It is becoming increasingly evident that the watershed is an appropriate scale for improved understanding of the dynamic processes in rivers and lakes (cf. Boon et al., 2000; Biswas & Tortajada, 2001). During recent years, this approach has for example been adopted in modern management tools such as the Water Framework Directive (WFD) of the European Union (EU, 2000), and in international environmental assessment exercises such as the Millennium Ecosystem Assessment (www.millenniumassessment.org; DN, 2002). The ‘ecosystem approach’ adopted by the Convention on Biological Diversity is also promoting a holistic watershed approach in biodiversity and resources management (Schei et al., 1999; www.biodiv.org). Consequently, management oriented research has to focus on watershed processes in order to provide the required information that needs to underpin future management.