National Conference on Water, Food Security and Climate Change in Sri Lanka Volume 1 Irrigation for Food Security PROCEEDINGS P. Weligamage, G. G. A. Godaliyadda and K. Jinapala, editors IWMI Celebrating years 1985-2010 Irrigation Department of HARTI Department Agriculture iv Proceedings of the National Conference on Water, Food Security and Climate Change in Sri Lanka, BMICH, Colombo June 9-11, 2009 Volume 1. Irrigation for Food Security P. Weligamage, G. G. A. Godaliyadda and K. Jinapala, editors INTERNATIONAL WATER MANAGEMENT INSTITUTE The editors: P. Weligamage, PhD Candidate; G. G. A. Godaliyadda, Director of Irrigation, Irrigation Department, Colombo, Sri Lanka; K. Jinapala, Researcher/Institutions Specialist, International Water Management Institute (IWMI), Colombo, Sri Lanka. Weligamage, P.; Godaliyadda, G. G. A.; Jinapala, K. (Eds.). 2010. Proceedings of the National Conference on Water, Food Security and Climate Change in Sri Lanka, BMICH, Colombo, Sri Lanka, 9-11 June 2009. Vol. 1: Irrigation for food security. Colombo, Sri Lanka: International Water Management Institute. 172p. doi:10.3910/2010.210 / food security / irrigated farming / water shortage / river basins / tanks / rice / zero tillage / water resource management / remote sensing / runoff / Sri Lanka / ISBN: 978-92-9090-726-8 Copyright © 2010, by IWMI. All rights reserved. IWMI encourages the use of its material provided that the organization is acknowledged and kept informed in all such instances. Cover photo by Mr. Sandaruwan Wickrama, Web Services Officer, International Water Management Institute. The views expressed in this publication are the views of the authors and do not neccessarily reflect the views and policies of the International Water Management Institute (IWMI), or the editors of this publication. Furthermore, IWMI makes no representation concerning, and does not guarantee the source, originality, accuracy, completeness or reliability of any statement, imformation, data, finding, interpretation or view expressed in this publication. Please direct inquires and comments to: [email protected] ii Contents Acknowledgements ................................................................................................................................. v Overview: The Volume on Irrigation for Food Security ..................................................................... vii K. Jinapala Paper 1. Water Shortage in the Lower Deduru Oya Basin ................................................................... 1 K. N. J. Kalupotha Paper 2. Utilization of Aquatic Plants: A Method to Enhance the Productivity of Water in Seasonal Tanks in the Anuradhapura District .......................................................................................... 23 J. U. Munasinghe, M. A. A. B. Dilhan and T. V. Sundarabarathy Paper 3. Instability of Paddy Production and Regional Food Insecurity in Sri Lanka ...................... 33 A. P. S. Fernando, A. M. S. Perera, K. Karunagoda Paper 4. Agriculture, Environment and Food Security in the Context of Rice .................................. 47 P. B. Dharmasena Paper 5. Impact of Water Saving Irrigation Systems on Water Use, Growth and Yield of Irrigated Lowland Rice ............................................................................................................................. 57 W. M. W. Weerakoon, T. N. N. Priyadarshani, C. H. Piyasiri and L. S. Silva Paper 6. Potential for Zero-Tillage Technique in Rice and Other Field Crop Cultivation in Rice-Based Cropping Systems in the Dry and Intermediate Zones of Sri Lanka .............................. 65 S. N. Jayawardena, S. W. Abeysekera, N. Gunathilaka and H. M. J. K. Herath Paper 7. The Importance of Seasonal Planning for Irrigation Water Productivity: Inginimitiya Experience .................................................................................................................................. 75 W. G. Gnanadasa Paper 8. The System of Rice Intensification (SRI) and Food Security Among the Poor: Opportunities and Constraints .......................................................................................................................... 81 W. G. Somaratne Paper 9. Integrating Agroforestry Characteristics into Agro-well-based Agriculture ......................... 93 Muditha Perera Paper 10. A Holistic Approach to Ensure Food Security through Cascade System Development in the Dry Zone of Sri Lanka – A Practice from Plan Sri Lanka ............................................. 101 K. H. J. K. Harischandra Paper 11. Ancient Irrigation Technology and Water Management Techniques in Sri Lanka – Appropriate Theories and Practices for Application ................................................................................... 