• Introducing the plan
  • Basic Information
  • Technical Information

In this section the project is introduced in form of following items:

  • Targets
  • History and background
  • Location and general layout
  • River specifications
  • Specifications of catchmnet area
  • Dam location
  • Features
  • Side effects








  • Generating hydroelectric energyTargets
  • Preventing Bakhtyari River sediments from entering into dam reservoir and therefore increasing life-time of Dez dam and power plant
  • Controlling floods, preventing its annual destruction and improving the conditions
  • Safety measures in downstream of dam






History and background

History & background of the projectThe preliminary studies about Bakhtiari project started in March 1996 by Mahab Qods Consulting Engineers and continued for about 33 months. Related reports of the first phase of the project were handed over to the client (IWPC) in March 2000.
After electing the project manager in 2004 and transferring the management of the project from IWPC deputy department, negotiations related to electing the consultant of the second phase of the project continued and finally in May of 2005, IWPC handed over the consulting services of the project (including review and completion of the first phase studies, the second phase studies and preparing tender documents) to the following group of consultants:

  • Moshanir Consulting Engineers
  • Dezab Consulting Engineers
  • Econo-Electrowatt (Swiss)/ Boyri joint-venture
  • Stucky Pars Consulting Engineers
  • with common and individual responsibilities. 

Location and general layout

Construction location of Bakhtiari dam and power house is in downstream of the Bakhtiari River in Lorestan Province, in south-western parts of Iran and in south-western domain of Zagros Mountains; in a zone with eastern longitude of 48°, 46' and 50" and northern latitude of 32°, 57' and 41"; which is situated in north-west of Tangpanj station on railway rout of Tehran-Ahwaz on Bakhtiari river.
Construction location of Bakhtyari dam has 50 km direct distance from upstream of Dez dam and 5 km distance from upstream the Sezar and Bakhtiari rivers’ cross section.

River specifications

Bakhtiari River is one of the main branches of Dez River which originates from the southern heights of Oshtorankooh Mountain and in the vicinity of Tangpanj station joins to Sezar River and forms Dez River.

Specifications of catchmnet area

Measurement of the catchment area at the site of the dam construction is about 6288 km2 and the average of catchment area height from sea level is 2212 m. Average annual discharge of Bakhtyari River at dam site is about 144.6 m3/s (according to testing period of 60 years) and average annual rainfall in this area is about 1117 mm. average slope of Bakhtiari River in its route is about 35 degrees.

Dam location

Dam locationAs it is shown in the image of project location; in the area of Karun and Bakhtiari catchment area, Bakhtiari dam will be constructed in upstream of (Dez) dam with a distance of 50 km to it.







  • The highest double arc dam of the world with the height of 325 m
  • The biggest artificial reservoir of the country after Karkheh reservoir, with the capacity of 5.2 billion m3 at normal level
  • No need to displace inhabitants of the reservoir area (due to the fact that this area is difficult to pass) after construction and water filling not many agricultural lands and no permanent village will go under water
  • Power-plant capacity at 20% functional coefficient is
  • 1500 W and its annual power generation is about
  • 3000 GW/h
  • Remarkable role of water supply and water regulation of the dam due to huge capacity of its reservoir
  • Big economical indices of this project in comparison with economical indices of other projects, including hydro electric projects
  • Controlling seasonal floods and improving security conditions in down stream of dam
  • Preventing sediments of Bakhtiari river to enter dam reservoir and as a result increasing the profitable life-time of Dez dam and power-plant
  • Remarkable increasing of water supply capacity in catchment area for better management of water resources and increasing volume of regulated water and as a result increasing the area of agricultural lands in downstream
  • Possibility of generating the optimum energy in daily and annual peak periods of energy consumption

Side Effects

Bakhtiari dam and power-plant project, during implementation, will have important effects on regional job creation by employing regional man-power. Improvement of social, economical and cultural conditions in the region, providing opportunities for development and investment, improving the welfare level of the regional inhabitants, promoting the educational and health level and increasing the annual income, better use of tourism attractions of the region, increasing the share of the region in development of the country, improvement of the land transportation through access roads and increasing the added value of services in the region will be some of economical, cultural and social effects of this national project.

