Scenario Development for Water Resources Planning and Management

Scenario analysis is a process of evaluating possible future events through the consideration of alternative plausible (though not equally likely) outcomes (scenarios). The analysis is designed to enable improved decision-making and assessment through a more rigorous evaluation of possible outcomes and their implications. For environmental impact assessment studies, the process of scenario development typically involves making explicit and/or implicit assumptions about potential future conditions, such as climate change, land cover and land use changes, population growth, economic development, and technological changes. Realistic assessment of scenario impacts often requires complex integrated modeling frameworks that represent environmental and socio-economic systems to the best of our knowledge, including assumptions about plausible future conditions. In addition, scenarios have to be developed in a context relevant to the stakeholders involved, and include estimation and communication of uncertainties, to establish transparency, credibility, and relevance of scenario results among the stakeholders. This paper reviews the state-of-the-art of scenario development and analysis, proposes a formal approach to scenario development in environmental studies, discusses existing issues, and makes some recommendations for future research in this area.