Seimare

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
• Important effects

Targets

• Constructing 3 units of 160 megawatt with annual generation of 850 million kw/h
• Constructing a double arc concrete dam with 180 m height, 202 m length and a reservoir with the volume of 3200 million m3

History and background

Ilam is one of provinces with thousands of years of history and is considered as cradle of civilization in ancient Iran. Existing petrographies and historical remaining from Madian government on one hand and current resistance of this province’s people against foreign aggression on the other hand, has made the government’s authorities pay special attention to this province. In this regard infrastructure projects are considered as a necessary factor.

Lorestan province is a beautiful place with pleasant climate in high mountains. This province is located in the middle Zagros Chain Mountains. Ecological situation of the province has made this place suitable for economical development. Several historical places with outstanding cultural backgrounds together with many tourism attractions are among exceptional features of Lorestan province.

• Karkhe catchment area civil project which its studies were carried out in 1975 by Electro Consult Co.
• Karkheh catchment area civil project which its studies were carried out in 1978 by “Omran and Manabe” Co.
• Studies related to recognition phase of Karkheh origins which in 1990 were carried out with cooperation of “Mahab Qods’ and “Electro Consult” Corporations. In this regard some construction locations were introduced including “Tang Sazbon”, “Tange Kafe Nil” or “Kafan Dahla” and “Tang Pa Alam” for basic studies.
• Studies of Seimare dam and power plant which in 1993 was handed over to “Mahab Qods and Electro Consult” Corporations. Since 1995 with resignation of Electro Consult Corporation, Mahab Qods has continued the works.
• In 1997 the results of “ELC” experts’ studies were presented under the title of Technical Reports of Reformation and Ratification of First Phase of Seimare and Sazbon Projects.
• In 1997 excavation and lining of diversion tunnels started by Sab Co. and ended in 2002. In the course of temporarily handing over of diversion tunnels in 2001, in a plane crash some of the colleagues lost their lives.
• Excavation of a part of water transfer tunnel, shaft and shock absorber shaft began in 2000 by “Zigoratt” Co. and ended in 2005.
• In 2002 construction of upstream and downstream cofferdam and dam body began and was finished in 2003 coinciding with diversion of Seimare River. In 2006 excavation of dam foundation also ended.
• In 2003, excavation of some parts of power plant construction location and access road to power plant began by Motabar Co. and ended in 2006.
• In 2005 the contract of power house building and equipments was concluded with “Farab, Farab International, Tablieh and Parhoon” group of companies.
• In 2006 the contract of remaining water transfer tunnel was concluded with “Payab Kosar” Co.
• In 2006 concrete placement of dam body began with attendance of Ilam governor, region representative in the parliament and general manager of IWPC.
• In 2007 with opening of Penstock no.2 the intake and outlet of tunnel was practically opened.

Location and general layout

River specifications

River specificationsSeimare and Kashkan Rivers are main branches of Karkheh River. Seimare River with length of 417 km and gradient of 0.3% is formed by joining Ghareh Soo and Gamasyab Rivers and its most important minor branches are Chardavol and Shiravan Rivers.

Specifications of catchmnet area

Specifications of catchmnet area Catchment area level in dam structure location is 27886 km2. Annual average discharge is 109.5 m3/s, which is calculated in the statistical period of 36 years. 

Dam location

Dam location According to the following picture, Seimare dam is located between Sazbon dam in upstream and Paalam dam in downstream of the river.

Features

Important effects

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

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	27886.2 km2	Catchment area gradient	5.5%
Catchment area average height	1646.2m	River average gradient	3.1%
Dominate height	1960m	Main River length	417 kilometer

 

Meteorology

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.

Hydrology

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.

Flood

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.

 

 

Water quality

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.

 

 

 

Sedimentation

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

Geology

Regional geology:

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.

Seismicity

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.

 

 

 

Dam reservoir

Reservoir total capacity	3216 million m3	Water minimum level	705
Reservoir useful capacity	941 million m	Water maximum level	731
Water normal level	720	Sediment level	622

 

Bedrock is calcareous stone of “Sazan Asemary Shahbazan” which is divided in to 3 parts:

1. Upper Asemary unit with 50 m thickness, which the bedrock of power house construction location is this type.
2. Middle Asemary unit with 220 meter thickness, which is the main bedrock of foundation and tunnels.
3. Under Asemary unit which is weak.

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

• Dam body

1. Body specifications
2. Reservoir specifications
3. Diversion system
4. Instrumentation
5. Spillway
6. Quarries and their specifications

• Powerhouse

1. General specifications of powerhouse
2. Specifications of powerhouse equipments
3. Specifications of powerhouse building
4. Specifications of powerhouse outlet tunnels
5. Specifications of powerhouse waterways

• Technical specifications of post and switchyard
• Water transfer tunnels

1. Specifications of tunnels
2. Intake structures
3. Outlet structures

• Access roads and bridges
• Complementary operations

Body specifications

Reservoir specifications

Diversion system

 Instrumentation

Totally 632 instrumentation device is used including direct and upside- down pendulums,  joint meter, three dimension joint meter, thermometer, inclinometer, extensometer, piezometer and 360 thermocouple for measuring temperature during construction period.

Spillway

Quarries and their specifications

In this regard no data exists.

General specifications of powerhouse 

Specifications of powerhouse equipments

Specifications of powerhouse building

General specifications of building:

 Specifications of powerhouse outlet tunnels

Specifications of powerhouse waterways

Technical specifications of post and switchyard

No data exists in this regard.

Specifications of tunnels

Intake structures

No data exists in this regard.

Outlet structures

No data exists in this regard.

Access roads and bridges

Complementary operations