In this section the project basic information is presented in form of following items:

  • Topography
  • Meteorology
  • Hydrology
  • Flood
  • Water quality
  • Sedimentation
  • Planning the water resources
  • Geology
  • Seismicity
  • Dam reservoir






River length is more than 300 km and Bakhtiari dam has a catchment area of 6388 km2.

Item Quantity
Catchment area 6388 km2
Average height of catchment area 2212m
Catchment area slope 35%
Average slope of the river  5.65%
Length of main river 300 km



Item Quantity
Average annual rainfall in catchment area 1117 mm
Average evaporation of reservoir 1780 mm
Average annual temperature of dam construction site 21.2 °C
Probable maximum rainfall (PMP) 144 mm

Within the catchment area there are 5 meteorology stations, which although they do not have similar outputs, but generally their situation are estimated to be desirable.


The studied regional stations include Taleh Zang Dez, Tangpanj Sezar, Tangpanj Bakhtiari, Sepid Dasht Sezar, Zaz, Zard Fahrah, Ghelyan and Kazem Abad Kakolestan.

Item Quantity
Catchment area 6388 km2
Concentration time 35 h
Average slope of the river 35%
Average outflow of water in Tangpanj station 144.6 m3



According to the existing data achieved from floods, most of the floods have taken place in spring and fall. The biggest observed flood in Bakhtiari River had a discharge of 4988 m3/s and occurred in Azar of 1994. Estimated discharge of floods with several return periods is presented in the following table:

Return Period 2 25 100 1000 10000
Peak discharge (m3/s) 2489  3910  5043  6857  8641


Water quality

Quality of Bakhtiari River water with ER and TDS are orderly 1090 maximum and 376 for drinking and agricultural use.




Annual sediments volume of the area is estimated about 9 million m3.





Planning the water resources

Item Quantity Unit
Normal figures 830 masl
Minimum figures 785 masl
Reservoir minimum volume 2722 mmm
Reservoir volume at normal figures 5200  mmm
Reservoir profitable volume 2122  mmm
Annual inlet volume 4307 mmm
Water regulation volume 3688 mmm
Safety functional coefficient 21 %
Power house installation capacity  1500 Mw
Primarily annual energy 2368 GWH
Secondary annual energy 617 GWH
Output 92 %



The project location is wrinkled at north-west of Zagros sedimentary catchment area and is situated in Dezful low lands. This structure is situated mostly on Silica-lime of serok Sazand. Some of the important geological structures of the area are Gir Yoveh & Sia Klooh anticline, F1, F2 and F3 faults and kink bands. The penetration amount in left side is somehow high. Seismic topography tests results shows average velocity of 3200 to 2700 m/s in abutment and 500 m/s at foundation, which are not due to stone mass quality. Underground and galleries explorations and grouting tests are being carried out. 
The soil mechanic tests for determining the module of shape alternation and other physical specifications of stone mass are also being carried out.


Bakhtiari dam seismocity parameters are studied regarding seismography data of the region and general behavior of Zagros. With use of Deterministic method and Probabilistic method, the maximum amount of land horizontal velocity for
50-year return period (CE) is 0.15g, 145-year return period (OBE) is 0.23 g, 475-year return period (DBE) is 0.32 g and for 2000-year return period (MDE) is 0.45g. Maximum acceptable earthquake (MDE) for F3 fault is equal to 0.55 g which is equal to the vertical velocity of 0.429.

