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Rain water harvesting for
sustainable social and economic development

Sri Lanka’s three decades of conflict leaves the Northern and Eastern provinces most affected, with infrastructure and institutions non-functional, homesteads in disrepair, livelihoods destroyed and most people unsettled and many traumatised. Now since the war is over and people and the land is free from the clutches of the terrorist, battle is now on to rebuild the infrastructure and the homes, resuscitate the institutions, resettle and rehabilitate the affected and displaced people and help them redevelop their livelihoods.

It is only through social and economic development in these areas and people we can hope to bring ethnic harmony, trust and mutual respect among all communities in order to build a united Sri Lanka.

Any development activity can not done without water, which is not only the basic needs of living beings, but is also important for food production, the sustenance of biodiversity, ecology and overall health of the environment. The pressure in the available of water resource is ever increasing due to population increase, pollution and climate change variability’s. . Therefore, provision of water supply will be the greatest challenge for development activities in the North and East.

Water resources are limited in the North, Eastern, North Central and North Western provinces of Sri Lanka. Ground water is the only source of water in much of these areas and has also been over exploited. In many areas in the North, North Central and Eastern province experiencing high amount fluoride in ground water too. Excessive use of agro chemicals and lack of sanitary toilets led to further deterioration of ground water and high levels of nitrate and Faecal Coliform are the evidence of poor quality ground water. In recent years high incidence of Chronic Kidney Disease has been reported from the North Central and Eastern provinces. In Anuradhapura alone over 200 deaths are reported annually. Although the root cause is yet unknown, there is many evidence that it is water related. Medical finding on Chronic Kidney Disease is made clear that irrespective of the root causes(s), patients continuing to consume water containing fluoride are highly detrimental. With 5-10 % of the population being affected in certain areas and mortality rates escalating, a preventive measures need to be done.

Due to the current situation in the North, IDP returnees in large numbers will resettle in the Eastern, North , North Central and Western province. This will create more pressure on water resources and aggravate the water scarcity problem as well as health problems. Water scarcity in any location leads to high incidence of water related diseases, and sanitary problems. Lack of water in a agri-based rural economy, will adversely effect the socio-economic well being of the community. Small scale home gardening is one of the prominent economic activities in North and East. Lack of water supply results in poor maintenance or total negligence of home gardens and it will have a series of net impacts on the economy. Low productivity of lands, food insecurity in rural and urban sector, nutritional deficiencies especially among children and women, lack of income, high dependency on external assistance, and poor standard of living are few out comes of a water scarce condition.

Potential of Rain Water Harvesting

In a crisis situation like this, the best option using the preserved rainwater for domestic and non domestic uses. Proper promotion of rainwater harvesting technology motivate the users to supplement their water sources and thereby reduce the over exploitation of other water resources. Rainwater harvesting is accepted as a feasible water supply option in many countries and even in Sri Lanka the potential for rainwater harvesting is well documented in the National Rain Water Harvesting Policy.

Domestic rainwater (roof water) harvesting technology introduced in other areas with similar climatic condition offer reasonably good services to the beneficiaries. Average annual rainfall experience in the target areas range from 750 mm in Mannar to 900 mm in Anuradhapura district. The rain fall pattern in Sri Lanka is bimodal and depends on two monsoon season. The driest month of the year range from June- September in Anuradhapura district and May to September in Mannar district ( 4-5 month).

An average roof area of 50 m2 in Mannar district will provide the households with at least 40 litres of water per day with an 8000 litre tank during the driest period from July- September. This will serve households with 5 people the minimum water requirement of the person which is 8 litre per day drinking and cooking. Tank of 8,000 litres will serve households with 40 litres of water per day for 6-7 months ( Figure 1).

Run off rainwater from the ground can also be collected and preserved within the home garden itself for agriculture purposes and to recharge the ground water table. For example a typical 2-acre plot of land in an area, which received annual rainfall of 1000mm, has the potential to collect and store minimum 12900 m3 of water annually through surface run off. A traditional "paththa" a garden pond of 100 m3 volume ( Figure 2) can be filled very easily within a one hour’s intense rain, and the water collected there can be used for agriculture purposes effectively by using water conservation irrigation methods such as drip irrigation, pot irrigation ect., while the excess can be guided to recharge the ground water table. A project implemented by Lanka Rain Water Harvesting Forum in Kotavehera D.S of Kurunegal District has shown that increased availability of water for drinking and crop production through introduction of rain water harvesting technologies. It has also brought many other social and economic benefits to households. It has reduce the daily average household time ( mostly women’s) spend to fetching water from 1 hr 20 min. to average 12 min. and average annual income from home gardening has increased from Rs. 4,000 to Rs. 13,000.

Rain water harvesting during Disasters

Tsunami of December 2004 had reported have contaminated 40,000 wells around the coastline of Sri Lanka, where more than 60% of the people had relied on ground water supply. Rain water harvesting systems build by Lanka Rain Water Harvesting Forum in the tsunami effected areas in the South and East of Sri Lank provides 4,000 households with drinking water supply at their door step. Easy access to water supply system has brought many other benefits to these households such as less time spend on collecting water, more reliable supply ( not waiting for bowsers), fluoride free, better sanitation practises, more water security, availability of water for home gardening ect.

Cyclone Nargis of May of 2008 which affected 37 townships in Myanmar left 130,000 people missing 2.4 million people severe effected. To prevent further disaster through lack of safe drinking water the authorities introduced improvised rain water harvesting system using temporarily shelters, bamboo gutters and easily transportable storing vessels ( Figure 3 & 4).

Rain water for Poverty Alleviation

Continuous Contour Trenching and other water harvesting technologies applied in a remote village of Hiwar Bazaar in the state of Maharashra in India which receives only 80 mm annual rainfall has transformed barren lands to fertile land and has reduced from 100% poverty in the village to 0% poverty in just 5 years period.

Similarly, in Gunzu province in North of China which receives on 380 mm of annual rainfall through a government introduced project called 1-2-1 project, which means each family in the area without availability of surface and ground water would get subsidy to build one hardened catchment yield ( roof or paved area), two under ground tanks and one piece of land for courtyard economy. The introduction of rain water harvesting has made possible the farmers to grow one harvest of rice and one harvest of irrigated corn instead of one harvest of rain fed corn before the project. The yield has been increased by three folds and the cash by four folds.

Conclusion

Simple rain water harvesting technologies introduced in IDP camps will reduce expense born by the government and other organisation on bowsering water from far distances, especially during the approaching rainy season. This will also reduce flooding to some extend. By introducing awareness on rain water harvesting technologies and water conservation practises as well as good hygiene measures to the communities from an early stage will ensure continuous practise of these technologies when they return to their own homes. Introduction of rain water harvesting technologies to resettlement areas will reduce the pressure on available resources. Practice of rain water harvesting will bring sense of responsibility to conserve water in ones own land, village and region as well as bring a new dimension of solidarity and tolerance between people and communities in watersheds, between boundaries.

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