In this section the project basic information is presented in form of following
Seimare River water system has a length of more than 450 km and a catchment area of 27886 km2 which forms more than 75% of total area of Karkheh catchment area. Catchment area of Seimare River is located in geographical coordinates of 46° and 7¢ to 49° and 10¢ of eastern latitude and 33° and 1¢ to 35° and 0¢ of northern longitude.
|Catchment area gradient
|Catchment area average height
||River average gradient
||Main River length
Due to Seimare catchment area location in Zagros Chain Mountains, climate of this area is different in different parts. In North West the climate is cold and semi humid, in North East (Gamasyab River Catchment area) the climate is cold and semi-arid, in middle part it has a cold and semi-dried climate which by going toward southern parts the climate changes to semi-dry. In Seimare dam catchment area, average rainfall in a common period of 46 years (1958-1959 to 2003-2004) is equal to 442.7 mm. In the location of dam’s lake, annual temperature is 20.2° C, annual proportional humidity is 49%, the average of annual under-zero temperature days is about 26 days, average level change in dam surface water is 1883 mm and maximum wind speed within 25 years return period is about 24.8 m/s. In area of Seimare River Catchment area and its surroundings there are 162 meteorology stations that 109 of them belong to the Ministry of Energy and 53 of them belong to Meteorology Organization. Functioning quality and duration of statistical period of these stations are not similar. Some of them are established in recent years and some of them have been closed down. General conditions of the most of the existing stations are good to some extent.
In Seimare Catchment area there are 33 hydrometric stations that some of them are closed and some are established in recent years. For hydrology studies, stations of “Ghoorbaghestan”, “Pol Chehr”, “Hedseylan”, “Sazbon” and “Nazar Abad” are the basis of calculations. Physiographical conditions of Seimare Catchment area in the place of Seimare dam has an area of 27886 m2 and average height of 1644 m, dominate height is 1700 m, river average gradient is 1/3 in 1000 and River length is 417 Km.
River discharge in Seimare dam location according to the “Nazar Abad” station from “Nazar Abad” to “Sazbon” is equal to 102.84 m3/s. Maximum amount of discharge is in March (280.57 m3/s) and the minimum amount is in August (21.44 m3/s). The river inlet water volume is 3.235 billion m3.
According to the existing information from occurred floods, most of the floods happen in spring and fall. The biggest flood with discharge of 3629 m3/s happened in 1973-1974 in Nazar Abad station. Floods with time periods of 2, 5, 10, 25, 50, 100, 50000, 10000 years are orderly equal to 625, 1143, 1597, 2251, 2781, 3335, 5334, 7534 m3/s.
According to the regional stations data, especially Sazbon and Nazar Abad stations, water quality for agricultural use is in C3S1 and C2S1 classes and is suitable for drinking, but in crisis time it is unsuitable to unacceptable.
50 years sediments volume without “Kooran Bozan” and “Sazbon” dams is 6112 million m3.
50 years sediments volume considerting “Kooran Bozan” and “Sazbon” dams is 95.3 million m3.
|Planning the water resources|
Normal level: 1756
Minimum operation level: 1721
Reservoir volume at normal level: 228.3
Reservoir volume at minimum operation level: 103.7
Installation capacity: 450 megawatt
Units: 2 units
Total energy: 986 Gwh/year
Average inlet discharge: 975.3 million m3
Spilling amount: 32.1 million m3/year
Evaporation amount: 0.9 million m3/Year
Design head: 434 m
Minimum head: 414 m
Maximum head: 449m
Design discharge of each unit: 58.8 m3/s
Studied region is located in south-western folded Zagros zone. This region has high chain mountains with direction of North West to South East. Sequences of stone anticlines and synclines can be found a lot in this area.
Stratigraphy stone sequences of Seimare region belongs to “Karnameh” or “pleostivason”, “Sadook”, “Ilam”, “Paydeh”, “Asemary” and “Gachsaran” Sazands. Tectonically, this structure is located in folded belt of Zagros on the southern tail of “Ravandi” anticline and on its northern part.
Dam and its lateral structures are constructed on Asemary Sazand. The surface elements of dam construction location can be divided into categories of present age, lake sediments, and old bed-alluviums. Maximum thickness of surface in river-bed is about 50 m.
Layering gradient in dam location is about 30° which increases up to 50° in upstream.
Totally about 13 faults are explored in dam construction area that are functioning normally and are parallel to the anticline axis.
Average penetration of river-bed is not much and average stone quality index is good.
Seimare dam is located in seismic area of Zagros with small to medium earthquakes. One of the seismic sources is hidden fault of “Kabir Kooh” that its big earthquakes have a return period of 7000 years. Seimare big earthquakes have occurred in 2 phases on this anticline 14000 years and 7000 years ago. The latest earthquake event on these seismic sources was the earthquake of 872 A.D in Madakto which was 6.8 Richter, 10 km away from Seimare dam structure.
|Reservoir total capacity
3216 million m3
|Water minimum level
|Reservoir useful capacity
||941 million m
||Water maximum level
|Water normal level
Bedrock is calcareous stone of “Sazan Asemary Shahbazan” which is divided in to 3 parts:
Upper Asemary unit with 50 m thickness, which the bedrock of power house construction location is this type.
Middle Asemary unit with 220 meter thickness, which is the main bedrock of foundation and tunnels.
Under Asemary unit which is weak.