Historical framekwork on dams. General history of ancient dams, largest and historic failures of embankment dams

Abstract

Dams have practically been around since human civilization. While modern dams are built for hydroelectric purposes, ancient dams were built to flood prevention and water irrigation providing. In the past, the sparse knowledge on hydrology, soil mechanics and on structures analysis made the waterworks development to be based on empirical methods. Because of this, most of the dams were constructed indiscriminately with earth and rock, with no slope protections and were not provided with safety and discharge organs, being that floods were usually discharged in the middle of the dam, where crest elevation was lowered to act as a spillway. Consequently, the failure by overtopping was a frequent accident. At the present, dams are mostly built for the production of hydroelectric power, providing for 1/3 of irrigation water and 20% of electric power worldwide. Other utilities the use of impoundments confined by earth dams for storing and decanting tailings from mining activities. The construction of a dam usually upsets the valley’s environment, by submerging vast areas, and the morphologic features and river regime and flow rate. Take as example the Three Gorges Dam in China, where millions of inhabitants had to change their original settlements. Since the begging of human civilization dams have evolved across time, converging for the current extensive knowledge owned on these days. This work addresses an historical review on dams since the begging of human civilization until the present. As regards great engineering works of the last century, dams have been shown to be hazardous constructions in several cases, since dam failures have caused very serious damage and high casualty figures. This is even truer for embankment dams, since most of the fatalities caused from dam failures arrive from accidents with dams of this type. Accordingly, an overview on the present largest embankment dams and on the historic failures of this type of dams on the Modern Era are also approached.