RAINWATER HARVESTING FOR HOME GARDENS IN DRY ZONE OF                        SRI LANKA                                     ...
Agriculture is the main source of income of nearly 80% of the people living in these areas.Poverty is widespread mainly in...
Table 01: The summarised results of the survey conducted in the Kurundamkulama, unit 11village.                      Month...
Low Cost Rain Water TanksSurface runoff tanks were built at the bottom of the land towards the slope, where the runoffrain...
Water Collected and Extracted In TanksTable 2. Collection and usage of water in surface runoff tanks in both seasons  Name...
Table 3. Crops Cultivated, land area, crop produce and income earned during Maha season in2003              2002          ...
Farmer 4                      <1/4       Loofer,Thibbatu, Papaya         9000/-*      100/-                               ...
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Sri Lanka; Rainwater Harvesting for Home Gardens in Dry Zone of Sri Lanka

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Sri Lanka; Rainwater Harvesting for Home Gardens in Dry Zone of Sri Lanka

  1. 1. RAINWATER HARVESTING FOR HOME GARDENS IN DRY ZONE OF SRI LANKA P. A. Weerasinghe Faculty of Agriculture, Rajarata University of Sri Lanka Puliyankulama, Anuradhapura, Sri Lanka. aruni50@yahoo.com T. N. Ariyananda Lanka Rain Water Harvesting Forum 28/3A, Subhadrarama Mawatha Nugegoda, Sri Lanka tanuja@sltnet.lk C.S. Weeraratna Sugarcane Research Institute Telawala Road Ratmalana, Sri Lanka csweera@sltnet.lk ABSTRACTA study was conducted on how harvested rainwater in low cost surface runoff tanks wouldimprove the income level of households living in the dry zone area of Sri Lanka. To collect rainwater, low cost ferro cement surface runoff tanks with 5 m3 capacity were built at the bottomof the land towards the slope, where the runoff rainwater flows through the contours into thetank. Three cropping patterns were introduced, ie. one crop planted between contour bounds,mixed crops planted on the same contour and N- Fixing trees (i.e. Gliricidia) planted on thecontour. The contouring the land helped to direct water to the tank as well as to controlerosion. Results showed that the three different cropping patterns used had no significantdifference in amount of water collected in tank or to the income increase by cultivation.However, regardless of the cropping patterns 100% of income increase was observed in Mahain compare with the income prior to the project intervention. Due to availability of water,farmers started cultivate in Yala 2004 which they have not done in past. Farmers used excesstank water not only for cultivation but also to generate income by other means eg. brickmaking. INTRODUCTIONOut of 6 million hectares of Sri Lanka, around 4 million are in the Dry Zone which has fiveAgro- Ecological Regions (AERs). The rainfall in the Dry Zone varies from 750 mm to 1500mm. Around 1000 mm is received during the Maha season (October – February) and 500 mmin the Yala season (April – July).Paddy is mainly cultivated in the Dry Zone. Among field crops such as chilly, maize, pulses,some vegetables and fruits crops are taking prominent place in dry zone cultivation.. Anaverage lowland holding is 0.4 hectares and an upland holding is 1.2 hectares. Theagricultural productivity in the Dry Zone has stagnated during the last few decades mainly dueto a host of factors and one is inadequate water. 1
  2. 2. Agriculture is the main source of income of nearly 80% of the people living in these areas.Poverty is widespread mainly in the Dry Zone of Sri Lanka. For example in Anuradhpuradistrict in dry zone, around 50% of the households are below poverty level (Annual Report,Samurdhi Authority 2002) ie. below a monthly income of Rs.1500/- which is equivalent to US$15 Hence successful crop production determines to a great extent their poverty level anddepends on the efficient use of available water and some other factors. The rainfall is lessduring Yala season and available water for cultivation of crops during this period isinadequate.From the total rainfall around 25% of rain water is lost in the form of surface run-off andconserving this water will not only promote crop