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The Senegal River Basin and Related Data Sources

KEY GEOGRAPHIC AND HYDROLOGICAL FEATURES OF THE SENEGAL RIVER BASIN

The Senegal River is formed by the confluence of two smaller rivers, the Bafing and Bakoye, which occurs near Bafoulabé, Mali, at about 1,083 km from the Atlantic Ocean.1 After crossing western Mali, the Senegal River constitutes the boundary between Senegal and Mauritania. The Senegal River basin (SRB) occupies a total area of 289,000 km2. It includes three main regions—the upper basin, valley, and delta—with each region clearly characterized by distinct environmental conditions. Figure 2.1 provides a cartographic depiction of the basin.

As might be expected the flow rate of the river is determined mainly by the rainfall in the upper basin. The high-water season lasts from July to October; the low-water season, with a steady decrease in volume, begins in November and lasts until May or June. The high-water season peaks at the end of August or beginning of September and quickly ends during October.

Another important feature of the Senegal River prior to the construction of its two dams was the inter-annual irregularity in its flow volume. For a long time this inter-annual flood irregularity posed a major problem for the valley, as it decreased the potential for guaranteed agricultural production in this narrow geographic area. The arable land area that could effectively be farmed after the

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The description of the Senegal River basin and the OMVS in this section is based on the OMVS report Pour une gestion durable des ressources naturelles et de l’environnement du bassin du Fleuve Sénégal, December 2001, OMERIS Communication, Dakar, Senegal.



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2 The Senegal River Basin and Related Data Sources KEY GEOGRAPHIC AND HYDROLOGICAL FEATURES OF THE SENEGAL RIVER BASIN The Senegal River is formed by the confluence of two smaller rivers, the Bafing and Bakoye, which occurs near Bafoulabé, Mali, at about 1,083 km from the Atlantic Ocean.1 After crossing western Mali, the Senegal River constitutes the boundary between Senegal and Mauritania. The Senegal River basin (SRB) occupies a total area of 289,000 km2. It includes three main regions—the upper basin, valley, and delta—with each region clearly characterized by distinct environmental conditions. Figure 2.1 provides a cartographic depiction of the basin. As might be expected the flow rate of the river is determined mainly by the rainfall in the upper basin. The high-water season lasts from July to October; the low-water season, with a steady decrease in volume, begins in November and lasts until May or June. The high-water season peaks at the end of August or beginning of September and quickly ends during October. Another important feature of the Senegal River prior to the construction of its two dams was the inter-annual irregularity in its flow volume. For a long time this inter-annual flood irregularity posed a major problem for the valley, as it decreased the potential for guaranteed agricultural production in this narrow geographic area. The arable land area that could effectively be farmed after the 1   The description of the Senegal River basin and the OMVS in this section is based on the OMVS report Pour une gestion durable des ressources naturelles et de l’environnement du bassin du Fleuve Sénégal, December 2001, OMERIS Communication, Dakar, Senegal.

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FIGURE 2.1 Senegal River Basin. Source: Kristine McElwee, 2000. Complementing Data: Elements of Decision-Making for Natural Resource Management in the Senegal River Basin. Master’s Thesis.

