National Conference on Water, Food Security and Climate Change in Sri Lanka Volume 2 Water Quality, Environment and Climate Change PROCEEDINGS
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National Conference on Water, Food Security and Climate Change in Sri Lanka Volume 2 Water Quality, Environment and Climate Change PROCEEDINGS Alexandra Evans and K. Jinapala, editors IWMI Celebrating years 1985-2010 Irrigation Department of HARTI Department Agriculture Proceedings of the National Conference on Water, Food Security and Climate Change in Sri Lanka, BMICH, Colombo June 9-11, 2009 Volume 2. Water Quality, Environment and Climate Change Alexandra Evans and K. Jinapala, editors INTERNATIONAL WATER MANAGEMENT INSTITUTE The editors: Alexandra Evans, Researcher/Wastewater and Livelihoods, International Water Management Institute (IWMI); K. Jinapala, Researcher/Institutions Specialist, International Water Management Institute (IWMI). Evans, 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. 2: Water quality, environment and climate change. Colombo, Sri Lanka: International Water Management Institute. 186p. doi:10.3910/2010.205 / water quality / river basins / wetlands / water resource management / climate change / rain-fed farming / environmental flows / soil management / case studies / irrigation schemes / models / groundwater / aquifers / wastewater irrigation / Sri Lanka / ISBN: 978-92-9090-722-0 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 necessarily 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, information, data, finding, interpretation or view expressed in this publication. Please direct inquires and comments to: [email protected] ii Contents Acknowledgements ................................................................................................................................. v An Overview: Water Quality, Environment and Climate Change Alexandra Evans ........................................................................................................................vii Paper 1. How to Minimize the Negative Impacts on Bundala National Park due to Irrigation Development of the Kirindi Oya River Basin ............................................................................. 1 W. D. S. Abeywickrama Paper 2. Wetlands and Agriculture – A Case for Integrated Water Resource Management in Sri Lanka .................................................................................................................................... 7 Sithara S. Atapattu, Sanjiv De Silva and Sonali Senaratna Sellamuttu Paper 3. Environmental Flow Assessment: Recent Examples from Sri Lanka .................................... 23 P. Dissanayake, N. Weragala and V. Smakhtin Paper 4. Non-user Benefits Emanating from Enhanced Water Flow to the Yala Protected Area Complex ............................................................................................................................. 37 Parakrama Weligamage, Walter R. Butcher, Keith A. Blatner, C. Richard Shumway and Mark Giordano Paper 5. The Impact of Inappropriate Soil Management on River Water Quality: A Case Study in the Kurundu Oya Sub-catchment of the Upper Mahaweli Catchment, Sri Lanka ......................... 49 M. G. T. S. Amarasekara, R. M. K. Kumarihamy, N. D. K. Dayawansa and R. P. De Silva Paper 6. Availability and Spatial Variability of Plant Nutrients in Paddy Fields of Wilgoda Irrigation Scheme in Kurunegala................................................................................................................ 61 D. N. Sirisena, W. M. U. K. Rathnayake and W. M. J. Bandara Paper 7. Assessment of Risks to Water Bodies due to Residues of Agricultural Fungicide in Intensive Farming Areas in the Up-country of Sri Lanka using an Indicator Model ...............69 Ransilu C. Watawala, Janitha A. Liyanage and Ananda Mallawatantri Paper 8. Preliminary Groundwater Assessment and Water Quality Study in the Shallow Aquifer System in the Attanagalu Oya Basin ......................................................................................... 77 R. S. Wijesekara and C. Kudahetty Paper 9. Household Water Security through Stored Rainwater and Consumer Acceptability: A Case Study of the Anuradhapura District ........................................................................................... 87 M. A. C. S. Bandara, Ranjith Premalal De Silva and N. D. K. Dayawansa Paper 10. Observed and Projected Climatic Changes, Their Impacts and Adaptation Options for Sri Lanka: A Review .................................................................................................................. 99 Nishadi Eriyagama and Vladimir Smakhtin iii Paper 11. Identifying the Impact of Tidal Level Variation on River Basin Flooding .........................119 M. D. E. K. Gunathilaka, W. A. L. Wikramanayake and D. N. D. Perera Paper 12. Rainfall Fluctuation and Changing Patterns of Agriculture Practices ................................ 127 Sulakshika Senalankadhikara and L.Manawadu Paper 13. Climate Change and Rain-fed Agriculture in the Dry Zone of Sri Lanka ......................... 141 C. R. Panabokke and B. V. R. Punyawardena Paper 14. Climate Change, Local Institutions and Adaptation Experience: The Village Tank Farming Community in the Dry Zone of Sri Lanka ..............................................................................147 Athula Senaratne and Kanchana Wickramasinghe Paper 15. Potential to Increase the Area under Paddy Cultivation with Domestic and Municipal Wastewater Irrigation in Kurunegala District ..........................................................................157 U. S. C. Udagedara and M. M. M. Najim List of Attendees .................................................................................................................................. 167 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