growth in areas where water is limiting, butwill also reduce soil erosion. Among various methods of storing of water harvesting andconservation, the most common and economical method is storing of water in sub-surfacetanks (Gould J and Nissen P. E, 1999). Therefore, a study was conducted on how harvestedrainwater in low cost surface runoff tanks would improve the income level of households livingin the dry zone area of Sri Lanka. METHODOLOGY OF THE STUDYThe Site SelectionThe selected site, Kurundamkulama, Unit 11 is located within the Mihintale DivisionalSecretariat in Anuradhapura district in Sri Lanka. The area gets an annual average rainfall of1000 mm in two seasons, from October to December, during the Maha season (around 700mm) and from May to July, during the Yala season (around 300 mm). The main source ofwater for the village is one tube well and one agro well.Selection of BeneficiariesFrom the socio economic survey conducted within households in the village, nine (9)households were selected for the research after circulating a questionnaires and following abrief discussion to confirm the facts stated in questionnaires (Table1). Questionnaires were mainly focused on, Ø Details of Family members Ø Educational level Ø Income Sources Ø Description of land Ø Last year income gained in Maha and Yala seasonsThe selection criteria for Farmers were based on scarcity of water for cultivation, monthlyincome level (below Rs.1,500/- which is US $ 15. cultivable land minimum of one acre (withone exception), sloping land and willingness to participate.Information Generated From the QuestionnaireThe information generated from the questionnaire is summarised in the table 1.The mainoccupation of the household is farming. The education level is generally up to G.C.E. OrdinaryLevel. The average income earned during 2002 Maha crop production was Rs. 775/- perfarmer. Only one farmer earned an income of Rs. 1,250/- during 2002 Yala and rest of thehouseholds did not cultivate during Yala season due to non availability of water. Ninetypercent of the households surveyed are below the poverty line (monthly income is below Rs.1,500/-). The average number in household is four (4) members. 2
  3. 3. Table 01: The summarised results of the survey conducted in the Kurundamkulama, unit 11village. Monthly No. of Acers No. of Condi 2002 2002 Income No. of Cultivated memb tion of Product Income (Rs) Farmer (Rs) Acers 2002 ers Land Maha Yala Maha Yala Maha YalaFarmer 1 3 1000/- 1 Slope ½ ¼ Chilli 1350/- Long beanFarmer 2 Chilli Brinjal 2 1000/- 3 1/2 Slope 1 1675/- Long bean NOT CULTIVATED NOT CULTIVATEDFarmer 3 4 1000/- 1 Slope ¾ NOT CULTIVATEDFarmer 4 Chilli 5 1500/- 1½ Slope 1 1000/ BrinjalFarmer 5 1000/- Chilli 4 1 Slope ¾ 750/- MaizeFarmer 6 4 1500/- 1 Slope ¾ Chilli 600/-Farmer 7 4 1000/- 1 Slope ½ MaizeFarmer 8 4 1000/- ½ Slope ½ Chilli 1000/Farmer 9 Chilli Long 6 2000/- 1½ Slope 1 ½ 600/- 1250/ bean BrinjalLand PreparationFirst, the farmers were requested to draw a sketch map showing the direction where the landis sloping, in order to select the site to build the runoff tank. They were also asked to marksuitable place for growing crops, location of the house and the place where the annual andperennial plants were already grown in the land.Three methods of planting crops were introduced, Ø One crop planted between contour bounds Ø Mixed crops planted on the same contour Ø N- Fixing trees (i.e. Gliricidia) planted on the contourTogether with farmers contour mapping of the land was done and advice was given, toprepare the land accordingly. The nine farmers were grouped in to three and each group wasassigned a cropping method. Objective of this grouping was to measure the effectiveness ofeach cropping methods separately.Crops Recommended For Maha and YalaIn consultation with the farmers the project team recommended the cultivation of Long bean(Vigna spp) Chillies (Capsicum spp) , Maize (Zea mays) and Brinjals (Solanum spp.) duringYala. The farmers were provided with seeds and water required for the crops during the latterpart of the rainy season was taken from the run-off tank constructed in the bottom of the slopeIn 2004 Yala season, farmers recommended to cultivated crops such as Snake gourd (Luffa)Thibbatu (Solanum spp.) and Papaya (Carica papaya)Rain Fall MeasurementsThrough out the research period rain fall was monitored using a rain gauge at one of thehouseholds. 3
