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Rainwater harvesting An alternative to water crisis

A woman collects water from a shallow pool formed on the bank of the River Dhansiri, in Dimapur. In Nagaland, scanty rainfall in the past few months has brought on a drought-like situation as water sources like rivers, lakes, ponds, streams, etc. have almost dried up. Rainwater harvesting is an option that has been increasingly adopted in many areas of the world where the conventional supply system falls short of people’s needs. (Photo/Caisii Mao)


Water plays a very important part in our environment. Without water no living being can survive. It is the life-blood of the environment in which man live and interacts with other living beings. Water has played a unique role in the traditional economy and culture of the native peoples. The availability of adequate and usable water supply underpins our economy; water is used for power generation, waste disposal, recreation, agriculture, domestic use and various other sectors. A sufficient, clean drinking water supply is essential to life but still millions of people throughout the world do not have access to this basic necessity even after decades of work by government and organizations to bring potable water to the poorer people of the world, the situation is still dire. The reasons are many and varied but generally speaking, the poor of the world cannot afford the capital intensive and technically complex conventional water supply systems which are widely promoted by governments and agencies throughout the world.
About 70% of the earth is comprised of water. Yet 2.5% of the world’s water is fresh, of which 0.3% is accessible to us from rivers, lakes and reservoirs. The rest is stored in the most unreachable parts like glaciers, ice sheets and mountain areas. This explains the meager availability of freshwater in relation to the burgeoning demand caused by the huge population growth. Thus the emergence of a sever crisis is apprehended globally. Nearly 1.4 billion of the world’s population lives in regions would face severe water shortages in the first quarter of the new millennium. “These regions do not have sufficient water resources to maintain accepted levels of food production from irrigated agriculture and also do not meet reasonable water needs for domestic, industrial and environmental purposes”. Said the IWMI (International Water Management Institute) in a study completed in 1998. According to UNEP (United Nation Environment Programme), more than 2000 million people would live under conditions of high water stress by the year 2050 and water could prove to be a limiting factor for development in a number of regions in the world. About one-fifth of the world’s population lacks access to safe drinking water and with the present consumption patterns; two out of every three persons on the earth would live in water-stressed conditions by 2025. Around one-third of the world population now lives in countries with moderate to high water stress, where water consumption is more than 10% of the renewable fresh water supply, said the GEO (Global Environmental Outlook) 2000, the UNEP’s millennium report.
According to the researches, some of the world’s most populated regions are losing water, many because of the climate change. The mighty rivers include the Yellow river in Northern China, the Ganges in India, the Niger in West Africa and the Colorado in the Southwestern United States. Aiguo Dai of the National Center for Atmospheric Research in Boulder, Colorado who led the study said, “Reduced runoff in increasing the pressure on fresh water resources in much of the world, especially with more demand for water as population increases”.
In Nagaland, lack of rainfall for the past few months has brought drought like situation as water sources in rivers, lakes, ponds, streams etc have almost dried up. The water shortage has greatly affected the economy of the people living in towns and city as the price of the essential seasonal agriculture product increased due to poor productivity in agricultural sector. Water scarcity has benefited some section of people in the towns as it has become good business, almost all the household buy water everyday. The situation is worst for some section of people who cannot afford to buy water everyday. They burn mid-night oil to fetch a bucket of water or stand in queue for hours to reach their turn. Government is making an a great effort to bring sufficient potable water to the people but it is yet to reach the lower sections people. Many people in the State still lack access to safe drinking water.
Rainwater harvesting is an option that has been increasingly adopted in many areas of the world where conventional supply system falls short of people needs. It is a technique that has been used since antiquity. Infact, rainwater harvesting does not constitute a new technology. It is rather an old technology going popularity in a new way. Rainwater harvesting has been practiced for centuries by people for household, landscape, livestock and agricultural uses. Before large, centralized water supply systems were developed, rainwater was collected from a variety of surfaces-mostly commonly roofs- and store on site in tanks, known as cistern. With the advent of large, reliable community treatment and distribution systems and mare affordable well drilling equipment, rain harvesting systems have been all but forgotten, even though it offers a source of very good quality of water. The modern methods of rainwater harvesting can be broadly categorized under two- i. collection and storage of rainwater for direct use and ii.
Ground water recharging.
Rainwater harvesting is a very simple method and does not require much of scientific knowledge and technical expertise. The underlying principal of the rainwater harvesting is very simple, ‘collect the rainwater when it rains and don’t allow rainwater to run away (runoff)’. It requires simple arrangements for collection (usually through gutters and dropdown pipelines) of rainwater falling on rooftop and storage of collected rainwater for direct use and or for ground water recharge. This method is commonly known as rooftop Rainwater Harvesting. Rainwater falling on the open spaces around the building (other than rooftops) is also used for rainwater harvesting generally by means of groundwater recharging. The following techniques can be adopted to save water going waste through slopes, rivers, rivulets and nalas (i) Rainwater harvesting through gully plugs, (ii) Rainwater harvesting through counter bunds, (iii) Rainwater harvesting through gabion structure, (iv) Rainwater harvesting through check dams/cement plugs/nala bunds, (v) Rainwater harvesting through recharge shafts (vi) Rainwater harvesting through dug well recharge and ground water dams or sub surface dykes. While large sophisticated systems are not cheap, individual citizens can device and use their own rooftop rainwater harvesting system that is effective and affordable. Rainwater catchments system provides a source of soft, high quality water, reduce reliance on wells and other water sources and in many context are cost-effective. Systems can range in size from a simple rain barrel to a more technically sound designed and built system. However, rainwater harvesting systems are inherently simple in form and can often be assembled with readily available material by owner-builders with a basic understanding of plumbing skills.
Some of the advantages of  rainwater harvesting- (i) The never ending exchange of water from the atmosphere to the oceans and back again which is known as the hydrologic cycle is the source of all forms of precipitations and thus of all water. (ii) Rainwater harvesting is a simple concept as the rain harvesting is independent of any centralized system. It promotes self-sufficiency and helps during water crisis. (iii) Rainwater harvesting is not only water conserving, it is also energy conserving since the energy input required to operate a centralized water system designed to treat and pump water over a vast service area is bypassed. (iv) Rainwater harvesting reduces erosion and flooding caused by runoff from impervious cover such as pavement and roofs, as some rain is instantly captured and stored. (v) The major advantage of rainwater over other water sources is that, it is one of the purest sources of water available. It does not contain salts and minerals and it is not subjected to many of the pollutants that often are discharged into surface waters such as rivers and which can contaminate groundwater. However, the purity of rain water depends on where it falls. The rain falling in non-industrialized region can be superior to that in cities and town dominate by industry and automobiles.
Precautionary measures have to be taken before using rain water as the rain comes in contact with the surfaces, it can wash many types of bacteria, molds, algae, protozoa and other contaminants in the cistern. If the rain water is intended for use inside the household, either for potable uses such as drinking or for non-potable uses including showering and toilet flushing, appropriate filtration and disinfection practices are required to be employed. If the rainwater is to be used outside for irrigation, the presence of contaminants is not supposed to be of major concern and thus treatment requirements can be less stringent.
The combination of population growth, climate change, misuse of water, pollution of available water in the 21st century is heading to water crisis. It has become must for every citizen to judicially use water. As the saying goes, “there is no life without water”.
Save water-Save environment-save life.

Soyhunlo Sebu is a Research Scholar in the Deptt. Of Geography & Resource Management at Nagaland University

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