Cascade Tank Village System and identification of novel post graduate research themes
•
0 likes•14 views
Seminar on Research collaboration opportunities with School of Environment and Rural Science, University of New England, Australia - 14th September 2018, NRMC, Peradeniya, Sri Lanka
Recommended
Recommended
More Related Content
Similar to Cascade Tank Village System and identification of novel post graduate research themes
Similar to Cascade Tank Village System and identification of novel post graduate research themes (20)
More from Dr. P.B.Dharmasena
More from Dr. P.B.Dharmasena (20)
Recently uploaded
Recently uploaded (20)
Cascade Tank Village System and identification of novel post graduate research themes
- 1. Seminar on Research collaboration opportunities with School of Environment and Rural Science, University of New England, Australia - 14th September 2018, NRMC, Peradeniya, Sri Lanka Cascade Tank Village System and identification of novel post graduate research themes: 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/contributions http://www.slideshare.net/DharmasenaPb
- 2. Rajarata University of Sri Lanka • Established on 31st January, 1996. • At the inception: • Faculty of Social Sciences and Humanities, • Faculty of Management Studies, • Faculty of Agriculture and • Faculty of Applied Sciences • In 2006: • Faculty of Medicine and Allied Sciences.
- 3. Faculty of Social Sciences and Humanities Departments: • Archaeology and Heritage Management • Environmental Management • Social Sciences • Humanities • Languages • English Language Teaching
- 4. Management of Water Resources - Ancient Model, Unique to Sri Lanka River basin level Inter-River basin level Intra-River basin level Cascade level Village level Field level
- 6. Kevesastha (Northern) Upulwangiri (Kala Oya) Rakungiri (Malwathu Oya) Mahagiri (Samanala mountain area) – Kelani, Kalu, Walawe, Mahaweli Chalaka (Mi Oya) Neelagiri (Modaragam Aru) Kawasthalabha (Yan oya) Dhumaka Kaddeera (Deduru Oya) Indra (Maduru Oya, Mundeni Aru, Gal oya) Agni (Kumbukkan Oya, Menik Ganga, Kirindi Oya
- 7. Kala Oya Deduru Oya Yan Oya Malwathu Oya Kelani Ganga Gin Ganga Kalu Ganga Walawe Ganga Mahaweli Ganga River basins: 103 (16 major rivers) Major reservoirs and dams: 80 Minor tanks: 14,204 (1,262 cascades) Minor anicuts 12,942 Annual average rainfall: 2,000 mm Total land area: 65,610 km2 Total volume: 131.22 billion m³ Lost to sea: 66.18 billion m³ (>50%)
- 8. River basins – Water losses to Sea River Basin Total Basin Area (km2) River lengths (km) Total Rainfall (million m3) Drainage to Sea (million m3) % Deduru Oya 2,616 142 4,794 1,608 34.0 Kala Oya 2,772 148 4,424 587 13.0 Malwathu Oya 3,246 164 4,592 568 12.0 Yan Oya 1,520 142 2,269 300 19.0 Kelani Ganga 2,278 145 8,692 5,474 62.0 Gin Ganga 922 113 3039 1903 62.0 Kalu Ganga 2,688 129 10,122 7,862 77.0 Walawe Ganga 2,442 138 9,843 2,165 22.0 Mahaweli Ganga 10,327 335 26,804 11,016 41.0
- 9. River Basin Total Basin Area (km2) River lengths (km) Total Rainfall (million m3) Drainage to Sea (million m3) % Malwathu Oya 3,246 164 4,592 568 12.0 5 major reservoirs 1,731 rural tanks 189 tank cascade systems Source: Dept. of Agrarian Development
- 10. River Basin Total Basin Area (km2) River lengths (km) Total Rainfall (million m3) Drainage to Sea (million m3) % Kala Oya 2,772 148 4,424 587 13.0 Source: Dept. of Agrarian Development 3 major reservoirs 1,015 rural tanks 85 tank cascade systems
