Water for people.pdf - WHO Thailand Digital Repository

4 5 0 / P I L O T C A S E S T U D I E S : A F O C U S O N R E A L - W O R L D E X A M P L E SSenegal River Basin, Guinea, Mali, Mauritania, SenegalTHE SENEGAL RIVER BASIN is located in West Africa, between latitudes10°30 and 17°30 N and longitudes 7°30 and 16°30 W. It is drained by the1,800 kilometre (km)-long Senegal River, the second longest river ofWest Africa, and its main tributaries, the Bafing, Bakoye and Faleme Rivers,which have their source in the Fouta Djallon Mountains (Guinea) or in Mali.General ContextMost of the Senegal River basin has a sub-Saharan desert climate,aggravated by more or less long periods of drought during the1970s. Access to sufficient quantities of good-quality water istherefore a particularly sensitive issue and absolutely crucial for thehealth of the population and the economy.Physical characteristicsThe Senegal River basin covers a surface area of about300,000 square kilometres (km 2 ). The high plateaux in northernGuinea represent 31,000 km 2 (11 percent of the basin), 155,000 km 2are situated in western Mali (53 percent of the basin), 75,500 km 2 arein southern Mauritania (26 percent of the basin) and 27,500 km 2 arein northern Senegal (10 percent of the basin). The basin has threedistinct parts: the upper basin, which is mountainous, the valley (itselfdivided into high, middle and lower) and the delta, which is a sourceof biological diversity and wetlands (see map 20.2). Topographical,hydrographic and climatic conditions are very different in these threeregions and seasonal temperature variations are extensive.Socio-economic characteristicsPopulationThe Senegal River basin has a total population of around 3,500,000inhabitants, 85 percent of whom live near the river. This figureincludes approximately 16 percent of the total populations of thethree OMVS member states – Mali, Mauritania and Senegal – plusthe population of the Guinean portion of the upper basin.Map 20.1: Locator mapAtlanticOceanWesternSaharaSENEGALSenegal River basinGAMBIAGUINEA- GUINEABISSAUMAURITANIAMOROCCOMALIBURKINAFASOSIERRA LEONE COTED'IVOIRELIBERIAALGERIANIGERGulfof GuineaSource: Prepared for the World Water Assessment Programme(WWAP) by AFDEC, 2002.Table 20.1: Hydrological characteristics of the Senegal River basinSurface area of the basin 300,000 km 2Annual precipitation660 mm/yearAnnual runoff (Bakel station)Before 1985 698 m 3 /sAfter 1985 412 m 3 /sAnnual discharge (Bakel station)Before 1985 863 m 3 /sAfter 1985 416 m 3 /sThe population within the basin is increasing at a rate of about3 percent per year, which is slightly higher than the individualaverages for the three member states.A large ethnic diversity also characterizes the basin’s population,with, among others, Peuls, Toucouleurs, Soninkes, Malinkes,Bambaras, Wolofs and Moors. However, there is massive emigrationamong the young towards the major cities and to Europe.Table 20.2: Summary of physical dataMali Mauritania Senegal GuineaSurface area (km 2 ) National 1,248,574 1,030,700 197,000 245,857Basin 155,000 75,500 27,500 31,000(% of basin) 53 26 10 11Rainfall National 850 290 800 2,200annual average (mm) Basin 300 to 700 80 to 400 150 to 450 1,200 to 2,000Temperature National average 29 28 29 26Basin min. and max. 15 to 42 18 to 43 17 to 40 10 to 33Half of the basin is located in Mali, but the main input in terms of water resources comes from the upper basin in Guinea with an average of 1,600 mm of precipitation.