In this section the project is introduced in form of following items:
- Targets
- History and background
- Location and general layout
- River specifications
- Specifications of catchment area
- Dam location
- Features
- Important effects
Targets
Generating annual hydroelectric energy of about 4500 GW/h
Controlling seasonal floods of Karun River and upstream dams
Regulating downstream water, used for agricultural purposes
Creating tourism attractions
History and background
After studying hydroelectric potentials of Catchment area of Karun River in 1960s, the issue of developing and making big reservoirs (between kilometer 490 of the river and kilometer 800) were prospered. For developing Karun River between Gotvand and Shahid Abbaspour dams, some recommendations were presented by Harza Co. in 1967, by Monenko Co. in 1975 and by Akers Co. in 1982. The first proposed dam was in downstream of Shahid Abbaspour dam and it was Godar-Lander project which its studies were carried out by Moshanir- Lahmeyer consultants. Also other dams were studied by these Consultants which their approximate locations are as follows:
First option: River kilometer of 440
Second option: River kilometer of 419
Third option: including two sub-options in river kilometer of 383 and river kilometer of 377
Finally the contract of “Gotvand Olia” engineering services was concluded between the client and Moshanir-Kaytak consultants with the target of studying the feasibility of project execution in current location. The basic studies of Moshanir-Kaytak consultants was finished in 1997 and reviewed by Lahmeyer Co. In 2003, Mahab Qods Consulting Engineers were chosen as the project consultant for completing the studies of second phase and supervision of the operation.
Excavation of diversion tunnels and Gotvand Olia power plant began in April 1997, main civil works started in 2001 and the river was diverted into tunnels, after completion of upstream cofferdam in April 2003.
- In 1997 basic studies of the project was finished by Moshanir-Kaytak J/V and reviewed by Lahmeyer Co.
- In April of the same year the water diversion operation began with excavation of the diversion tunnels.
- In 2003 karun River was diverted.
- In 2003 upstream cofferdam of the project was constructed and excavation activities of power house started.
- In autumn 2005, first power station’s draft tube installed in fourth unit.
- In January 2006, embankment operation of clay core of dam body began.
Location and general layout
Location & general layout of projectGotvand Olia hydroelectric power plant project is located in 48° and 56¢ and 10² of east and 32°, 16¢ and 8² of north. It is situated in 380 kilometers of Karun River mouth and is distanced 10 kilometers to north-east of Gotvand city in Khuzestan province.
River specifications
Karun River originates from southern Zagros Mountains in Koohrang, Armand, Khorasan, Vang and Bazoft areas and after a distance of 80 kilometers along north-east to south-east, in Khorramshahr, joins Arvanrood and pours to the Persian Gulf.
Considering the discharge, this river is the greatest river of Iran. Karun River’s average annual long-term discharge, in the area of dam construction is 453 m3/s and its annual discharge is more than 14 billion m3.
Specifications of catchmnet area
Specifications of catchmnet areaMeasurement of the catchment area at the site of dam construction is almost 32425 km2, annual discharge of Karun River at the site of dam is about 453.9 m3/s and annual average rainfall is approximately 372.7 mm.
Dam location
Dam locationAs you can see in the picture, this dam is very high and it is constructed at the final points of Karun River entering into Khuzestan plain and in its downstream no other reservoir dam will be constructed.
Features
- The highest rock-fill dam being constructed
- It has the biggest reservoir after Karkhe dam
- It is the greatest water reservoir on Karun River
- It is the last dam and power plant in downstream of Karun River
- It has a decisive role in controlling upstream power plants and dams
- It has the biggest water transfer tunnels considering the area of cross section and length
- It generates the biggest amount of hydroelectric energy in the country
- It has one of the deepest sealing walls among the world rock-fill dams
- It has a unique compound system of sealing and sealing curtain
Important Effects
Gotvand Olia dam and power plant project has an important role in employing native manpower and has been capable of direct and indirect employment of 6000 people. After complete operation of this project, the capacity of country’s electricity generation will increase considerably. This capacity can be effective in industrial and civil electricity provision. In addition to that an important resource of water supply will be available with 4.5 billion m3 capacity and it will have extraordinary effect in growth of water relevant industries, especially fishery. It also supplies water to farms and will have a vital role in creating natural tourism attractions.
