Assessing the Safety of Existing Embankment Dams

Many existing embankment dams were designed and constructed to standards below current requirements, potentially posing risks to downstream populations. Dam owners must assess whether these structures provide adequate safety or require upgrades to reduce risks to acceptable levels. This book provides in-depth analysis of dam failure mechanics alongside relevant engineering assessment methods.

The book provides comprehensive methods for assessing embankment dam safety across four critical failure modes: overtopping, slope instability, deformations under seismic loading, and internal erosion and piping. Assessment approaches include deterministic (standards-based), risk-enhanced deterministic, quantitative risk assessment (QRA), and simplified QRA methodologies. These approaches represent current industry practice, drawing from the author's extensive experience in dam safety assessment and upgrade design across more than 200 dams in Australia, New Zealand, Canada, the USA, and Panama.

The book is designed to help dam owners, their consultant engineers, and engineering geologists develop defensible safety assessments and upgrade designs for existing dams.

Robin Fell has 58 years of experience in dam engineering, geomechanics, landslides and slope stability, applied to a wide range of projects and in several countries. This has involved work in Papua New Guinea, Fiji, Solomon Islands, Hong Kong, Thailand Tanzania, New Zealand, Canada, Panama and USA, as well as throughout Australia. He has specialised in embankment dam engineering, geotechnical engineering of dams and associated structures, and risk assessment for dams and landslides. He has worked on over 150 dams, and a further 100 dams in portfolio risk assessments. He worked for 10 years with the Australian Government on Hydropower projects, and 10 years with consulting Geotechnical Engineers before being appointed Professor of Geotechnical Engineering at UNSW in 1985. There he supervised research into internal erosion and piping of embankment dams, and risk assessment of dams and landslides. He has consulted on peer review panels for dams throughout Australia, and in Canada, USA, Panama and New Zealand. He is acknowledged internationally for his expertise in internal erosion and piping of dams, and risk assessment for dams and landslides. He was the lead author of the book Geotechnical Engineering of Dams, published by Taylor & Francis, and ICOLD Bulletin 164 on Internal Erosion of existing dams, levees and dikes and their foundations.

Mark Foster has 30 years of experience in geotechnical and dam engineering, with specialist expertise in dam safety upgrade design, embankment dams and risk assessment. He has conducted independent review of dam safety assessments for existing dams and new dams. He is an active member of the Australian National Committee on Large Dams (ANCOLD) and was on the working group who completed updating of the guidelines on risk assessment for dams. He completed his doctorate in 1999 under the supervision of Professor Fell at UNSW, titled “Methods for Estimating the Probability of failure of Embankment Dams”. He is a co-author of the widely referenced book “Geotechnical Engineering of Dams” published by Taylor & Francis.

Gavan Hunter has more than 30 years of experience in geotechnical engineering for a range of water, civil and mining projects. He specialises in geotechnical dam engineering and has been involved with the assessment of performance, investigation, design and construction of upgrades for numerous dam projects in the past 20 years. These projects have covered a broad range of geotechnical engineering application including soft ground engineering, slope stability assessment, risk assessment, foundation design, assessment of performance (deformation, seepage, pore pressure), cut-off wall design, liquefaction assessment, earthworks control, and design and construction advice. Embankment types have included water storage and tailings dams, and range in size from small dams up to very large dams, including some of Australia’s most significant dams. For the past 5 years, he has provided independent technical review to water authorities and mining companies on a range of dam projects, mostly in Australia but also internationally. He completed his doctorate in 2003 under the supervision of Professor Robin Fell, titled “Pre and Post Failure Deformation Behaviour of Landslides in Soil Slopes”. He represents ANCOLD on the ICOLD Embankment Dams Committee (Committee E).

Chi Fai Wan has over 30 years of post-graduate experience, principally in the field of water and dams engineering. He has specialist skills regarding internal erosion of embankments, having researched aspects of initiation of piping erosion and soil erosion rate. He has published more than thirty technical papers and reports on soil erosion testing, dam design, risk assessment, probabilistic design and analysis, numerical modelling, and internal erosion in dams, and was a guest lecturer in Dams Engineering Courses at the Sydney University and the University of New South Wales. He has worked as a numerical modeller, design engineer, risk analyst, and specialist in internal erosion problems for dam consultants in Australia, Hong Kong, and the USA. He has served as design manager for dam raising and safety upgrade projects, and as technical lead in numerous dam safety reviews using both traditional and risk assessment methods.