A training seminar being taught across the US is giving engineers an introductory grounding in dam safety and rehabilitation, writes Andy Yung and Chris Johnson
Dodson & Associates, Inc. of Houston, Texas, US has developed a two-day dam safety and rehabilitation course for the American Society of Civil Engineers (ASCE). It was conceived as part of a series of seminars created by ASCE on declining infrastructure in the US. Dodson & Associates has provided teaching support for a number of ASCE seminars in the past, including seminars on hydraulic modelling, hydrologic modelling, flood plain management and storm water quality. With this background, ASCE requested that Dodson & Associates develop a seminar on dam safety that could be taught nationwide.
With ageing infrastructure becoming more and more a focus of serious attention in the US, concerns over the nation’s dams are beginning to arise. Many involved with the design, operation and maintenance of dams may not realise their legal responsibilities. Who is responsible for maintaining existing dams? What are the causes of a dam failure? What are the consequences of a failure? Who is responsible if a dam fails? What can be done to prevent failure? How is a dam inspection performed?
The seminar is taught several times per year in different cities across the US. The seminar is a two-day course designed to inform engineers, dam owners and operators about the potential risks and responsibilities associated with ageing dams, while at the same time providing some technical information necessary for evaluating those risks and responsibilities. The objectives of the seminar are to identify the current status of existing dams in the US, to learn the basic fundamentals of performing a dam safety inspection, to learn how to evaluate the safety of existing dams and to identify various rehabilitation practices.
Topics covered in the seminar can generally be categorised into five main parts.
• A history of dams, which begins with a brief description of the various reasons that dams have been built. Then there is a fairly extensive chronological history of significant dams dating back to the third millennium B.C. The section ends with a discussion on the various types of dams and outlet works which are in use today. This section provides a basis from which all others can continue discussion.
• An overview of dam safety criteria in the US. This section contains a discussion of issues facing existing dams, including a brief comparison of several state dam safety programmes and their funding. This leads into a discussion of the legal aspects associated with dam safety including the liabilities of dam ownership, federal legislation related to dam safety and hazard classification/dam safety criteria.
• Information related to the consequences of dam failure, including information about the various modes of failure and some historical information regarding several notable dam failures.
• Information necessary for the determination of the safety of existing dams. Included in this section is a description of inspection procedures, a description of the types of deficiencies that may be encountered during an inspection, a discussion of hydrologic analyses related to dam safety and potential dam failure, and an overview of emergency action planning.
• Developing basic techniques of rehabilitating ageing dam structures. This section incorporates data from the National Resources Conservation Service (responsible for the construction of many dams across the US), several case studies, an overview of potential remedies for problems found during inspection and a discussion on dam security in the twenty-first century.
The course includes several workshops intended to encourage discussion among peers and enable the attendees to better understand how some of the information presented can be applied. In addition, the discussion of the deficiencies associated with existing dams is designed to be more interactive by dividing the attendees into groups to identify the causes of various deficiencies and why these deficiencies are a concern for the dam owner.
Where available, a representative of the state dam safety agency responsible for administering dam safety criteria in the particular state where the seminar is being taught is invited in to speak for up to an hour on their state’s regulations regarding existing and proposed dams. This allows attendees to interact with a dam safety official and to better understand the various rules in place to provide oversight for dams while providing the attendees a comparison with their own state’s rules and regulations regarding dams.
Attendees receive additional take-home material from the course, including handouts, an inspection checklist and a list of references for further study and research.
Attendees and goals
As the course is only two days long and covers such a wide range of topics associated with dam safety, it is impossible to go into a great amount of detail on any one particular topic. However, this format does provide an avenue for introducing information to people of varying technical levels. In fact, it should be considered an introductory course in dam safety and rehabilitation. While it is unlikely that engineers who have a significant degree of experience in dam safety will garner anything new, for engineers starting out in this field it should provide an excellent base of knowledge for future practice.
Although this course is offered through ASCE and is (for the most part) likely to draw civil engineers, it is designed to meet the needs of the many different types of people involved with dam safety. Consulting engineers will have current and concise information to assist their clients. Public officials will be able to manage local efforts and/or consultants more effectively. Owners, supervisors, and operations and maintenance representatives will have a more comprehensive knowledge of risks posed by dams that will enable them to better manage and operate facilities under their day-to-day responsibility. With this wide array of participant credentials, it is noted that while some mathematical background is encouraged, it is not required.
It is the goal of this course to have participants leave with a better understanding of the principles necessary to identify and mitigate the risks associated with a potential dam failure. It is intended that attendees will better understand federal, state, and local safety criteria governing existing dams; have a knowledge of the procedures necessary to perform a reasonable inspection of an existing dam; be able to identify methods of performing dam safety and dam failure analyses; and better understand the efforts necessary to mitigate the risk of dam failure through rehabilitation of existing infrastructure.
With a myriad of dams across the US approaching or surpassing their life expectancy, and many dam owners unaware of the liabilities involved with a failure of a dam, it is the aim of this course to provide information to engineers, public officials responsible for dams, and dam owners and/or their representatives related to dam safety and rehabilitation. It is intended that this seminar raise awareness regarding dam safety issues while providing basic necessary information related to potential problems and solutions to those who work with dams.
ASCE conducts evaluations of each of their courses, which enable attendees to respond openly about the course topic, material, and instructor. Thus far, the course has generally received a favourable response from participants.
The cost of the course is US$995 for ASCE members and US$1195 for non-members. In addition, the course is offered on CD-ROM through ASCE’s distance learning programme at a cost of US$295 for ASCE members and US$345 for non-members.Andy Yung and
Chris Johnson are senior hydrologists with Dodson & Associates, and are responsible for the ASCE dam safety and rehabilitation training course. Email: AYung@Dodson-Hydro.com