- 11. River Basin Total Basin Area (km2) River lengths (km) Total Rainfall (million m3) Drainage to Sea (million m3) % Kelani Ganga 2,278 145 8,692 5,474 62.0 Source: Dept. of Agrarian Development No major reservoirs 9 rural tanks No tank cascade systems
- 12. River Basin Total Basin Area (km2) River lengths (km) Total Rainfall (million m3) Drainage to Sea (million m3) % Kalu Ganga 2,688 129 10,122 7,862 77.0 Source: Dept. of Agrarian Development No major reservoirs 3 rural tanks No tank cascade systems
- 13. Inter-river basin water resources sharing model • Dambulu Oya - Malwathu Oya diversion canal (860 AD) • Malwathu Oya - Kanadara Oya diversion canal (860 AD) • Yoda Ela - Nachchduwa feeder canal (540 AD) Mahakanadarawa Nachchaduwa Kalawewa-Balaluwewa Dambulu oya Malwathu oya Kanadara oya Kala Oya Kala Oya Malwathu Oya
- 14. • Kalawewa - Thisawewa Yodha Ela (470 AD) • Nachchaduwa - Nuwarawewa feeder canal (290 AD) • Balaluwewa - Siyambalangamuwa feeder canal (290 AD) • Basawakkulama - Maha Vilachchiya feeder canal (470 AD) Kalawewa-Balaluwewa Thisawewa Siyambalangamuwa Nachchaduwa Nuwarawewa Mahavilachchiya Basawakkulama Malwathu oya Thalawa oya Kala oya Intra-river basin water resources sharing model Kala Oya Malwathu Oya
- 16. The cascade retains water within the river basin: • Irrigation, • Minimize flood damage • Mitigate drought impact • Protect ecosystems through enhanced groundwater Network of tanks and streams in the form of cascades – Anuradhapura District
- 17. Nachchaduwa Kanadarawewa Vilachchiya Kalawewa and Balaluwewa Huruluwewa Network of tanks and streams in the form of cascades – Anuradhapura District Anuradhapura District: • 6 major reservoirs • 457 tank cascades • 3,000 rural tanks Malwathu Oya river Kala Oya river Yan Oya river
- 18. Tank clusters or cascades Source: Kadupitiya, 2018
- 19. Tank clusters or cascades Source: Kadupitiya, 2018
- 20. Distribution of tank cascades in Sri Lanka Source: Dept. of Agrarian Development Main factors: 1. Morphology (landscape) • Lower elevation, • Moderate undulation 2. Rainfall • Bimodality • 800 - 2000 mm/ year 3. Soil and geology • Wanni and Vijayan complexes • Regolith aquifers • Low infiltration • RBE – LHG and some on RYP and IBL
- 21. Landscape of aTank –Village System Village level model
- 22. Godawala Perahana Gasgommana Iswetiya Tank water – no pollution, no sedimentation: safe drinking water, good storage
- 23. Landa Thisbambe Gangoda Kattakaduwa Kiul-ela Paddy field - no salinity, good fertility: High productivity
- 24. Field level water management model • Integrated water management approach • Groundwater on poorly drained soil phase • Maximum use of seasonal rainfall • Irrigation water: • Minimum use in major (maha) season saving tank water for minor (yala) season Spill water Shallow water Deep water Dead storage
- 25. Field level water management model • Water issue through keta horowwa or bisokotuwa
- 26. Field level water management model • Water distribution through karahana
- 27. Water management under stressed conditions • Very limited water in the tank: ‘Bethma’ practice • 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) • Expecting the risk of flood: ‘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. • If rainfall is expected low during major season:‘Kekulama’ • 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. • No water in the tank – extremely dry: ‘Thawulu Govithena’ • Tank bed cultivation using little rains constructing a main soil bund between deep phase and shallow phase of the tank bed