Totally the most important cultural, social and economical effects of this project are as follows:
- Job-creating
- Creating tourism attractions
- Increasing the country’s hydroelectric capacity
- Growth of Hydroelectric technology and industry
- Increasing the capability of domestic consultants and contractors
- Activating the domestic manufacturers of energy-related equipments
- Promoting the international position of the country, considering the promotion of country’s electricity and water industry
- Indirect elimination of deprivation through growth of the country’s electricity resources
- Providing a big water reservoir for several purposes such as drinking, irrigating farms and fishing industry development
- Securing downstream lands against destructive floods of Karun River
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
Topography
River wall gradient is variable from 40 to 65°. The valley is generally V-shaped and is symmetrical. High altitudes of the project site reach to almost 450 meter.Meteorology
Within the project zone limit, winters are mild and short and summers are hot and long. The average annual temperature in the region is 32.5° and the minimum average annual temperature is about 20° C. Dam site is equipped with a meteorology station and the annual average rainfall is about 372.7 millimeter.Hydrology
Measurement of catchments area at the site of construction is about 32425 km2 and four hydrometer stations are installed in site of Godar, Gotvand, Shooshtar and Lali dams.Flood
Studies related to the flood are not finalized yet.But different floods and their returns period are as follows:
Water quality
Studied zone have geological and physiological diverse structure and several geological structures proportionately affect water quality. TDS in studied zone is variable between 240 milligram/liter to 740 milligram/Liter.Sedimentation
River sediment volume after 100 years is about 535 million m3. This amount is totally 15% of water volume of reservoir and has 43 m of height. Planning the water resources
According to the studies by Moshanir consultant; in case of 1000 MW power generation, power house operation is recommended to be 11h and 20m and in case of 2000 MW, power house operation is recommended to be 6 h. These figures should be reviewed carefully in future.Geology
Dam structure at bed-rock has an anticline, which its two wings slope are toward abutments. The bed-rock is from Aghajary Sazand and includes stone-sands, stone and clay layers. In both abutments Aghajary Sazand is covered with Bakhtiary Sazand conglomerates.Seismicity
Dam construction site as one of geological seismocity zone of Zagros is highly potential of earthquake. Most of huge earthquakes in this zone happen up to 1500 m of heights. Historical important earthquakes have happened in 840 in Ahwaz and in 1052 in Bagh Malek which were 6.8 Richter and the earthquake of Zagros which was 6.5 Richter. Important 
faults near the construction area are Pir Ahamd fault and... Certainly faults of Golestan, Togah, Lali and Masjed Soleiman are some of faults in 60 km distance range of the site, which can have seismocity potential.