109 Chandana Rohana Withanachchi iii Paper 12. Improved Paddy Production by Optimizing Use of Water in Major Irrigation Systems ..... 125 W. M. G. B. Giragame Paper 13. Surface Runoff Estimation Over Heterogeneous Canal Commands Applying Medium Resolution Remote Sensing Data with the SCS-CN Method ............................................... 143 Priyantha Jayakody and Nilantha Gamage List of Attendees ................................................................................................................................. 153 iv Acknowledgements The editors (hereinafter referred to as ‘we’) greatly appreciate the whole-hearted agreement between the Irrigation Department (ID), Department of Agriculture (DoA) and Hector Kobbakaduwa Agrarian Research and Training Institute (HARTI) to become partners of this conference. We would like to thank the Director General of the Irrigation Department, Mr. H.P.S. Somasiri, the Director General of the Department of Agriculture, Dr. C. Kudagamage, and the Director of HARTI, Mr. V. K. Nanayakkara for being so supportive of the event and encouraging their staff to present papers at the conference. In addition, we acknowledge the support extended by Dr. G. G. A. Godaliyadda and H.M. Jayathilaka from ID, Mr. M.M.M. Aheeyar from HARTI and Dr. Kamal Karunagoda from DoA by agreeing to become members of the conference organizing committee that was established by the International Water Management Institute (IWMI). Their valuable contributions were of much benefit in making the conference successful and productive. Mr. B. R. Ariyaratne and Ms. Janitha Godamuduna, from IWMI, also acted as members of the conference organizing committee and provided considerable support in the organization of this national conference. Funds for the conference were provided by USAID, UNDP/National Disaster Management Centre and Netafim Ltd of Israel. Their generous contributions to this event are much appreciated by us and we extend our sincere thanks to all of them. We would also like to express our thanks to all the researchers who presented papers at the conference, and for preparing reports for this volume of the conference proceedings, without whom this event would not have been possible. There were many participants from various national and international organizations whose attendance and valuable contributions to the workshop sessions made this event both productive and interesting. Professor M. S. Swaminathan from India delivered the key-note speech and the Hon. Prime Minister of the Democratic Socialist Republic of Sri Lanka, Rathnasiri Wickremanayaka attended as the chief guest. Both provided us with some very enlightening information and interesting observations, and we are extremely grateful to them for sharing their opinions with us and enriching the conference. Dr. Colin Chartres, Director General of International Water Management Institute (IWMI), Dr. Madar Samad, Regional Director (IWMI - South Asia) and Dr. Vladimir Smakhtin (Theme Leader-Water Availability and Access-IWMI) provided the encouragement and guidance to organize this nationally important conference. We must say that without their support this conference would not have been the successful event it was. Finally, our thanks go out to Ms. Pavithra Amunugama, Mr. Joseph Perera, Mr. Nimal Attanayake and Mr. Sumith Fernando for managing the editorial and production process of the proceedings. The authors would like to acknowledge the International Water Management Institute (IWMI), Irrigation Department (ID), Department of Agriculture (DoA) and the Hector Kobbekaduwa Agrarian Research and Training Institute (HARTI) for their collaboration in conducting the workshop ‘National Conference on Water, Food Security and Climate Change in Sri Lanka’. v Partners This workshop is a collaboration of the following organizations: International Water Irrigation Department (ID), Management Institute Colombo, Sri Lanka (IWMI), Colombo, Sri Lanka Irrigation Departmanet Department of Agriculture Hector Kobbekaduwa (DoA), Peradeniya, Agrarian Research and Sri Lanka Training Institute (HARTI), Colombo, Sri Lanka Donors This workshop was funded by: United States Agency for United Nations Development International Development Programme (UNDP), Colombo, (USAID), Colombo, Sri Lanka Sri Lanka Netafim Ltd., Tel Aviv, Israel Disaster Management Center, Colombo, Sri Lanka vi Overview: The Volume on Irrigation for Food Security K. Jinapala International Water Management Institute (IWMI), Colombo, Sri Lanka Background of the Conference This is the first volume on the proceedings of the national conference on ‘Water for Food and Environment’, which was held from June 9–11, 2009 at the Bandaranaike Memorial International Conference Hall (BMICH).