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flood could vary between 15,000 ha and 150,000 ha, depending on the magnitude and duration of the flood. Exceptionally high water levels caused widespread devastation in 1890, 1906, and 1950. Conversely, the years with extremely reduced water flow were also disastrous, since they did not yield a sufficient agricultural production in the valley. Most recently the drought of 1972-1973 was particularly devastating for the populations and the economy of the riparian region. During the low-water discharge period, from November to May or June, no significant rainfall occurred, and the river discharge and that of its tributaries gradually decreased. The particularly low water level during the dry season resulted in a deep intrusion of the ocean’s salted waters into the riverbed. During the 1970s a saltwater wedge penetrated more than 200 km upstream of Saint-Louis. To address the problems associated with the significant inter-annual variability in rainfall and water flow of the Senegal River, three of the four main bordering countries—Mali, Mauritania, and Senegal—entered into a treaty to form the Senegal River Authority, the Organisation pour la Mise en Valeur du Fleuve Sénégal (OMVS), and related organizational structures in 1972.2 The tasks of the OMVS were to attain the goal of food self-sufficiency for the SRB inhabitants; reduce the economic vulnerability of the organization’s member states to climatic fluctuations as well as to external factors; accelerate the economic development of member states; conserve ecosystem balance in the sub-region, particularly in the basin; and secure and improve the incomes of basin inhabitants. To accomplish these goals the OMVS was charged with constructing and managing a regional infrastructure consisting of two major dams and related facilities and structures. The Diama Dam was the first to be completed, in 1986, near the mouth of the river at Saint-Louis. The primary goal of this dam was to stop the saltwater intrusion upstream and to make the delta’s land suitable for agriculture. The workshop participants were able to visit this dam and to see its operations first hand. The Manantali Dam was completed a year later as a reservoir dam with multiple purposes, including retention of about 11.3 billion m3 of water; regularization of river flows to 300 m3/s at Bakel; irrigated culture development in the downstream valley region; continuous river navigability; and energy production at the power station at the bottom of the dam. The hydroelectric power station, which was completed last year, includes generators that produce 800 GWh/year, 2   Prior to the organization of the OMVS the four border countries—Guinea, Mali, Mauritania, and Senegal—belonged to the Organisation des Etats Riverians du Fleuve Sénégal (or the Senegal River Riparian States Organization), which managed the river basin. This organization dissolved when Guinea withdrew due to political tensions. The three remaining countries subsequently created the OMVS.

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guaranteed 9 out of 10 years, and a 1,500-km transport line network to assure energy delivery to interconnected networks in the three member states. Still under development is a navigable channel from the mouth of the river over 900 km upstream to enable ships to access landlocked Mali, and the Mauritanian southwest and the Senegalese northeast regions. This part of the project also includes construction of a river port in Saint-Louis and seven smaller ports upstream. Two private holding companies are now responsible for the management, operation, and maintenance of the dams. The Société de Gestion et d’Exploitation de Diama (SOGED, or the Diama Dam Management Company) and the Société de Gestion de l’Energie de Manantali (SOGEM, or the Manantali Energy Management Company) were created in 1997, and are located in Mauritania and Mali, respectively. There are several other organizations within OMVS that have various responsibilities regarding the dams. The OMVS Regional Documentation Center is located in Saint-Louis and processes and archives the many documents and data related to the activities of the OMVS, mostly administrative materials. It also provides access to these materials currently only in paper form, and hosts and maintains the OMVS Web site, where a directory of its archived documents is being made available. In 1998 the OMVS created the Programme d’Attenuation et de Suivi des Impacts sur l’Environnement de l’OMVS (PASIE, or Environment Impact Mitigation and Monitoring program), which conducts environmental impact mitigation and monitoring activities related to the development of the dams. It receives financing from the World Bank and the African Development Bank, as well as France and Canada. PASIE consists of six programs focused on construction impact mitigation and monitoring; appropriations and right of way for transmission lines; reservoir management; environmental health; associated measures; and monitoring, coordination, and communication. In May 2000 OMVS established the Observatoire de l’Environnement, or Environmental Observatory. The main objective of the observatory is to monitor environmental change in the SRB as part of PASIE’s coordination and monitoring program in order to provide required information for measuring environmental impacts of dams and hydraulic development to the OMVS high commissioner, the three member states, and to various OMVS partners to enable decision makers and populations to implement actions that would ease negative impacts on the environment.3 3   The workshop participants did not receive a briefing on or visit the Environmental Observatory. For more information about the Observatory and PASIE see OMVS. 2001. Pour une gestion durable des ressources naturelles et de l’environnement du bassin du Fleuve Sénégal.