Dam reservoir

Item Quantity
Total volume of reservoir 5200 million m3
Profitable volume of reservoir 3027 million m3
Water normal level 830 masl
Water minimum level 782.2 masl
Water maximum level 840 masl

Dam construction area is generally located on silica-lime Sazand of the Serok and according to the layers thickness and silica compounds, is divided into seven sub-units of Sv1 to Sv7. Some of the important geological structures are anticline of Giriveh and Siahkooh, F1-F3 trust, younger fault of F2, kink bands, forked clines and four joint systems at construction site. Slope and direction of layering slope, generally at downstream of anticline axis is N215/75 and in its upstream is N035/50. The issue of studying slope stability in current situation, without considering the artificial off-take of materials in axis area and other structures, does not show any difficulty and the abutments are stable in case of earthquake.

In this section the technical information of the project is presented in form of the following items:

1-Dam body

  • Body specifications
  • Reservoir specifications
  • Diversion system
  • Instrumentation
  • Spillway
  • Quarries and their specifications


  • General specifications of powerhouse
  • Specifications of powerhouse equipments
  • Specifications of powerhouse building
  • Specifications of powerhouse outlet tunnels
  • Specifications of powerhouse waterways

3-Technical specifications of post and switchyard

4-Water transfer tunnels

  • Specifications of tunnels
  • Intake structures
  • Outlet structures

5-Access roads and bridges
6-Complementary operations

Body specifications

Item Quantity
Dam type Double arc concrete
Height from foundation 315 m
Crest length 434 m
Crest width 10 m
Foundation width 50 m
Total concrete placement of the body 3.1 million m3
Specifications of sealing system
Sealing method Grouting curtain
Total length of grouting 58 km

Reservoir specifications

Item Quantity
Total volume of reservoir 5200 million m3
Area of reservoir 58.7 km
Length of dam lake 59 km
Width of dam lake 1000 m
Normal level 830
Profitable volume of reservoir 3027 million m3

Diversion system

First tunnel
Location Left abutment
Length of diversion tunnels 1151 m
Cross section Circular
Tunnel diameter after lining 12 m
Discharge capacity 2090 m3/s
Type of lining concrete
Second tunnel
Location Left abutment
Length of diversion tunnels 1180 m
Cross section U shape
Tunnel diameter after lining 13 m
Discharge capacity 1680 m3/s
Type of lining concrete
Type an height of upstream cofferdam RCC 51 m
Type an height of downstream cofferdam RCC 25 m


No date exists in this regard.






Item Quantity
Type of spillway Gated with tunnel
Location Right abutment
Type of gates Radial
Numbers of gates 2
Diameter of tunnel 11 m
Discharge capacity 5830 m3/s
Dimension of gates 17.7 by 11 m

Item Quantity
Type of spillway Orifice
Location Dam body
Type of gates Radial
Numbers of gates 2
Diameter of tunnel 11 m
Discharge capacity 1510 m3/s
Dimension of gates 6.5 by 3.5 m

Quarries and their specifications

Totally around 3 500 000 m3 of sand material is needed for the project. In order to find the suitable quarry, it became evident that within the radius of 40 km around the dam location, no river quarry exists. Therefore three areas were considered for this purpose.
A- Excavation materials within the area of dam body
     and power house:
The volume of excavation materials of dam foundation, spillways, power house will reach 2 700 000 m3, from which only 60 percent (equal to 1 600 000 m3) will be used for sand material.
B- QU1 and QU2 quarries:
These quarries are located within 2 km range of downstream of dam axis and the volume of their material reaches 3.5 million m3.
C- Upstream quarries:
This quarry is located in the area of fourth unit of Saruk Sazand (upstream of batching plant location). It has a good volume of 4 million m3 suitable material.
The results of short term chemical and physical tests is generally satisfactory and the reactions of available material are alkaline-solicit and alkaline-carbonate. Therefore long term tests are being carried out in this regard.

