Water resources strategies to increase Food Production in the semi-arid troPics With Particular emPhasis on the Potential oF alluvial groundWater david love WATER RESOURCES STRATEGIES TO INCREASE FOOD PRODUCTION IN THE SEMI-ARID TROPICS WITH PARTICULAR EMPHASIS ON THE POTENTIAL OF ALLUVIAL GROUNDWATER WATER RESOURCES STRATEGIES TO INCREASE FOOD PRODUCTION IN THE SEMI-ARID TROPICS WITH PARTICULAR EMPHASIS ON THE POTENTIAL OF ALLUVIAL GROUNDWATER DISSERTATION Submitted in fulfillment of the requirements of the Board for Doctorates of Delft University of Technology and of the Academic Board of the UNESCO-IHE Institute for Water Education for the Degree of DOCTOR to be defended in public on Thursday, 12 September 2013, at 12.30 hrs in Delft, the Netherlands by David LOVE Bachelor of Science, University of Zimbabwe Bachelor of Science Honours and Masters of Science, University of Stellenbosch, South Africa born in Lusaka, Zambia. This dissertation has been approved by the supervisors: Prof. dr. S. Uhlenbrook Prof. dr. ir. P. van der Zaag Composition of Doctoral Committee: Chairman Rector Magnificus TU Delft Vice-Chairman Rector UNESCO-IHE Prof. dr. S. Uhlenbrook UNESCO-IHE / Delft University of Technology Prof. dr. ir. P. van der Zaag UNESCO-IHE / Delft University of Technology Prof. dr. ir. H.H.G Savenije Delft University of Technology Prof.dr.ir. N.C van de Giesen Delft University of Technology Prof dr. C. de Fraiture UNESCO-IHE / Wageningen University Prof. dr. D. Mazvimavi University of the Western Cape, South Africa Dr. ir.T.N. Olsthoorn Delft University of Technology, reserve member CRC Press/Balkema is an imprint of the Taylor & Francis Group, an informa business © 2013, David Love All rights reserved. No part of this publication or the information contained herein may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, by photocopying, recording or otherwise, without written prior permission from the publishers. Although all care is taken to ensure the integrity and quality of this publication and the information herein, no responsibility is assumed by the publishers nor the author for any damage to the property or persons as a result of operation or use of this publication and/or the information contained herein. Published by: CRC Press/Balkema PO Box 11320, 2301 EH Leiden, The Netherlands e-mail: [email protected] www.crcpress.com - www.taylorandfrancis.com ISBN 978-1-138-00142-8 i Acknowledgements In late 2003, I was working as a lecturer in the Geology Department at the University of Zimbabwe, when WaterNet (of which the Department is a member) invited us to participate in preparing a proposal to the Challenge Program on Water and Food for a transdisciplinary water research project in the Limpopo Basin. The proposal was successful, and I was subsequently recruited as a PhD fellow and as a part-time project coordinator at WaterNet. WaterNet is without doubt one of the most dynamic organisations that I have worked for. It is also modern, delivering education, research and outreach through teams from many different institutions (Mode 2 Knowledge Production per Gibbons) that make up the network. This is especially important for our sub-region, as many countries in SADC have small populations and thus do not always have world class human resources in some areas of expertise – but it can always be found by sharing with neighbours. Our PN17 project Integrated Water Resources Management for Improved Rural Livelihoods, set out to demonstrate that improving water management at any scale improves people’s livelihoods. I hope that my work has in its own way contributed to this and provides the Mzingwane Catchment Council with some useful insights and tools for the management of their sub-basin. I was lucky to participate in such an interesting project and work with such great colleagues. The science has been fascinating, dealing with hydrogeology, hydrology, crop science and development – and interacting with and learning from colleagues in all these fields. I was priviledged to receive awards for two of my papers: the Tison Award from the International Association of Hydrological Sciences and the Phaup Award from the Geological Society of Zimbabwe. This has been a personal journey for me, not just the science and the wonderful communities we worked with. The initiation of the project coincided with my marriage to Faith, and discovering that her eldest brother, Phanuel Ncube, chaired the Mzingwane Catchment Council - the water management authority that WaterNet planned to work with. So this journey has been a fundamental part of my family life as well as my professional life. To my promoters and supervisors, my sincere appreciation for your guidance, mentorship, support and endless patience. Stefan Uhlenbrook and Pieter van der Zaag provided the overall scientific guidance and the confidence and support to keep going through the long years of this research, especially when my morale was low. At no time were you too busy to help, correct and guide. Richard Owen provided the