Tolerable Risk Guidelines for Dams: How Safe is Safe Enough

Tolerable risk guidelines are used to guide the process of evaluating whether or not dam safety risks are low enough. They provide a means of relating dam safety risks to other risks to which people are exposed as a result of technological hazards. While these guidelines should not be used as the only basis for dam safety decisions, they can play a useful role in making the case for a decision.

This webinar will provide both examples of practical applications of USACE and Reclamation tolerable risk guidelines and a summary of the principles that underlie the basis for tolerable risk guidelines. The examples will be for existing dams and for the evaluation of risk reduction alternatives. They will be based on almost 20 years of experience with applying tolerable risk guidelines in several countries in support of real-world dam safety decisions.

Variations in dam safety tolerable risk guidelines in several countries will be discussed. Implementation issues such as considering uncertainty in risk estimates and practical ways to build legal defensibility through considering if risks have been reduced as low as reasonable practicable will be discussed. In addition, examples of tolerable risk guidelines will be provided from other fields such as environmental protection, nuclear safety, transportation safety and land-use planning.

Speaker and Presenter Information

David S. Bowles, Ph.D., P.E., P.H., D.WRE, F.ASCE

Since 1978 David and his colleagues have pioneered the development and practical application of risk-informed approaches to dam safety management. They have completed individual and portfolio risk assessments for more than 800 dams in many countries, ranging from screening assessments to detailed assessments with uncertainty analysis. David has assisted with the development of tailored frameworks for dam and levee safety risk management for government and private owners, regulators and professional bodies in many countries. Clients have included Reclamation, USACE, TVA, FERC, BIA, World Bank, WMO, IAEA, EPRI, EU, ANCOLD and NSW DSC. David has served as an expert witness for law suits related to dam and canal failures, reservoir operation and hydropower generation, toxic tort, and urban flooding.

Beginning in 1994, David has assisted Reclamation, USACE, ANCOLD, NSW DSC, the Environment Agency and Defra in the UK, and many other organizations with the development and application of tolerable risk guidelines for dam safety. He was the principal author of the sections on risk evaluation and risk management in ICOLD Bulletin 130 on dam safety risk assessment.

David has provided training programs on six continents and has authored or reviewed numerous guidance documents for dam safety risk analysis, assessment and management. He has led software development for dam risk analysis (DAMRAE) and life-loss estimation (LIFESim with a simplified version in HEC-RAS) for USACE, portfolio risk assessment for a large UK dam owner (ResRisk), and real-time reservoir flood operation for Reclamation, USACE and SAFCA.

David is the Managing Principal of RAC Engineers and Economists and an Emeritus Professor of Civil and Environmental Engineering at Utah State University (USU). Previous positions include Director of the Institute for Dam Safety Risk Management and Director of Utah Center for Water Resources Research at USU, Engineering Department Manager and Branch Manager for Law Engineering’s Denver office, and a construction and design engineer for a large international contractor based in the UK.

Home Page (including links to selected papers): http://uwrl.usu.edu/people/faculty/bowles.html
Email: David_S_Bowles@hotmail.com

Relevant Government Agencies

Army, Dept of Energy, Dept of Homeland Security, Dept of the Interior, Other Federal Agencies, State Government, County Government, City Government, Municipal Government, FEMA, Federal Government, State & Local Government