Seimare Dam is an under construction arch dam

Arch dam

An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...

 on the Seimare River

Seimare River

The Seimare is a river in southwestern Iran formed by the confluence of the Ghareh Soo and Gamasyab Rivers. The Seimare Dam is located on its lower course before its confluence with the Karkheh River....

 in Darrehshahr County

Darrehshahr County

Darreh Shahr County is a county in Ilam Province in Iran. The capital of the county is Darreh Shahr. At the 2006 census, the county's population was 56,346, in 11,487 families. The county is subdivided into three districts: the Central District, Badreh District, and Majin District...

, Ilam Province

Ilam Province

Ilam Province is one of the 31 provinces of Iran. It is in the south-west of the country, bordering Iraq. Its provincial center is the city of Ilam. Covering an area of 19,086 square kilometers, the cities of the province are Ilam, Mehran, Dehloran, Dareh Shahr, Sarable, Eyvan, Abdanan and Arkwaz...

, Iran

Iran

Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...

. The primary purpose of the dam is hydroelectric power generation. Studies for the dam were carried out in the mid to late 1970s and construction began on the diversion works in 1997. In 2006, concrete placement began and on 19 May 2011, the dam began to impound the river. The dam's first generator is expected to be operational in 2013. The power plant will hold three 160 MW Francis turbine

Francis turbine

The Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and axial flow concepts....

-generators with an installed capacity of 480 MW.

The dam will be a 180 m (591 ft) tall variable-radius arch type with a crest length of
202 m (663 ft). The dam's crest width will be 6 m (20 ft) and the base width 28 m (92 ft) while the volume of concrete in the dam structure will be 550000 m³ (719,373 cu yd). The dam sits at the head of a 27886 km² (10,767 sq mi) catchment area

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 and will create a reservoir with a 3200000000 cubic metre capacity. The reservoir

Reservoir

A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...

's surface area will be 69.5 km² (27 sq mi) and its length 40 km (25 mi). The dam will have a main and auxiliary spillway

Spillway

A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...

. The main spillway will be controlled by two radial gates and have a maximum discharge capacity of 5763 m3/s. The auxiliary spillway will be uncontrolled and have a discharge capacity of 2467 m3/s.