History of Rockfill DAM Construction

Part 1 summarized rockfill placement and compaction guidelines for mine structures, including dams and structure foundations. Part 2 for this article provides an historical perspective to rockfill dam construction. The historical record indicates 4 milestones in rockfill dam construction.

The first milestone included the use of low level hand placed rockfill dumps with timber facing on the upstream slope in the 1850’s for water storage and gold sluicing operations. The second milestone included a gradual increase in water storage dam heights to over 300 feet (100 m) high using thick dry and loose rockfill dump lift placement by trucks or draglines without compaction into the 1940’s. The third milestone included the use of high-pressure water jets and flooding techniques to wet and consolidate the thick loose rockfill dump lifts to achieve up to 85 percent of total dam settlement before reservoir filling from the 1940’s into the 1950’s. The fourth milestone included control of rockfill lift thickness with dozer spreading and roller compaction, in addition to documentation of rockfill gradation, moisture, and density in large-scale test fills from the 1960’s to the present day.