detailed guidance on hydrogeology and encouraged the growth of my love for the alluvial aquifers of the hotter and drier parts of our sub-continent – as well as giving me support in matters personal and spiritual. Steve Twomlow guided me through the science of semi-arid lands, field discipline and support at ICRISAT Matopos Research Station. This work is part of a trans-disciplinary trans-institutional project, and I wish to thank my many colleagues in the Limpopo Basin, including my PhD co-fellows, sekuru Walter Mupangwa, Collin Mabiza, Paiva Munguambe and Manuel ii Magombeyi. At the Zimbabwe National Water Authority: Tommy Rosen, Elisha Madamombe, Charles Sakuhuni, and my brother-in-law and longstanding chairman of the Mzingwane Catchment Council, tezvara Phanuel Ncube. At ICRISAT, Andre van Rooyen, John Dimes and my mai gurus Bongani Ncube and Sifiso Ncube, and the drivers with whom I spent so much time in the field, especially Mr Masuku, Mr Manyani, Mr Mlotshwa and Mr Mpofu. At the University of Zimbabwe, Hodson Makurira, Innocent Nhapi and Aiden Senzanje, and the technicians who also spent time with me in the field, especially Farai Zihanzu, Percy Sena and Douglas Maguze. At WaterNet, Lewis Jonker, Johan Rockström, Themba Gumbo, Bongani Ncube (again), mkoma Washy Nyabeze, Nick Tandi, Martha Hondo, Moriah Makopa, Admire Mutowembwa, Jean-Marie Kieshye-Onema and Rennie Munyayi. At the Dabane Trust, Steve Hussey and Ekron Nyoni. In the Netherlands, I benefitted greatly from interactions with many staff and PhD fellows, especially Gerald Corzo Perez, with the time developing HBVx together and with whom I shared the Tison Award - and also Marloes Mul, Hodson Makurira (again), Collin Mabiza (again), Marieke de Groen, Ilyas Masih, Jeltsje Kemerink and Ann van Griensven. In South Africa, to my new colleagues at Golder: Keretia Lupankwa, Koovila Naicker, Nico Bezuidenhout and Gerhard van der Linde, for your support in the last months of this long journey, and Washy Nyabeze (again), Marieke de Groen (again), Themba Gumbo (again) and Bongani Ncube (again) for your advice and encouragement. To the many Masters students from University of Zimbabwe, UNESCO-IHE, TU Delft and University of Twente, it was a pleasure supervising you and your contributions to this work, direct and indirect is highly valued. To my field assistants, Tius Sibanda, Sanelisiwe Sibanda, Tutanang Nyati, Patrick Nyati, Regis Mukwane, Brighton Sibanda, Daniel and Saddam Mkwananzi and my mai ninis Sipatisiwe and Sipetokuhle Ncube your contribution was also vital. Additional rainfall data was obtained with the help of the Beitbridge Bulawayo Railway Company, Mazunga Safaris, Tod’s Guest House and the communities of Zhulube (Insiza), Fumukwe and Manama (Gwanda), Maranda, Nemangwe and Chengwe (Mwenezi) and Dendele, Tongwe, Malala and Masera (Beitbridge). The assistance of baba mkuru Hayi Mpofu (Zhulube Irrigation Scheme), Felix Whinya (Zhovhe Dam), Tod’s Guest House, Paul Bristow and Rob Smith (Mazunga), and the District Administrators and Rural District Councils of Insiza, Gwanda, Mwenezi and Beitbridge Districts has been essential and is gratefully acknowledged. This thesis is an output of the CGIAR Challenge Program on Water and Food Project 17 ‘‘Integrated Water Resource Management for Improved Rural Livelihoods: Managing risk, mitigating drought and improving water productivity in the water scarce Limpopo Basin’’, led by WaterNet, with additional funding provided by the International Foundation for Science (Grant W4029-1). Work in the field was also supported by ICRISAT Matopos, the Dabane Trust, the University of Zimbabwe Department of Geology and World Vision Insiza ADP. Piezometers were designed and manufactured by the Dabane Trust and installed with their assistance. The opinions and results presented are those of the author and do not necessarily represent the donors or participating institutions. iii Reference discharge data were provided by the Zimbabwe National Water Authority and rainfall data by the Department of Meteorological Services, Zimbabwe Ministry of Environment and Tourism. Additional data were also availed by the Zhovhe Water Users Association. Jan Seibert kindly provided the HBV light 2 code. To my dear wife Faith, for your endless patience, love and support, and to our two children born during this work, Kathleen Taboka and James Robert Langanani, a big thank you for bearing with me when I was away, accompanying me some of the time and supporting me all the way through. Finally, I give honor and glory to God, for all His gifts to me, and especially for the gifts of intellect and science, that we may know more of the workings of this World. David Love, Midrand, August 2013 iv v Summary A number of hydroclimatic and institutional factors converge to emphasise the need for investment in water management and water resources modelling in southern Africa. Water demand continues to rise, as urban areas expand and as agricultural water demand rises to meet the millennium development food security goals.