faults near the construction area are Pir Ahamd fault and... Certainly faults of Golestan, Togah, Lali and Masjed Soleiman are some of faults in 60 km distance range of the site, which can have seismocity potential.The maximum acceleration of geo-structure for different levels is as follows:
| PGA | |||
| CBL | DBL | MDL | |
| Horizontal | 0.155 | 0.27 | 0.361 |
| Vertical | 0.101 | 0.197 | 0.275 |
Dam reservoir
Reservoir volume in PMF level (244 m) is about 5.17 billion m3. At maximum operation level that is 234 m, the volume is approximately 4.34 billion m3. Gotvand dam reservoir is located in a region with the length of 90 km within the area including Aghajary, Bakhtyari and Gachsaran Sazands.In this section the technical information of the project is presented in form of the following items:
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Dam body
Body specifications
Reservoir specifications
Diversion system
Instrumentation
Spillway
Quarries and their specifications
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Powerhouse
General specifications of powerhouse
Specifications of powerhouse equipments
Specifications of powerhouse building
Specifications of powerhouse outlet tunnels
Specifications of powerhouse waterways
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Technical specifications of post and switchyard
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Water transfer tunnels
Specifications of tunnels
Intake structures
Outlet structures
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Access roads and bridges
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Complementary operations
Body specifications
| Item | Quantity |
| Dam type | Rock-fill with clay core |
| Height from foundation | 180 m |
| Crest length | 760 m |
| Crest width | 15 m |
| Foundation width | 1075 m |
| Total volume of the body | 28.5 m |
| Sealing grouting width | 450 000 m |
| Area of sealing wall | 42 000 m2 |
| Foundation grouting width | 250 000 m |
| Grouting and access gallery length | 3750 m |
| Volume of soil and cement | 500 000 m3 |
Reservoir specifications
| Item | Quantity |
| Total volume of reservoir | 4.5 billion m3 |
| Area of reservoir | 96.5 km2 at +234 masl |
| Length of dam lake | 90 km at +234 masl |
| Width of dam lake | 1.1 km |
| Normal level | 230 masl |
Diversion system
| Item | Quantity |
| Location | Left bank of the river |
| Numbers of diversion tunnels | 2 |
| Length of diversion tunnels | Right: 1453 m Center: 1514 m Left: 1563 m |
| Tunnel diameter after lining | 9.5 m |
| Open-cut excavation volume | 2.2 million m3 |
| Underground excavation volume | 550 000 m3 |
| Cross section | U shape |
| Type of lining | Reinforced concrete |
| Tunnel excavation diameter | 11 m |
| Discharge capacity | 4200 m3/s |
| Type, height and volume of upstream cofferdam | Rock-fill with clay core, 82 m and 3.5 million m3 |
| Type, height and volume of upstream cofferdam | Rock-fill with clay core, 23.5 m and 400 000 m3 |
Instrumentation
Dam body instrumentation
| Piezometer in foundation | Hydraulic piezometer of body |
| Pore water pressure cell of foundation | |
| Pore water pressure cell of dam body |
Spillway
| Item | Quantity |
| Type of spillway | OG gated with water chute |
| Location | Left bank |
| Type of gates | Radial |
| Numbers of gates | 4 |
| OG level | +218 |
| Width of spillway | 72 m |
| Discharge capacity | 17500 m3/s |
| Diameter of gates | 15 by 17 m |
| Concrete placement volume | 700 000 m3 |
| Excavation volume | 19 million m3 |
Quarries and their specifications
| Type of materia | Location of quarry |
| Fine-graded material | Emamzade Zeid quarry with the distance of 8 km from the site |
| Drainage material | Beneheydar quarry with the distance of 11 km from the site |
| Fin-graded filter material | Kohang quarry with the distance of 57 km from the site |
| Concrete material | Beneheydar, Kohang and Andimeshk quarries |
| Rip-rap material | Manghati and Chenare quarries both with the distance of 110 km from the site |
General specifications of powerhouse
| Item | Quantity |
| Type of powerhouse | Surface |
| Capacity | 1000+1000 mw |
| Average annual generation | 4500 GWh |
| Turbine type | Francis with vertical axis |
Specifications of powerhouse equipments
