RAINWATER HARVESTING: IMPACT ON SOCIETY, ECONOMY & ECOLOGY ABSTRACT

Transcription

1 RAINWATER HARVESTING: IMPACT ON SOCIETY, ECONOMY & ECOLOGY Radha R. Goyal 1 and Bharat Bhushan 2 1 Research Scholar, Dept. of Civil Engineering, IIT Delhi, Hauz Khas, N. Delhi Senior Engineer, Triune Projects, New Delhi ABSTRACT A sufficient, clean drinking water supply is essential to life but millions of people throughout the world do not have access to this basic necessity. Even after the intensive efforts of Engineers, Planners, Builders, Governmental and Non Governmental Organizations (NGOs) to bring potable water to the poorer people of the world, the situation is still dire. There could be various reasons for that for e.g. Cost, Climate, Technology, Hydrology, Social and Political reasons. In developing world like India, Sri Lanka, Kenya, China, Thailand, Tanzania, where the hundreds of millions of people depends on rainwater for their domestic water needs and rain is not a regular phenomenon throughout the year, rainwater harvesting (RWH) is the only possible choice, which can solve their problem of water scarcity but unfortunately it is often overlooked by planners, engineers and builders due to lack of information. It has been estimated that almost 25-35% of total rainwater is lost in the form of surface run-off and causes flooding in downstream areas and soil erosion. Conserving this water will not only solve the problem of water shortage for their crop production and other household needs but it will also reduce soil erosion and protect the environment. Surface tanks, "pathaha (recharging structures), wells, bore holes etc. are some of the commonly used traditional methods in dry areas. Although domestic roof water harvesting (DRWH) is also in practice in many countries in two forms, namely, Informal DRWH and Formal DRWH, but are used rarely on a significant scale due to either they produce a small amounts of not-very-clean water or adopted with subsidies, which can t be afforded by poor households in villages. So there is a need of development and assessment of very low cost domestic roof water harvesting (VLC DRWH) technologies, which can meet the water needs of poor households in developing countries. In order to assess the potential for a considerable expansion of DRWH usage by the poor, we have to ascertain the underlying economic viability of this mode and understand impediments to its use. We have to demonstrate how far it can give potable, reliable and of course affordable water. This paper includes the existing technologies, available for harvesting the water, which are either capital intensive (economically not viable) or technically complex and are environmentally and socially inappropriate, along with the new technological alternatives and their social (such as gender issues influencing the adoption and use of rainwater harvesting systems), ecological

2 (effect on local biodiversity and crop production, ground water levels and soil erosion) and economic (such as willingness to pay, seasonal variations in water costs etc.) implications. The better rainwater harvesting practices/ technologies, which are driven by a clear understanding of the specification, can conserve the biodiversity in home gardens by promotion of agro forestry systems. INTRODUCTION India gets approximately 4000 billion cubic meters (BCM) of water every year from all natural sources. Out of this 700 BCM are lost in evaporation and another 700 are lost during the flow on ground. Also, the large part of water namely 1500 BCM flows into the sea due to floods. Thus, the remaining available water is only 1100 BCM. Out of this ground water recharge accounts for 430 BCM per year and the present utilized surface water is 370 BCM. The balance-unutilized water, which can be harnessed, is 300 BCM. Flood normally affects, 8 major river valleys spread over 40 million hectares of area in the entire country affecting nearly 260 million people. Similarly the drought affects 86 million people who are spread in 14 States covering a total of 116 districts. Wherefrom this flood comes? It comes from the 1500 BCM of water every year flowing during the monsoon season (water convention 2005). If we have to prevent the damage due to the flood and reduce the severity of drought, we have to harness this 1500 BCM of water and distribute it to the drought-affected areas. We can also partly store it in proper storage system so that it can be available during non-monsoon months. If we succeed in doing all these, we will not only save the loss arising out of the damage caused to the crops, properties and people by the flood to the extent of Rs crores on an average per year, we will also save the recurring expenditure of Rs crores incurred by the government as short term relief measure. Now the questions arise are how to harness the floodwater and how to regulate the out flow of floodwater? So that, it does not go into sea or does not simply get evaporated. It needs to be converted into useful water for the mankind. Rain Water Harvesting (RWH) could be one of the ways to answer these questions. Our ancient history tells that many individuals and groups/ communities/ societies have taken the initiatives to develop a wide variety of different RWH systems throughout the world. These systems were developed either with the aim to meet the water needs of communities (rural/ urban) or individual households. The various RWH systems developed were in form of dams, digging holes, reservoirs, under ground /above the ground tanks, watersheds/ catchments, desilt ponds, rivers, recharge wells etc. Though, there are number of methods/ techniques available but their cost, climate, technology, hydrology, social and political elements play an important role in the eventual adoption/ implementation of these methods; and unfortunately those points are overlooked by our planners, engineers and builders. As a result, the systems get fail. The main reason for this is simply the inadequate or lack of information (not easily accessible) both technical and otherwise. Therefore, there is a need to improve understanding of the above-mentioned factors to improve performance of RWH systems on small scale (households) as well as on large scale (community/ town). Out of the above-mentioned factors, I would like to give emphasis on effects of various RWH systems on the three major factors, namely social, economical and ecological factors.

