Can integrated water resources management sustain the provision of ecosystem goods and services?

Society derives a wide array of important benefits from biodiversity and the ecosystems in which it exists. These ecosystem services are essential to human existence and operate on such an overarching scale, and in such intricate and little-explored ways, that most could not be replaced by technology. Accordingly, approaches to integrated water resources management (IWRM) do not regard the ecosystem as a "user" of water in competition with other users, but as the base from which the resource is derived and upon which development is planned. A goal of IWRM should be to maintain, and whenever necessary, restore ecosystem health and biodiversity. Achieving the sustainable use of water resources and thus the maintenance of ecosystem services requires a rediscovery of the hydrological cycle and the water resources system. Such a rediscovery could; . identify characteristics that are critical to the provision of ecosystem services with emphasis on biophysical, economic, social and environmental characteristics and linkages in the system, . provide improved understanding of the behaviour of the interactions of the system, leading to the ability to provide cause and effect predictions and ultimately, . manage the water resources system guided by both biophysical and socio-economic indicators, end-points and value systems applicable to this rediscovery. In this paper, the concept of an ecosystem approach to the management of water resources is assessed in the light of a reanalysis of the hydrological cycle. The approach to maintenance of ecosystem functioning in South Africa through the so-called Resource Directed Measures is considered in the light of this assessment. It is concluded that there is a danger that, traditional command and control approaches to management of the water resources system will continue to be applied under the banner of IWRM and that this will result in the failure of natural systems to sustain the provision of ecosystem goods and services. (C) 2002 Elsevier Science Ltd. All rights reserved.