General specifications of powerhouse

Item  Quantity
Type of powerhouse Underground
Location Left abutment
Capacity 1500 mw
Average annual generation 3000 million kw/h
Turbine type Francis with vertical axis
Operation level Minimum critical 770
Normal 791
Maximum 830

Specifications of powerhouse equipments

Item Quantity
Numbers of turbine (main phase)  6 units
Numbers of turbine (development phase) Being designed
Power of each turbine 250 MW
Maximum output 92 %
Height of turbine design 250 m
Design discharge of each unit 104.5 m3/s
Numbers of generators (main phase) 6 units
Numbers of generators (development phase) Being designed
Type of generators Being designed
Output power of each generator 250 mva
Rotation speed of generator 272.7 rotations per minute

Specifications of powerhouse building

Powerhouse cavern
Length Width Height
161m 24m 64m
Total volume of excavation 180 000 m3
Total volume of concrete placement Being designed

Specifications of powerhouse outlet tunnels

In this regard no data exists.




Specifications of powerhouse waterways

In this regard no data exists.






Technical specifications of post and switchyard

Specifications of switchyard and 400 kv transfer lines
Post voltage 400 KV
Arrangement type of post 1.5 key
Numbers of  B Being designed
Intake numbers Being designed
Outlet numbers Being designed
Area of post land 50 000 m2
Specifications of 400 post
Numbers of transformers  Being designed
Numbers of feeders of transformers Being designed
Power of each transformer Being designed
Numbers of outlet feeders Being designed
Voltage of each outlet feeder Being designed

Specifications of tunnels

Main Phase
Length of water transfer tunnel 504 m
Diameter of intake transfer tunnel 8 m
Diameter of outlet transfer tunnel 9.5 m
Type of lining Concrete
Numbers of intake penstocks 6
Length of each penstock 51 m
Average diameters of penstocks 6.5 m

Development phase is being designed.

Intake structures

Item Quantity
Numbers of intake 3
Maximum design discharge 104.5 m3/s
Design head 228.5-289.3 m
Numbers of  valves 2 series of 4
Type  Stop-log
Valve of intake structure Radial
Width of valve Being designed
Height of valve Being designed

 Outlet structures

Item Quantity
Numbers of intake 6
Maximum design discharge Being designed
Design head Being designed
Numbers of  valves Being designed
Type  Being designed
Valve of intake structure Being designed
Width of valve Being designed
Height of valve Being designed

Access roads and bridges

A- Internal access roads

1-Technical specifications of internal access roads

Name of the road Average width (m) Length (km)
Downstream road 9 8
Access road to crest and site stabilization area  9 10

2- Technical specifications of internal bridges

Name of the bridge Width (m) Length (m) Type of structure
Sezar 3 bridge 9 190 Metal sheet shaft with concrete
Dez bridge 9 150 Metal sheet shaft with concrete
Doab bridge 9 40 Metal sheet shaft with concrete
Sezar 2 bridge  7 100 Metal sheet shaft with concrete
The bridge adjacent to diversion tunnel 6 90 Roof-truss
Entrance bridge to GL6 tunnel 6 75 Roof-truss

B- External access roads

In order to have road access to construction location of Bakhtiari dam, Board of Managers of IWPC approved to construct an access road from Khorramabad city to Tangpanj station. The distance between Khorramabad and Tangpanj station is 112 km.
The width of the said road is 7 m and other details are being designed. This road includes the following components:
1- Khorramabad- Cheshmak with the length of 32 km, including the existing asphalt road
2- Cheshmak- Emamzade Seyed Ali with the length of 25 km, including the existing road which need asphalt lining
3- Emamzadeh Seyed Ali- Tanghaft with the length of 35 km, 20 km of which is rehabilitation of the existing road and the rest should be constructed
4- Tanghaft- Tangpanj with the length of 20 km, that should be constructed

Complementary operations

In this regard no data exists.

    Post Address

  • Post Address : No.3.BIDAR st. AFRICA junction, MODDARES Exp,Way TEHRAN - Post Code: 19649-13581, IRAN
  • Phone : +98 (21) 27823113
  • Fax : +98 (21) 26213732
  • e-Mail :