  4. 4. Low Cost Rain Water TanksSurface runoff tanks were built at the bottom of the land towards the slope, where the runoffrainwater flows across through the contours into the tank. Rainwater before it reaches the tankflows through small field of grass grown near the mouth of the tank and then through a meshand finally through sedimentation traps. The traps are made in such a way, that the first step isthe widest and second and final steps being proportionately narrowest so, that the waterdoesn’t rush into the well but flows slowly filtering the sediments. 3Constructed Ferro cement tanks were 5000 L (5 m ) in capacity and 190 cm deep with 210 cmdiameter (Diagram 01). Ferro cement was selected over brick tank as the cost of Ferrocement tank is two third cheaper. The average cost of constructing a Ferro-cement tank wasRs 7,500/- (US$ 75) at the time of construction i e. in year 2003 (excluding unskilled labour).The beneficiary contributed in the construction by providing unskilled labour and localconstruction material. Chicken wire mesh was used to reinforce the tank since it is cheaperand available freely at the local market. Hand pump with a water meter was fixed to the tank tomeasure the amount of water drawn. The tank was covered with either tar sheet cover orpolyethylene cover to prevent evaporation and developing algae through exposure to sun. Toprevent the breeding of mosquitoes in these tanks farmers were advised to grow fish aspredators.The construction of the tanks was finished in June 2003 and collection of surface runoff waterstarted since then.Two selected masons from the village were initially trained in construction of rainwater tanks.These masons were used to build the tanks in the village. 210 cm 200 cmTar sheet or Diagram 1. Schematicthatched cover 85 cm 3 structure of a 5m under ground Ferro cement surfaceHand pump 190 cm RESULTS AND DISCUSSIONRainfall PatternThe total rain fall received from June 2003 to July 2004 at Kurundankulama was 998mm. Therain fall received during Maha (October - February) 2003/04 was 537mm, Yala (April - July)2004 was 408 mm, intermittent (March) rain was 56.7 mm.During the year 2003/04, the area received a Maha rain fall of 750 mm which was 28 percentless than usual average rain fall. During Yala 2004 too, less rainfall was received than normal.In fact whole of the district and the province faced a severe drought during this year. 4
  5. 5. Water Collected and Extracted In TanksTable 2. Collection and usage of water in surface runoff tanks in both seasons Names Maha 2003 Yala 2004 Volume of water Volume of water Volume of water Volume of water 3 3 3 3 collected in (m ) extracted (m ) collected in (m ) extracted (m )Farmer 1 7.7 0.4556 2.1 2.0411Farmer 2 7.12 0.049 8.6 3.2116Farmer 3 4.71 2.46 4.5 1.8744Farmer 4 2.83 0.0847 7.6 1.4768Farmer 5 6.6 1.43 8.2 1.3105Farmer 6 1.63 0.0501 5.8 2.5077Farmer 7 5.46 1.32 2.5 2.9839Farmer 8 5.99 0.2962 2.8 1.7507Farmer 9 6.72 1.8747 3.4 3.0916Total 48.76 8.0203 45.5 20.2483Average 5.417 0.8911 5.055 2.2498As shown in the Table 2., in early Maha season less water was extracted from the run offtanks. This was due to the fact that the beginning of cultivation was done with rain water.However, the tank water was used for cultivation during the latter part of the season when therain ceased. The availability of the water in the tank helped farmers to save not only theirannuals but also the perennial crops in their home gardens.During Yala season due to the drought, farmers were depend on the harvested rainwater fortheir cultivation. Extracted water for cultivation was more than double compired to Mahaseason. CROP AND INCOMEMaha seasonWhen the total income of beneficiaries for the Maha season 2003 was compared with that of2002, a marked increase in their income was observed. Prior to the project intervention theaverage gross income of the beneficiary households was Rs.996/- where as in 2003 after theproject intervention the Maha income rose up to an average of Rs.2084/- thus doubling theirprevious income (Table 3).Yala