient locations and the water collected in these catchment tanks was an important source of water supply. At some locations water from such catchments was available throughout the year.
However, spring water became inadequate as Aizwal grew. The springs also began to dry up, largely due to deforestation. Government had to haul up water from rivers and streams miles below the town. The cost was enormous, the supply scanty. Moreover, the water had chemicals and bacterial contamination.
History came to the rescue. In 1894, the British established the first administrative unit here. Water was supplied to the British post from a 5,455,200-litre underground rainwater reservoir. This was fed by a catchment of sloped roof with galvanised corrugated sheets around the reservoir.
Roofs of buildings in Aizwal are sloped keeping with the wet climate. Roof-top rainwater collection is thus the most convenient and economical form of water supply. Households slowly turned to roof-top rainwater harvesting without help from the government. Rainwater in Mizoram is quite pure, the region being virtually pollution-free.
Yet, roof-top harvesting is losing some of its mystique in the urban areas due to subsidised piped water supply. Further, the region has also witnessed a rise in the use of modern toilets and kitchens. Using rainwater in these is highly inconvenient.
However, the future of roof-top harvesting in the modern, urbanised areas is not overtly bleak. The government is slowly recognising the need for it, encouraging it by underwriting the cost of construction of rainwater harvesting units. In the rural areas, about 6,000 private systems have been set up owing to this effort.
Written by Anupama Kumarfrom reports by Makoto Murase and Nobua Kurokawa in japan, Hannah Buttner and Uwe Hoering in Germany, Gert Lynge Sorensen in Denmark, Zhu Qiang and Liu Changming in China, John Mbugua in Kenya, Jitendra Verma in Chennai and Dunglena in Mizoram