3 RAINWATER HARVESTING TECHNIQUES Domestic Rainwater harvesting (DRWH) systems Roof water harvesting (RWH) is an option, which has been adopted in many areas of the world where conventional water supply systems have failed to meet the needs of the people. It is a technique, which has been used since antiquity and examples of RWH systems can be found in all the great civilizations throughout history. This technology can be as simple or as complex as required. Traditionally, in Uganda and in Sri Lanka rainwater is collected from trees, using banana leaves or stems as temporary gutters; up to 200 litres may be collected from a large tree in a single storm. With the growth in corrugated iron roofing in many developing countries, people often place a small container under their leaves to collect falling water during a storm. Whereas, in modern Indian cities, underground storage structures are made and water from rooftops is led into these structures. This stored is generally used for non-potable purposes (flushing/ gardening etc.) In more sophisticated ways, filters are used, which are made of sponge and a mixture of sand, gravel and charcoal. After first flushing and filtration, water is led into under ground sumps (which are very common in Bangalore) or to a new storage tank. The overflow from this tank is taken to an open well to recharge the aquifer. Benefits: it provides an innovative solution to meeting water needs and can be implemented quickly and modularly. It is also very robust against risks of unexpected change such as aquifers dropping or becoming polluted. It is decentralized system and independent of topography and geology. They deliver water directly to the household and relieving the burden from women and children of carrying water from kilometers of the nearest clean water source, especially in rural areas. Implementation is similar to managing the installation of on-site sanitation and once systems are in-place, they are owned by the householders who can then manage their own water supply. This method is best of use in area, where groundwater in high-risk/ wells could fail and sources are limited. In spite the benefits, it also has certain drawbacks as high cost, uncertain quality, difficulty in implementation and lack of knowledge. So it is worth bearing in mind that domestic roof water harvesting (DRWH) is not the definitive answer to household water problems. It can be the solution after the improvement in technology and to making this to be very low cost (VLC). Community based rainwater-harvesting systems Community-based rainwater harvesting is the paradigm of the past. Small check dams, earthen check dams (Johads), long channels leading to lakes (Choukhas), jheels (shallow wells dug in low depressions particularly in Kutch area- Gujarat), dongs (ponds made by tribes of Assam for irrigation)) and nullah bunding are some of the community- based traditional techniques, which are still in practice in rural India. The community approach is the most effective way of implementing RWH systems especially in drought prone villages of India. A survey conducted by CSE of several villages facing drought in Rajasthan, Gujarat and western Madhya Pradesh in December 2004, found that all those villages that had undertaken rainwater harvesting or watershed development in earlier years had no drinking water problems and even had some water to irrigate their crops. Few examples of successes of community-based rainwater harvesting systems in India are given below. Rajasthan- A Success story of traditional community- based rainwater-harvesting system Johads are small earthen check dams that capture and conserve rainwater, improving percolation and groundwater recharge. Starting 1984, the last sixteen years have seen the revival of some 3000 Johads spread across more than 650 villages in Alwar district, Rajasthan.

