The modern dam
Basic problems in dam design
Most modern dams are of two basic types: masonry (concrete) gravity designs and embankment (earthfill or rockfill) designs. Masonry dams are typically used to block streams running through relatively narrow gorges, as in mountainous terrain; although the structures may be very high, the total amount of material required for such sites is limited. Embankment dams are often preferred to control rivers and streams passing through broad, wide valleys where only a very long barrier, requiring a great volume of material, will suffice. The choice of design depends on the geology and configuration of the site, the purposes of the dam, and cost factors related to material supply and site accessibility.