Base Information

Topography

Karun 4 dam is located in south-west of Iran on Karun River uninterruptedly in upstream of Manj and Karun Rivers conjunction in 670 km of River estuary.
River bed level is 840 masl and its width in dam construction area is about 30 to 60 m. The depth of sedimentation at the project site is about 30 m.
Dam’s construction valley is V-shape and unsymmetrical with a more speedy gradient at the left side. The width of valley in +1032 m level (dam crest level) is about 350 m, therefore the ratio of the width to the height of the valley is 1 to 8 which is ideal for a double-arch concrete dam. Karun 4 dam construction location is at the border of Charmahal & Bakhtyari and Khuzestan Provinces. Its distance from Shahrekord City is 185 km and from Lordegan is 35 km. The most suitable accessible road to dam construction location is the existing road of Shahrekork-Izeh, which passes through the project site.

Geographical specifications of dam location are as follows:

	second	minute	Degree
Geographical latitude	05	24	50
Geographical longitude	53	35	31

Meteorology

Karun 4 dam’s catchment area climate in different regions is categorized between cold and semi-dried to humid and mild.
Also weather masses which are effective in Karun 4 dam catchment area are tropical weather, which is more active in winter and tropical continental climate, which is generally active in summer and also polar weather mass which influences more on the northern parts of the area.

Hydrology

Karun river’s catchment area is located in Karun 4 dam’s boundary in south-west of Iran between northern latitude of 31-20 to 32-40 and eastern longitude of 33-49 to 45-51 in Zagros Chain Mountain area and belongs to the Esfahan and Charmahal & Bakhtiary Provinces.
The mentioned catchment area is approximately mountainous, its average height is 2354 m and its highest point is about 4200 m. The area of Karun River catchment at the dam boundary is about 12813.4 km2. Zagros high chain mountains have caused suitable conditions for proper rainfall in this catchment area in a way that amount of average annual rainfall is estimated about 680 mm. Also average lake evaporation is estimated about 1811.2 mm.
River average annual discharge is 4927.4*1000000 m3 and minimum temperature at the site of dam is equal to 8°C. The maximum temperature is estimated about 4.32°C.

Flood

Karun River flood in Karun 4 dam construction site for different return periods are as follows:

Return period	Discharge (m3/s)
20 years	2715
50 years	3490
100 years	4030
200 years	4630
1000 years	6255
10000 years	8605
Maximum probable flood	10200

Water quality

Karun River water at the site of dam construction is suitable for drinking and agricultural use.

Sedimentation

50-year sediments volume of Karun River at Karun 4 dam construction site is estimated to be 220*1000000 m3.

Planning the water resources

No data is available in this regard.

Geology

From geology point of view, dam construction is located at the south western crest-line of Sefidkuh Mountain unsymmetrical anticline. The south western crest-line of this anticline is steeper than the north eastern crest-line. River at the dam construction site is flowing in direction of north-east and south-west and somehow vertically on the anticline axis.
Due to this condition, the direction of stone mass layering is along the river toward downstream. Asemary and Pabade components can be seen in dam construction location. Pabade component consists of lime stone and lime which can be observed in upstream of valley at the location of dam. Moving toward upstream, the valley becomes wide and open.
Structure and type of stone of Asemary component is divided in two sub-components of upper Asemary and lower Asemary, which are located in downstream and upstream of the river.
Upper Asemary generally includes lime-stone. Lower Asemary includes thin layers of lime-stone, which moving toward the upstream the layers’ thickness increases.

Seismicity

Karun 4 projects region has high earthquake risk.
Basically at the time of earthquake, the land energy, in form of sectional, superficial and pressure waves, is tolerated by the structure in different directions. The most severe amounts these movements in earthquake periods of less than 1 second result form sectional waves.
In seismology studies, which are carried out for Karun 4 Project, the following earthquake levels are defined for risks and hazards:

Design basis level (DBL): The design basis level of earthquake according to the definition is an earthquake which will happen during the useful lifetime of the structure.
Maximum design level (MDL): The Maximum design level of earthquake is an intense earthquake that its occurrence possibility, during useful lifetime of the structure, is low.
Maximum credible level (MCL): The maximum credible level is the highest possible earthquake.

Considering the excessive importance of dams, generally DBL and MCL earthquakes are considered as unusual and extraordinary loadings.
In Karun 4 Project maximum land’s velocity in different levels are estimated as the following:

EARTH QUAKE LEVEL	hor	ver
Design Basis Level (DBL)	0.28 g	0.18 g
Maximum Design level (MDL)	0.35 g	0.22 g
Maximum Credible level (MCL)	0.49 g	0.26 g

Dam reservoir

Karun 4 dam reservoir will have an average width of 500 m. Its normal level will be 1025 m and its minimum level will be 996 m. reservoir volume is about 2190 million m3 from which 748.7 million m3 is useful and 1097 million m3 is dead. Annual regulative water by the Karun 4 Dam reservoir is equal to 3136*1000000 m3.
Karun 4 Dam lake is formed by two branches of Armand River (with length of 40.5 km) and Bazoft River (with length of 28 km). The area of lake at the ordinary level is 29.23 km2.