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SELECTED SCIENTIFIC DATA SOURCES RELATED TO THE SENEGAL RIVER BASIN There are many other sources of scientific data relating to the SRB in addition to the OMVS and related organizations that are directly responsible for the oversight, management, and maintenance of the dams and that monitor the environmental issues in the basin. These sources are very diverse, ranging from national and regional sources to international ones, including nongovernmental organizations. Other river systems also provide useful data for comparative analysis. This is not a comprehensive list of data sources for the basin but a pointer to organizations that were identified during the course of the workshop that either collect or disseminate relevant data.4 National Data Sources5 Senegal Within the government of Senegal, there are several ministries that focus on environmental, natural resource, and health issues, and therefore conduct work related to the SRB. (Information regarding the relevant ministries can be found on the Senegal government Web site.6) These include the Ministère de la Jeunesse, de l’Environnement et de l’Hygiène Publique (Ministry of Youth, Environment, and Public Hygiene), the Ministère des Mines, de l’Energie et de l’Hydraulique (Ministry of Mines, Energy, and Hydrology), the Ministère de la Santé et de la Prévention (Ministry of Health and Prevention), the Ministère de la Pêche (Ministry of Fishing), and the Ministère de l’Agriculture et de l’Elevage (Ministry of Agriculture). The Senegalese government also created the Conseil Supérieur des Ressources Naturelles et de l’Environnement (CONSERE, or the Higher Council for Natural Resources and the Environment) and the Commission Nationale pour le Développement Durable (the National Commission on Sustainable Development) to oversee and coordinate environmental policy. The Centre de Suivi Ecologique (CSE), or the Ecological Monitoring Center, located in Dakar, is a remote-sensing and GIS data center. It is part of the 4   An alphabetized list of organizations and their contact information, where available, is in Appendix C. 5   The participants at the workshop did not receive a briefing on all of the national sources of S&T data in the four border countries. This information was culled from workshop presentations and various Web sites, including those of the Senegalese and Mauritanian governments, as well as the “Senegal River Basin Water and Environmental Management Project—Project Brief” (2001, World Bank and UNDP), which can be found at http://www.gefweb.org/Documents/Council_Documents/GEF_C18/Regional_Senegal_River_Basin.pdf. 6   See the Web site of the Senegalese government at http://www.gouv.sn/ministeres/index.html.

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Ministry of Youth, Environment, and Public Hygiene, and also partners with the U.N. Development Programme, the private sector, and local authorities, among others. CSE both collects and provides data for a variety of applications and services for Senegal and the sub-region. For example, to collect data and monitor the environment it uses foreign remote-sensing sources (National Oceanographic and Atmospheric Administration [NOAA]/Advanced Very High Resolution Radiometer [AVHRR], Système Probatoire pour l’Observation de la Terre (SPOT), Landsat Thematic Mapper, and Meteosat), aerial surveys, and field work. CSE also produces a variety of data products and services. These include monitoring plant production using the normalized difference vegetation index (NDVI) derived from NOAA/AVHRR data, estimating rainfall using a Meteosat-based model, evaluating agricultural production using diverse satellite imagery, and monitoring bushfires using NOAA imagery. CSE also provides land-use and land-cover mapping services, low-altitude aerial surveys, and training. Many of the workshop participants visited the CSE and received presentations on CSE data acquisition and environmental-monitoring activities, as well as on applications of GIS on land cover and natural resource management. Other national organizations in Senegal, both quasi-governmental and private, collect and provide data sources about the SRB. The Société d’Aménagement et d’Exploitation du Delta du Fleuve Sénégal (SAED), or the Society for the Development and Exploitation of the Delta, has the responsibility for the development of the left bank of the Senegal River. The Institut Sénégalais de Recherches Agricoles (ISRA, the Senegal Agricultural Research Institute) carries out agricultural research studies. The Centre de Recherches Océanographiques Dakar-Thiaroye (CRODT), or the Oceanographic Research Center Dakar-Thiaroye, is a research center affiliated with ISRA. The private Institut Pasteur de Dakar focuses on biological research, primarily on infectious diseases, and its applications to public health. Several universities in Senegal also conduct research in the basin. These include the Université Gaston Berger de Saint-Louis, which works closely with the OMVS in Saint-Louis, and the Université Cheikh Anta Diop, which was formerly the University of Dakar. The Institut de Santé et Développement (Health and Development Institute), which is a cooperative effort of Université Cheikh Anta Diop and Senegal’s Ministry of Health, and the Ecole Inter-Etats des Sciences et Medecine Vétérinaries de Dakar (the Interstate School of Science and Veterinary Medicine) are active in biomedical, health, and animal research. Mauritania In Mauritania the Conseil National pour l’Environnement et le Développement Durable, or the National Council for the Environment and Sustainable Development, has oversight responsibility for creating a national environmental

