Conceptual framework for the management of shared river basins; with special reference to the SADC and EU

Abstract

1. Shared river basins, an introduction 1.1. SADC and the EU Climatic diAerences stand out when comparing the regions of the European Union (EU) and the Southern African Development Community (SADC). Southern Africa has a distinct dry and wet season, and, more importantly, its climate is characterised by a high variation between relatively wet and dry years, a phenomenon much less pronounced in the EU. In addition overall evaporative capacity in the SADC region is considerably higher than in EU countries. In general, the SADC region is a water scarce area in comparison with Europe. For SADC countries water is key to sustainable development (IHE, 1994). Table 1 shows that many SADC countries are rapidly approaching situations of water stress (generally defined as less than 1700 m 3 per capita per year), if not absolute water scarcity (less than 1000 m 3 per capita per year) (Engelman & LeRoy, 1993; Gleick, 1993). A striking diAerence between EU and SADC countries is that the per capita water availability in the SADC region, which is already low, is expected to reduce by half by the year 2025, whereas per capita water availability in Europe remains virtually constant. The rapid decline in SADC countries is mainly a result of population growth. Data on per capita water availability suAer from lack of relevant hydrological information. Traditionally, the computations are based on the availability of surface water. The data of Gardner-Outlaw and Engelman (1997), in Table 1, also suAer from that bias. Other resources, in particular the amount of rainfall that is directly available for vegetation (termed ‘green’ Water Policy 2 (2000) 9‐45