100 Years of Embankment Dam Design and Construction in the U.S. Bureau of Reclamation

The design and construction of earthfill and rockfill embankment dams in the Western United States have evolved dramatically during the past 100 years (1902-2002). The U.S. Department of the Interior’s Bureau of Reclamation (Reclamation) has played a significant role in that evolution of embankment dam engineering, construction, and dam safety during the 20 Century. There are now over 240 water-storage embankment dams in the Western United States that were designed and constructed by Reclamation. The list of civil engineers and other professionals who have helped to design and build Reclamation’s embankment dams is lengthy and highly regarded. This paper discusses Reclamation’s embankment dam design and construction organizations and how they have evolved during the past century. Starting in 1902, Reclamation's embankment dam design and construction approach involved one engineer in charge of all phases of the work, from development of the project all the way through design and construction of the dam and appurtenant structures. Embankment dam design and construction were then based largely on previous experience with dams that had been successfully designed, built, and operated without failure. Since that beginning, the design of embankment dams has evolved to now include: site investigations and engineering geology; paleohydrology; evaluation of foundation conditions and treatment; laboratory investigations of foundation and borrow materials; geotechnical analysis of design criteria such as seepage, filters, slope stability, deformation, and seismic behavior; instrumentation and performance monitoring; and construction equipment, methods, and management. Reclamation's embankment dam design and construction history can be separated into five periods. Period I runs from 1902 to 1918; Period II extends from 1919 to 1933; Period III covers 1934 to 1944; Period IV includes 1945 through 1975; and Period V runs from 1976 to the Present (2002). In summarizing Reclamation’s embankment dam design and construction history, many of the notable embankment dams designed and constructed by Reclamation during each of those periods are discussed. The last 100 years have seen the design and construction of embankment dams develop from the relatively simple homogeneous or two-zone earthfill embankments designed at the beginning of the 20 Century into the extremely complex, highly analyzed, well-instrumented zoned earthfill and/or rockfill structures that are the embankment dams of the 21 Century. A central component of the evolution of engineering of embankment dams has been the birth and maturation of geotechnical engineering as a civil engineering specialty. The evolution in construction equipment during the past 100 years is also discussed in the paper. The development of Reclamation’s publications, such as the Earth Manual, Design of Small Dams, and the Design Standards, is also discussed. The near failure of Fontenelle Dam, the failure of Teton Dam, and the lessons learned from those events are discussed in the paper. And, the post-Teton changes in Reclamation’s embankment dam designs and in the organization are discussed.