SeasonDuring 2003 Yala season before the project intervention, except farmer no. 9, none of thefarmers had cultivated any crops due to insufficient water. The profit of farmer 9 wasRs.1250/- for 2003 Yala season.In 2004 Yala season, after discussion with the farmers in the project group, seven of thebeneficiary group cultivated crop such as snake gourd, Lufa, Thibbatu (Solanum sp.) andPapaya. Two of the farmers were sick during the Yala season and started cultivation later.Farmer no. 1 and 4 used their collected rain water for brick making. Their income during thisperiod was Rs.7000/- and 9000/- respectively. Average Gross income of the seven farmerswho cultivated and sold their products by the end of the Yala season was Rs.622/- (Table 04).Although the average income earned during the Yala season was less than the Maha season2003, it was a considerable achievement that farmers started cultivate in Yala season too. 5
  6. 6. Table 3. Crops Cultivated, land area, crop produce and income earned during Maha season in2003 2002 Maha 2003 Maha Season Season Farmer Income No. of Total Cultivated Crop (Rs)/ Acres Income Expenses and produce Season Cultivated (Rs)/Season (Rs)Farmer 1 Long bean 29Kg 4275/- 1355/- 1350/- 1 Brinjals 260Kg,Chilli 1Kg Maize 300KgFarmer 2 1/2 Long bean 35Kg, 1335/- 170/- 1675/- Chilli 37Kg,Maize 150Farmer 3 1/2 Long bean 30Kg, 5033.50 1207/- - Chilli 179Kg, Brinjals 46Kg, Maize 250Farmer 4 1000/- 1/2 Long bean 13.5 Kg 3751.50 735/- Chilli 52Kg, Brinjals 400KgFarmer 5 1 Long bean 53Kg 1595/- 712/- 750/- Chilli 20Kg, Maize 100 KgFarmer 6 1/4 Long bean 10Kg 180/- 483/- 600/- Chilli 3KgFarmer 7 1/4 Long bean 5.5 Kg 150/- 205/- - Chilli 12.5 KgFarmer 8 1/4 Long bean 26Kg 1745/- 865/- 1000/- Brinjals 30Kg, Chilli 23KgFarmer 9 1/2 Chilli 18Kg Brinjals .691/- 513.50 600/- 11Kg Long bean 27KgAverage 996.40 1/2 2084 694Table 4. Crops Cultivated, land area, the produce and income earned during Yala season in2003Farmer 2002 Yala Season 2003 Yala Season Cultivated Crop & Total No. of Income Income Quantity Expenses Acres (Rs) (Rs) CultivatedFarmer 1 Lufa 20Kg, Thibbatu - * - 40Kg, Papaya 7000/- *Rain water in tank used for brick makingFarmer 2 1/4 Snake gourd 19Kg, Long 1225/- - bean 9Kg, Pumpkin 51Kg, Brinjal 12KgFarmer 3 <1/4 Loofer 8Kg, Snake gourd 235/- - 5Kg, Thibbatu, Papaya, Pumpkin 6
  7. 7. Farmer 4 <1/4 Loofer,Thibbatu, Papaya 9000/-* 100/- Rain water in tank used for brick makingFarmer 5 1/4 Loofer 23Kg, Capsicum 1290/- 100/- 3Kg, Thibbatu, PapayaFarmer 6 1/4 Loofer 12Kg , Thibbatu 260/- 78/-Farmer 7 1/4 Loofer, Thibbatu, Papaya 118/- -Farmer 8 1/4 Loofer, Thibbatu, Papaya, 185/- 130/- leafy vegetablesFarmer 9 Rs1250/ 1/4 Loofer 8Kg, Pumpkin, 440/- 40/- PapayaAverage 1/4 Rs. 622* Rs. 56* excluding income gained from brick making OUTPUT OF THE PROJECTThe contouring the land helped to direct water to the tank as well as to control erosion.Planting of Gliricidia on the contour bunds provided mulch and N-fixing bacteria to the soil.However, the benefit of gliricidia was not observed during the research period as the effectsare realized over a long period.There was no significant difference of crop yields among the 3 cropping patterns used.Longer term data is needed to observe any significant difference if there is any.Two hundred percent of income increase was observed in Maha 2004 in compare with theincome prior to the project intervention.Farmers started cultivated in Yala season too, due to the availability of water.The water saved during Maha was a great asset to the farmers, as even during the Mahaseason when the rain ceased earlier, the only way they were able to save their crop was byusing the water in the rainwater tanks.Two trained masons are now been used by other projects to built Ferro cement tanks.Discussion with farmers at the end of the project has indicated that bigger capacity tank such 3as 10m would have been more useful, especially since this Maha season rains ceased early. REFERENCESAnnual Report, 2002. Samurdhi Authority, Ministry of Samurdhi, Sri Lanka.Gould J and Nissen Petersen E, (1999).Rain Water Catchments Systems for Domestic SupplyIntermediate technology Publication Ltd. UK 7

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