Extending the Life of Reservoirs: Sustainable Sediment Management for Dams and Run-of-River Hydropower

Abstract

This book was developed to facilitate implementation of a programmatic approach using selected scientific methods for screening climate change and disaster risks, and integrating appropriate resilience measures into water, hydropower, and dam investment projects. As the World Bank Group steps up its activities in both the water and energy sectors, the risks of climate change and disasters need to be better understood and managed to ensure sustainable, resilient, and cost-effective outcomes. This increased awareness is particularly important for hydropower, water supply reservoir, and dam projects, given that climate change is projected to significantly affect water resources by changing mean annual river flows and hydrologic variability, thereby causing more extreme droughts and floods. For many countries, hydropower is now the largest source of affordable renewable energy . This is especially true in regions like Sub-Saharan Africa, South Asia, and Southeast Asia, which are characterized by significant untapped hydropower potential and water shortages.The remainder of this book is organized into nine chapters and an appendix: Chapter 2: Climate Change, Sediment Management and Sustainable Development discusses the importance of reservoir sediment management for preserving reservoir storage and illustrates how it contributes to satisfying the tenets of sustainable development. Chapter 3: Overview of Sedimentation Issues discusses the importance of reservoir storage and the impacts of reservoir sedimentation up- and downstream of dams. Chapter 4: Sediment Yield provides an overview of sediment yield, describes the important factors that determine the magnitude of sediment yield, and presents ways to estimate sediment yield. Chapter 5: Patterns of Sediment Transport and Deposition describes techniques for estimating the amount of sediment that will be deposited in a reservoir. Chapter 6: Sedimentation Monitoring discusses sedimentation monitoring procedures, bathymetric mapping of sediment, and estimation of sediment bulk density. Chapter 7: Sediment Management Techniques presents an overview of activities of combat reservoir sedimentation. Chapter 8: Sediment Management at Run-of-River Headworks describes basic concepts to consider in the design or rehabilitation of run-of-river headworks with regard to sediment management. Chapter 9: Reservoir Sustainability Best Practices Guidance summarizes sediment management strategies that will provide a higher level of assurance that the project operation can be sustained indefinitely. Appendix A: Checklist for Sediment Management is for use by project proponents to help ensure that projects adhere to the recommendations put forth throughout the book. The checklist is divided into three sections: sediment yield, sustainable sediment management measures, and sediment patterns and impacts.