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strategy. Primary responsibility for the environmental development of the Senegal River rests with the Ministère de la Santé (Ministry of Health) through the Direction de la Planification et la Coopération Sanitaire (Office of Planning and Sanitary Cooperation) and the Ministère du Développement Rural (Ministry of Rural Development) through its Direction Nationale de l’Aménagement Rural (National Office of Rural Exploitation), as well as the Société Nationale de Développement Rural (SONADER, or the National Society for Rural Development). The Ministère de l’Hydraulique et de l’Energie (Ministry of Hydrology and Energy) has oversight for the generation of hydroelectric power and the Manantali Dam. Information about the relevant ministries in Mauritania can be found on the Web site of the Mauritanian government.7 Mali The Ministère de l’Environnement’s Direction de la Conservation de la Nature and the Direction du Contrôle des Pollutions et des Nuisances (Ministry of the Environment’s Offices of Conservation and of Pollution Control and Nuisances) and the Secrétariat Technique Permanent (Permanent Technical Secretariat) focus on the environmental management in Mali. However, the Ministère de l’Agriculture (Ministry of Agriculture) and the Ministère des Mines, de l’Energie, et de l’Eau (Ministry of Mines, Energy, and Water) have primary responsibility for the management of the Senegal River basin through their Direction Nationale de l’Aménagement et de l’Equipement Rural (National Office of Rural Exploitation and Equipment) and the Direction Nationale de l’Hydraulique et de l’Energie (National Office of Hydrology and Energy), respectively. Guinea In the Republic of Guinea the Ministère de l’Equipement (Ministry of Equipment) is responsible for environmental policy through its Direction de l’Environnement (Office of the Environment). Other organizations involved include the Ministère des Ressources Naturelles et de l’Energie (Ministry of Natural Resources and Energy) through the Direction Nationale de la Gestion des Ressources en Eau (National Office of Water Resource Management) and the Direction de la Métérologie (Office of Meteorology), and the Ministère de l’Agriculture, des Eaux et des Forêts (Ministry of Agriculture, Water, and Forests) through its Direction Nationale des Eaux et Forêts (National Office of Water and Forests). The Ministère des Mines, de la Géologie et de l’Environnement (Ministry of Mines, Geology, and the Environment) also plays a role in the environmental management of the upper basin. 7   See the Web site of the Mauritanian government at http://www.mauritania.mr.

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United States A number of U.S. government agencies collect and provide scientific and technical data and information relevant to the Senegal River basin. These include the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration, the EROS Data Center of the U.S. Geological Survey, the U.S. Department of Agriculture Foreign Agriculture Service, the National Institutes of Health, the U.S. Agency for International Development (USAID), and the Central Intelligence Agency. For example, the International Program at the EROS Data Center applies remote-sensing, GIS, and information delivery systems to meet international and developing country needs. Two of their current projects focus on West Africa. One monitors land use and land cover changes in the Sahel and the other is a prototype pilot project in Senegal looking at carbon sequestration in soil organic matter in Africa. Another example is the Africa Desk at NOAA’s Climate Prediction Center. The Africa Desk provides short-term climate monitoring and predictions for Africa, including expert assessments of rainfall outlooks; daily, weekly, monthly, and seasonal analyses; and model forecasts and satellite images. Guinea, Mali, and Senegal are participating countries. Some U.S. federal agencies have field offices in the region; for example, USAID has an office in Dakar. Many agencies have partnered with various organizations within the region, including the CSE. In addition to these significant federal sources of data, other U.S. organizations and universities conduct research in and/or collect relevant data and information about the SRB. For example, the Institute for Development Anthropology is a nonprofit, nongovernmental organization that has been collecting data about the basin and the impacts of the dams for many years. It has one of the most extensive archives of information about the area. There are also a number of universities that have relevant programs, including, for example, Michigan State University, Colorado State University, Louisiana State University, University of Arizona, and the University of California at Santa Barbara. Other Countries Many other countries outside Africa have organizations, both public and private, that conduct research and collect data relevant to the SRB, although the listing here is far from comprehensive. In particular, there are many French organizations that are still very active in the region. The Institut Français de Recherche pour le Développement (IRD, or French Research Institute for Development), formerly known as Orstom, is a long-established research organization funded by the French government; it has branches in Senegal, Guinea, and Mali. Germany also has a presence in the basin with the Deutsche Gesellschaft fur Technische Zusammenarbeit, or GTZ, which is a government organization that

