Potential Water Conflicts in Mali
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Potential Water Conflicts in Mali Identification of competing claims for surface water and the impact of climate change in the West Niger Basin June 2008 Geert Jonathan van Dijk Department of Water Resources Management Faculty of Civil Engineering and Geo Sciences Delft University of Technology in cooperation with Royal Haskoning Cover photo © Arthur Morris/Corbis Acknowledgements This study has been carried out with the Delft University of Technology and Royal Haskoning. To both organisations I owe my gratitude for the support I received. In particular, I want to thank my primer supervisors dr. ir. Trilokya Pradhan (Royal Haskoning) and dr. ir. Maurits Ertsen (Delft University of Technology) for all their comments and suggestions. Additionally I want to thank prof. dr. ir. Nick van de Giesen and dr. ir. Robbert Verhaeghe for taking place in my graduation committee. Special thanks to my colleagues at Royal Haskoning, the Direction Nationale de l´Hydraulique, Mali and my colleague graduates at the Delft University of Technology for sharing their expertise and having a good time. Also, I am grateful for the patience of the many Malians willing to share their knowledge with me in French. Moreover, this research would not have been possible without the support of Deltares, formerly WL Delft Hydraulics. They supplied a license for RIBASIM and a simulation of the West Niger Basin. Consequently, the consent of Deltares is needed for the distribution of the simulation and the results of the RIBASIM model. Furthermore, I want to thank Het Lamminga Fonds for funding my ticket for the research part of this study in Mali. Additionally, I want to thank my friends and family, especially my parents, for their support during my study. Finally, I want to thank the Lord for His creation of all the beauty and complexity of Niger River basin, and for the privilege I have to study it. June 2008 I G.J. van Dijk Acronyms ABN Authorité du Bassin de Niger/Niger Basin Authority CSI Controlled Submersion Irrigation DNA Direction Nationale de l’Agriculture DNCN Direction Nationale de la Conservation de la Nature DNGR Direction Nationale Génie Rurale DNH Direction Nationale de l´Hydraulique DNSV Direction Nationale Service Vétérinaire EDMsa Energie du Mali S.A. FAO Food and Agriculture Organisation ID Inner Delta IER Institute Economique Rurale MSL Mean Sea Level ODRS Office du Développement Rural Selingué OMVS Organisation pour la Mise en Valuer du Fleuve Sénégal Organsation ON Office du Niger OPIB Office du Perimètre Irrigué Baguineda ORM Office du Riz Mopti ORS Office du Riz Segou SIGMA Système Informatique de Gestion des resources en eau du Mali June 2008 II G.J. van Dijk Summary The West Niger Basin is the topic of many recent studies. The development of a hydropower dam and the extension as well as modernisation of the irrigated agriculture, in a sensitive ecologic system, combined with climatic changes, creates a lot of research potential. This study focuses on the identification of competing claims for surface water resources and the influence of climatic change in the West Niger Basin. Within this framework the comprehension of the hydrology of the basin is important. The Niger rises from the mountains in Guinea, where the climate is tropic and the rains are abundant during the rainy season. Along the river the precipitation volume and the length of the rainy season gradually decreases, resulting in a semi-arid, Sahelian climate at the end of the West Niger Basin. Consequently, the Niger River discharge is dominated by the water supply from the tropical zone, causing a flood wave during the rainy season There are several fields of interest that depend on the water and sometimes even on the hydrologic regime of the Niger River. In this study hydropower, irrigation and the Inner Delta are evaluated. Hydropower stations demand enough water to optimally use their reservoirs for high continuous power generation. This is a relatively inexpensive and therefore lucrative way to produce energy. Fully managed irrigation schemes demand water during the dry and rainy season. They are quite insensitive to changes in the water supply system. Consequently, they have good yields and host many farmers. In contrast, controlled submersion irrigation fully depends on a large yearly flood wave for sufficient water supply. This makes this type of irrigation vulnerable to drought. The same holds for less sophisticated types of irrigation, like spate irrigation or flood recession farming. Furthermore, the Inner Delta is a wetlands system in the West Niger Basin. This system contains a number of stakeholders: fishermen, livestock farmers and agricultural farmers. Additionally, it is a complex ecologic system, with flood forests, birds, fish and water mammals. All these interests benefit from a substantial flood wave causing inundation of large areas of the Inner Delta. The yearly maximum inundation is quite steady, irrespective of the hydrologic conditions. Considering these fields of interest, a river simulation model has been developed to indicate the competition between the interests claiming surface water. For every interest the demand is quantified and modelled as a diversion from the river. With a series of scenarios, different interest are given priority and climatic changes are simulated. Based on this model an analysis and evaluation of the power production, water supply for irrigation and the inundation of the Inner Delta is presented. This results in the identification of competition between interests with continuous water demand throughout the year (hydropower and fully managed irrigation) and interests with their water demand during the rainy season (controlled submersion irrigation and the Inner Delta stakes). For the latter, the water supply depends on the size of the Niger River’s flood wave. Additionally, there is a strong inducement to presume that interests depending on the flood wave are in competition with each other. Finally, this study reveals the uncertainty about the power production of the Fomi hydropower dam (which is under consideration), the level of inundation of the Inner Delta and their mutual impact. Several studies use out-dated or unreliable discharge data resulting in too extreme benefits and drawbacks. June 2008 III G.J. van Dijk Table of Contents 1. Introduction .............................................................................................1 1.1. Research context ................................................................................1 1.2. Geography .........................................................................................3 1.3. Socio-economics .................................................................................4 1.4. Water interests and allocation problems.................................................5 1.5. Research question...............................................................................6 1.6. Methodology ......................................................................................7 1.7. Limitations and Restrictions..................................................................8 2. Climatic and hydrological specifications ..................................................... 10 2.1. Climate............................................................................................ 10 2.2. Hydraulics........................................................................................ 11 2.3. Meteorology ..................................................................................... 12 3. Fields of Interest .................................................................................... 13 3.1. Hydropower ..................................................................................... 13 3.1.1. Power supply system .................................................................. 13 3.1.2. Selingué dam ............................................................................ 14 3.1.3. Sotuba station ........................................................................... 15 3.1.4. Fomi dam.................................................................................. 16 3.2. Irrigated agriculture .......................................................................... 17 3.2.1. Types of irrigation practice .......................................................... 18 3.2.2. Present irrigation schemes .......................................................... 20 3.2.3. Valuation of agricultural interest .................................................. 23 3.3. Inner Delta ...................................................................................... 25 3.3.1. Livestock................................................................................... 25 3.3.2. Fisheries ................................................................................... 27 3.3.3. Ecology..................................................................................... 28 3.3.4. Model data ................................................................................ 30 3.4. Other interests ................................................................................. 31 4. Simulation Model and Model Calibration..................................................... 32 4.1. Program choice and description .......................................................... 32 4.2. Model descriptions ............................................................................ 33 4.3. Model calibration..............................................................................