| Item | Quantity |
| Numbers of turbine | 4+4 |
| Power of each turbine | 254 MW |
| Output in nominal condition | 94.4 % |
| Height of turbine design | 141 m |
| Discharge of turbine in nominal condition | 193 m3/s |
| Turbine manufacturer | Voith of Austria Azarab Arak |
| Numbers of transformers | 12+1 (spare) for 4 units 24 for 8 units |
| Nominal power of each transformer | 100 MVA |
| Nominal second voltage of transformer | 400 KV |
| Numbers and type of generators | 4+4 vertical synchronic |
| Output power of each generator | 278 MVA |
| Nominal voltage of each generator | 15.75 KV |
| Rotation speed of generator | 187.5 rotations/minute |
| Nominal current of generator | 10191 A |
| Generator manufacturer | Elin of Austria Pars Generator |
| Transformer type | OFWF |
| Basic nominal voltage | 15.75 KV |
| Cooling system | water |
Specifications of powerhouse building
General specifications of building:
(considering development plan)
| Length of the building | Width of the building | Height of the building |
| 200m | 50m | 70m |
| Item | Quantity |
| Excavation | 3 million m3 |
| Reinforcement | 22 000 tons |
| Structural and filling concrete placement | 300 000 m3 |
| Heavy metal works | 1300 ton |
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
| Type | AIS |
| Voltage level | 400 KV |
| Numbers of high voltage lines | 4+2 (development phase) |
| Input feeders | 4 |
Specifications of tunnels
Water transfer tunnels
| Item | Quantity |
| Length of water transfer tunnel | 1400 m |
| Diameter of intake transfer tunnel | 11 m |
| Type of lining | 900 m concrete 500 m steel |
| Numbers of penstocks | 2 series for first phase 4 series for second phase |
| Length of each penstock | 500 m |
| Average diameters of penstocks | 7 m |
| Numbers of surging tanks | 2 series for first phase 2 series for second phase |
Depth outlet
| Item | Quantity |
| Ceiling crane | 40 tons |
| Emergency gate (equipped with hydraulic motor) | 1 set |
| Dimension of gates | 3 by 4 m |
| Service gate (equipped with hydraulic motor) | 1 set |
| Dimension of gates | 3 by 4 m |
| Metal lining | 1 set |
| Weight of metal lining | 900 tons |
Intake structures
Hydro mechanical specifications of intake structure
| Item | Quantity |
| Numbers of intake | 4 |
| Width | 11 m |
| Height | 26 m |
| Water filling level | 154 |
| Maximum design discharge | 900 m3/s |
| Design head | 90 m |
| Gate crane | 150 tons |
| Course of gate crane | 100 m |
| Numbers of stop log gates | 1 set |
| Width of the gate | 7 m |
| Height of the gate | 12 m |
| Minimum operation level | 190 m |
| Trash rack type | Fixed |
| Course of trash rack system | 7 m |
| Numbers of wheeled gates | 4 sets |
Outlet structures
| Item | Quantity |
| Gate crane | 30 tons |
| Stop log gate | 2 sets |
| Dimension of gates | 9 by 6 m |
Access roads and bridges
1- Technical specifications of access roads
| Name of the road | Average width (m) | Length (km) |
| Substitute road of submerged area and Lali-Masjedsoleiman | 9 | 20 000 |
| Access road to chute | 9 | 9000 |
| Access road to dam crest from left bank | 11 | 5000 |
| Access road from regulating dam to construction site | 9 | 10 000 |
Technical specifications of the bridges
| Name of the bridge | Width (m) | Length (m) | Type of structure |
| Lali big bridge | 14.5 | 480 | |
| Gotvand city bridge | 11.5 | 260 | |
| Permanent bridge of the site | 13 | 150 |
2- Technical specifications of access tunnels
| Name of the tunnel | Width (m) | Length (m) | Height (m) |
| Emamzade Zeid tunnel | 10 | 700 | 7 |
| Access tunnel to spillway excavations | 10 | 360 | 7 |
| Access tunnel to water transfer tunnels | 10 | 970 | 7 |
| Access tunnels to grouting galleries | 6 | 4000 | 5 |
Complementary operations
Lateral buildings:
Construction activities of the client’s office and the residential building of equipment contractor are finished and they are handed over temporarily. Sport complex, supervisors and client’s residential building and VIP is in finishing stage. Parallel to that the civil works of the main site and the structure of feasibility building are about to be finished. In the mean time sewerage system of Emamzade Zeid complex is being installed and all of the buildings of equipment contractors are handed over to Engineering Affairs Dept.