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promotes international technical cooperation. Denmark, Canada, and many other countries are also active in the SRB, either through direct support of research organizations or through partnerships with international and nongovernmental organizations. Regional Data Sources The Comité Inter-Etats de Lutte contre la Sécheresse au Sahel (CILSS), or the Permanent Interstate Committee for Drought Control in the Sahel, is an organization of nine West African countries: Burkina Faso, Cape Verde, Gambia, Guinea Bissau, Mali, Mauritania, Niger, Senegal, and Chad. The Centre Régional AGRHYMET, or the Regional Center for Training in Agriculture, Hydrology, and Meteorology, is the remote-sensing and training center associated with CILSS. The Institut du Sahel is also part of CILSS and is responsible for the coordination and promotion of scientific and technical research in the Sahelian countries. Other regional organizations include the Economic Community of West African States and the Union Economique et Monétaire Ouest-Africaine (West African Economic and Monetary Union). The African Development Bank has financed a number of projects in the SRB, including PASIE and hydroelectric power generation at Manantali Dam. Another relevant regional organization is EIS-Africa, which is an environmental information management network in Africa. This cooperative program is focused on using GIS tools and applications to promote access to and use of environmental information for decision making. International Data Sources Many of the United Nations specialized agencies have a strong presence in the SRB, including the U.N. Development Programme (UNDP), the U.N. Environment Programme (UNEP), the Food and Agricultural Organization, the World Health Organization, and the U.N. Educational, Scientific, and Cultural Organization. All of these agencies are partners with various national and regional organizations in the SRB area and participate in a number of initiatives in the basin. For example, UNEP is a partner with the Senegalese Ministry of Mines, Energy, and Hydrology and DHI Water and Environment (an independent Danish consulting and research organization) in a pilot project that is looking at the environmental impacts of the Diama Dam in the Senegal River delta. Other international and nongovernmental organizations and projects are active in the region as well. The Global Environment Facility (GEF, or Fonds pour l’Environnement Mondial), which is implemented by the UNDP, UNEP, and the World Bank, has several projects in the basin. One will focus on SRB water and environment management. The objective of this GEF project “is to provide a participatory strategic environmental framework for the . . . sustainable development of the Senegal River basin and to launch a basin-wide cooperative program

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for transboundary land-water management” through capacity building, data and knowledge management, transboundary diagnostic analysis and a strategic action program, priority actions through pilot projects, and public participation and awareness.8 Another organization is the Observatoire du Sahara et du Sahel, which is an independent organization comprising African and European member states, as well as nongovernmental organizations, that promotes cooperation against desertification and poverty in Africa; Senegal, Mali, Mauritania, and Guinea are all members of this organization. ENDA Tiers Monde (or Environment and Development Action in the Third World) is a nonprofit organization promoting environmental development in developing countries and is headquartered in Dakar. The World Conservation Union (IUCN, previously the International Union for the Conservation of Nature) is also very active in the region. The IUCN is a nongovernmental environmental organization. For example, the IUCN coordinated the stakeholder involvement and participation in the GEF regional project through a series of workshops in Senegal, Mali, Mauritania, and Guinea. Other River Systems Within West Africa there are two organizations that provide examples of work being done on other river systems. The Organisation pour la Mise en Valeur du Fleuve Gambie (OMVG) is the Gambia River Authority. This organization, which was established in 1978, is similar to the OMVS, and involves Senegal, Gambia, Guinea Bissau, and Guinea; it is headquartered in Dakar, Senegal. The Niger River also originates in Guinea, and the Autorité du Bassin du Niger (ABN), or the Niger Basin Authority, was created in 1971. Its members include Benin, Burkina Faso, Cameroon, Chad, Ivory Coast, Guinea, Mali, Niger, and Nigeria. The U.S. Tennessee Valley Authority served as a model for the development of the ABN and the OMVG, as well as for the OMVS. 8   See “Senegal River Basin Water and Environmental Management Project—Project Brief,” 2001. World Bank and UNDP. The project brief and its cover memo from Lars Vidaeus, GEF Executive Coordinator, to Ken King, Assistant CEO, GEF Secretariat, on the project and its submission for work program inclusion, dated September 21, 2001, can be found at http://www.gefweb.org/Documents/Council_Documents/GEF_C18/Regional_Senegal_River_Basin.pdf. The workshop participants did not receive a briefing on this project.