4 The Bhaonta village in Alwar district of Rajasthan named the nation's 'most outstanding environmental community' and recipient of the Joseph C John award for the year 2000 for its community's efforts at rainwater harvesting and forest protection. The Johads, or small earthen dams designed to capture and conserve rainwater, and a series of anicuts (small concrete dams) built by the local community with the support from Tarun Bharat Sangh (TBS), an Alwar-based NGO and Gram Vikas Navyuvak Mandal Laporiya (GVNML), a Jaipur- based NGO. This has resulted in a general rise of the groundwater level by almost 6 meters and a 33 percent increase in the forest cover in the area. Therefore the local ingenuity, indigenous knowledge-and pride-of the villagers have regenerated forests of Bhaonta, where the more elaborate and costly structures built by expert engineers have typically failed. The Samara village on the banks of the river Arvari, where villagers pointed out that even after three consecutive years of low rainfall, the village wells did not go dry. This was due to the Arvari catchment area that has recharged the groundwater and has revived an endangered Arvari river. With encouragement from the founder of CSE, the late Anil Agarwal and TBS, 70 villages in the Arvari catchment areas joined forces to create the Arvari Sansad, or Arvaric 'Parliament', to manage the endangered river and its water and four more rivers in that area, which used to go dry immediately following the monsoon have now become perennial. Gopalpura was the first village of Alwar district, where TBS first intervened the water harvesting - a series of Johads and the village community protected their lush green forests with the believe that the local control of water was a formidable weapon in the battle against poverty. In the Neemi village of Jaipur district, the water harvesting efforts supported by TBS has changed the fate of the village by improving the village's economic, social and environmental health. Improved food production in the village now attracts laborers from outside. Choukha systems are long channels leading to the lakes are built to increase the catchment areas of the adjacent talabs (village ponds). The earthen bunds are made that collect and store rainwater. During rainfall, excess water from one Chouka, drains to the adjoining Chouka, and so on, until finally flowing into the monsoon drain. Small dug pits in the choukhas facilitate groundwater recharge. This simple water harvesting method is good for open pasturelands and imposes fewer restrictions on open grazing. Sitapura village in Tonk district of Rajasthan is the site of a four-year conflict over pastureland encroachments between the community on one side and local power interests represented by the village elites and a sympathetic panchayat on the other. After the recent success of community against local elite interests, the village community has decided to develop their pastureland into choukhas. The village has started rainwater harvesting to tackle groundwater salinity. On the other hand, a water harvesting built on the roof of the village school ensures students now have access to plentiful supply of filtered water. These two case studies of rural Rajasthan shows that the small step for water harvesting has the potential to alter the economic, social and ecological terrain of rural India. Drinking water is available throughout the year in the village. Women joyfully narrated as they relieved from carrying water from long distances of clean water sources. The revival of the river has transformed the ecology of the place and the lives of the people living along its banks. Their relationship with their natural environment has been strengthened. It has proved that how rainwater harvesting has strengthened local communities to work collectively for development? It helps in realizing people that humankind is not the master of the environment, but a part of it. If human beings put in an effort, the damage caused by us can be undone. GUJARAT- A Success story of traditional community- based rainwater-harvesting system The community has taken the initiatives of reviving several local rivers and rivulets in the tribal regions of rural Gujarat (Villages of Dahod, Patan, Surendernagar and Rajkot districts). One such river is Kali-II, which is approximately 35 kilometers (km) long and with a catchment area of 24,000 hectares. The river has become perennial due to the construction of a series of eight check dams at appropriate distances across the entire length of the river. It has made the fields of village lush green and enough water is available for drinking as well as irrigation purposes, which

