Criwmp cascade lecture part 2
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Awareness lecture series conducted in Anuradhapura (31.01.2019) and Trincomalee (05.02.2019) organized by Climate Resilient Integrated Water Management Project - UNDP
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Criwmp cascade lecture part 2
- 1. Strategic Agriculture against Climate Change and Natural Disasters Part 2 – Essential components of tank P.B. Dharmasena 0777 - 613234, 0717 - 613234 dharmasenapb@ymail.com , dharmasenapb@gmail.com https://independent.academia.edu/PunchiBandageDharmasena https://www.researchgate.net/profile/Punchi_Bandage_Dharmasena/contributio ns http://www.slideshare.net/DharmasenaPb Awareness lecture series conducted in Anuradhapura (31.01.2019) and Trincomalee (05.02.2019) organized by Climate Resilient Integrated Water Management Project
- 4. Why the ecosystem restoration is important? • Reduction of tank water losses causing through evaporation and bund seepage • Reduction of the risk of structural damage • Prevention of polluted water moving into the paddy field • Minimizing the tank sedimentation • Drainage improvement of the paddy field • Increasing the downstream cropping intensity through water conservation • Minimizing the impact of flood and drought • Increased availability of raw materials for cottage industries • Enhanced bio-diversity
- 5. Technical importance of the ecosystem • Upstream waterhole (godawala) – reduces the sediment inflow • Upstream tree belt (gasgommana) – acts as a wind break to reduce evaporation • Upstream meadow (perahana) – filters the suspended materials of the inflow • Upstream earth ridges (isweti) - reduces the sediment inflow • Dead storage (mada kaluwa) – maintains the downstream groundwater table • Downstream reservation (kattakaduwa) – reduces the bund seepage and prevents pollutants entering into paddy field • Downstream common drainage (kiul ela) – improves the drainage and reduces the soil salinity
- 6. Essential Components of Traditional Village Tank Systems P.B. Dharmasena Paper presented at the Seminar on Cascade Irrigation Systems for Rural Sustainability held on 9th December 2010 at SLFI, Colombo, organized by Plan Sri Lanka.
- 7. Sanitary places of women and kids Sanitary places of men Faeces as a nutrient source to paddy fields Tank-village system has been declared now as a Globally Important Agriculture Heritage System (GIAHS) by UN A Sustainable System to adapt Climate Change scenarios
- 8. Water hole Meadow Tree strip Soil ridge Tank water – no pollution, no sedimentation: safe drinking water, good storage
- 9. Shrubland Sanitory cordon Hamlet Reservation Drainage Paddy field - no salinity, good fertility: High productivity
- 21. Tank bund Upland Wetland Marshy land Water hole Tank Downstream reservation Upland Wetland Marshy land
- 22. If the bird (lapwing) lays eggs close to dead storage, maha rains will be poor If the bird lays eggs at the upstream end of the tank bed, maha rains will be high Whether forecasting
- 23. • If the weaver bird makes the nest at high level the tank water level will be high • If the weaver bird makes the nest at low level the tank water level will be low
- 24. Maha Oya in 2013
- 25. Vavuniya in 2014
- 26. • If the tamarind tree buds early, maha rains will come early • If the wood apple tree blooms more, maha rains will be high • If the Sept. rains are low, maha season rains will be high • If the Sept. rains are high, maha season rains will be poor
- 27. 600 650 700 750 800 850 900 950 1000 0 50 100 150 200 250 300 350 September rainfall (mm) Rainfall relationship between September and remaining maha season (Oct. – Feb. ) Mahailluppallama (1905 – 2003)Oct.–Feb.Rainfall(mm)
- 28. Traditional Agricultural Practices in adaptation to climate change • ‘Bethma’ practice during drought periods – It is a practice that temporarily redistributes plots of land among shareholders (paddy landowners) in part of the command area (territory) of a tank (reservoir) during drought periods • ‘Pangu’ method – Regular maintenance to avoid disasters – The tank had to be maintained properly to avoid breach, leak, and excess seepage. Repair and desiltation of tanks and cleaning of canals during dry periods are shared tasks assigned to each farmer proportionately to land ownership. • ‘Kekulama’ if the low rainfall maha is expected – Farmers advance the cultivation time using early seasonal rains whenever they feel that tanks would not get enough water to cultivate the command area. They have the experience that if September (2nd inter-monsoonal) rains are high, the total seasonal rainfall is not adequate to fill the tank. • ‘Thawalu Govithena’ during extremely dry situation – Tank bed cultivation using little rains constructing a main soil bund between deep phase and shallow phase of the tank bed
- 29. VARIATION OF RAINFALL AND IRRIGATION USE WITH CULTIVATION TIME 0 200 400 600 800 1000 1200 OCTOBER NOVEMBER DECEMBER JANUARY MONTH WATERUSE(MM) Irrigation requirement Rainfall use
- 32. Regulating Services Drought – water storage, reduced seepage and evaporation, clean water Flood – rainwater absorption, excess water drainage, flow regulatory mechanism Cyclone – Upstream tree belt, downstream reservation, sanitory cordon, forest Epidemics – malaria, water purification, waste recycling
- 33. Supporting Services Nutrients – sanitory cordon, hamlet, shrublsnd, mee tree Habitats– Downstream reservation, upstream tree belt, meadow, tank bed
- 34. Provisioning Services Cottage industry – raw materials from downstream reservation Consumables – food, fruits, vegetable from downstream reservation, tree belt and tank Materials – timber, fuel wood, farm implement, household implement Others – medicine, bio-pesticides, animal feed
- 35. Cultural Services Recreation and mental and physical health - Agricultural landscapes recreational opportunities Aesthetic appreciation and inspiration for culture, art and design Spiritual experience and sense of place - Natural heritage, spiritual sense of belonging, traditional knowledge, and associated customs. Tourism -Farm tourism allowing urbanites to reconnect with nature.