Title: Types of Dams
Course: 2016FA-MCO-115-401 > Section: Module 3: Dams

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Types of Dams
Photo | Name of Dam Type | Description
 | Arch Dams | Arch Dams are curved in an arch towards the water flow. According to Funk & Wagnall’s New World Encyclopedia, “the main water load [with arch dams] is distributed horizontally to abutments on the side walls of the narrow valley or canyon…” where the dam is built [3, p. 4]. While arch dams are built from concrete, most require less concrete than gravity dams. This dam requires a highly specialized set of circumstances in its location, and there are few of them in the United States. The strength of an arch dam comes from the arch itself and from gravity. The Milliken Dam in California and Flaming Gorge Dam in Utah are two examples of arch dams. Milliken Dam is used for drinking water, improved navigation, and the reservoir offers fishing and other recreational activities [6] [7]. The Flaming Gorge Dam has a hydroelectric power plant at its base [8]. One of the most famous dams in the United States, the Hoover Dam, is an example of an arch-gravity dam. It has the characteristics of both a gravity dam and an arch dam.
 | Buttress Dams | Buttress dams (also known as hollow dams or hollow gravity dams) utilize an upstream face or deck to support the impounded water, and multiple buttresses to support the deck. “A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall” [9]. Buttress dams are usually built in wide valleys and they can be made up of a combination of concrete and steel. Both flat slab and multiple arch architecture are used when designing buttress dams [10]. The strength of a buttress dam comes from the buttress’ support and redirection of pressure to the base of the dam. The Bartlett Dam on the Verde River near Phoenix, Arizona is an example of a multiple arch buttress dam [11].
Embankment Dams
Embankment dams can be made from clay, large rocks, and other natural materials. Because these materials are not very sturdy in a steep slope, an embankment dam is built with a wide base that is wider than the height. It is best suited for wide valleys and is more cost effective if built in an area that is rich in the resources used to make it (rocks, clay, et cetera) [3].

There are two types of embankment dams, the earthen dam (which is earth filled) and the rock-filled dam [12]. Earthen dams consist mainly of compacted earthen materials to form the embankment. There are variations on this architecture that can take advantage of locally available materials that are plentiful such as shells or that require water tight cores or facings [3].

Rock-filled dams generally utilize an upstream face made of concrete, masonry, wood, or similar material. Rock-filled dams are usually found in areas where the earth is rich with rock and stone [13].

The largest embankment dam in the United States is Fort Peck Dam in Montana which provides hydroelectric power generation, recreation, navigation, irrigation, and public water supply [14].
 | Gravity Dams | Gravity dams are low maintenance, high performance dams that are made of solid concrete. The stability of this type of dam comes from its sheer mass. An example of a gravity dam is The Grand Coulee Dam on the Columbia River in Washington State. It contains approximately 10 million cubic yards of concrete and was completed in 1942.
 | Temporary Dams | Temporary dams, also called coffer dams, or construction dams, are utilized to stop or divert the flow of water for a brief period of time. Typically tempororary dams are used to keep construction zones clear.