5 made it difficult to believe that the area rained below average in year 2001 for the third consecutive year. It shows a healthy mix of engineering skills and community participation has unleashed ecological, economic and social transformation in the village. Agriculture is flourishing in the villages, where earlier there was not enough water to drink. To enhance their economic benefits, the villagers have installed lift irrigation system, which is managed by the community. Every user has to pay Rs 25 per hour for irrigating their fields. Madhya Pradesh (MP)- A success story of traditional community- based rainwaterharvesting system In Madhya Pradesh, the social mobilization programmes - Rajiv Gandhi Watershed Development Mission (RGWDM) and Paani Roko Abhiyan (PRA) sponsored by government encouraged people to construct the two stone masonry structures on a seasonal river, Modh. These works have been done with community s contribution and have the annual potential of irrigating 90 per cent of the village fields. The success of these programmes shows that the water command is the common bond in uniting people, irrespective of their socio-economic backgrounds. The pioneers of these technologies are the people who never went to Indian Institutes of Technology to try and do quantum physics, or genome or defense research in the US for the US. They are invisible rural engineers who prefer to find the ways to better harvest the rain in their own way. And so fashion local ecological and social change. All of them have developed watersheds as a platform for social change. Traditional rainwater harvesting systems in urban India - after taking into consideration the rainfall pattern and availability of water resources, artificial recharging of aquifers through dug wells/ bore holes and roof water harvesting are found to be the best methods for solving the water scarcity problem in urban areas. Community and household management had primacy over state supply of water. So every household has a role to play in catching rain and harvest every drop of water, which is falling. After looking into various traditional rainwater harvesting technological alternatives, I can confidently state that there is tremendous potential of India's traditional water harvesting systems but for exploiting this potential we have to make water everybody's business and put the community-based water harvesting in national agenda. This community- based approach has much strength in today s time as it had ever before. It resolves many social issues and enable to enhance the people's capacities to assess the situation and examine possibilities for addressing drought more constructively and organize themselves into groups to tackle the problem collectively. It also takes away people from dependency frame of mind, which often created by government systems. It reduces the risk of disaster by building the capacity and also enhances the livelihood security. It will put a check on protests, demonstrations, road-blockades, riots of city-dwellers against farmers, villages against towns, towns against cities, citizens against the government, and people against people. Similarly, it also handles various economical as well as environmental issues such as willingness to pay, extent of 'informal' RWH, seasonal variations in water costs, cost of design of RWH structures, environmental degradation, health effects of water borne diseases etc. It improves agriculture, forest covers, and so the animal husbandry and the ecology For successful implementation of community-based systems of rainwater harvesting, the following approach is followed.

6 Building the water literate society. Studying the gravity and extent of the problem of drought in selected areas. Researching the livelihoods of people living under conditions of drought Identifying the availability of resources in the locality Analyzing community risks and needs in a participatory process that takes people's perceptions into account Defining the role communities already play in drought preparedness and management Exploring ways to strengthen the community's ability to deal with drought more effectively - building on indigenous knowledge and reviving traditional disaster coping methods Discussing the situation of the community with local government institutions and development organizations Identifying "structural" and "non-structural" risk reduction strategies that are based on local conditions and felt needs Enhancing livelihood opportunities for communities by sharing information on relevant technologies Realizing the importance of RWH, the Central Ground Water Board (CGWB) is taking steps for encouraging people to recharge groundwater through rainwater harvesting in their city. Almost all state governments are making some laws to implement RWH in all the new structures and promoting community- based programmes on RWH. All the efforts are being made to meet the water demands of the country, which is the most important paradigm of its development BIBLIOGRAPHY 1. National Water Convention, 2005, Inaugural speech by President of India, Dr. Abdul Kalam. 2. Pani Yatra, December 2004, Centre for Science & Environment (CSE), New Delhi, India. 3. Current rural water security practices with DRWH, Lanka Rainwater Harvesting Forum, March Agarwal Anil, India s traditional rainwater harvesting systems, Dyeing Wisdom, Pub. by Centre for Science & Environment (CSE), New Delhi, India.