Tarbela Dam (Dam)

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Article Upload Date: Tue 06 Jun 2017
2017-06-06 15:41:38Tarbela Dam
Tarbela Dam, giant rock-fill dam on the Indus River, Pakistan. Built between 1968 and 1976, it has a volume of 138,600,000 cubic yards (106,000,000 cubic m). With a reservoir capacity of 11,098,000 acre-feet (13,690,000,000 cubic m), the dam is 469 feet (143 m) high and 8,997 feet (2,743 m) wide at its crest. Tarbela Dam is one of two main structures (the other is Mangla Dam on the Jhelum River) in the Indus Basin project, which resulted from the Indus Waters Agreement between India and Pakistan. Together with their subsidiary dams, Tarbela and Mangla were built to control seasonal fluctuations on the Indus River.[1] Tarbela Dam, giant rock-fill dam -   the Indus River
  • Information
  • Location:

    Tarbela, Khyber Pakhtunkhwa, Pakistan

  • Nickname:

    Earth fill dam

  • Type:

    Embankment dam

  • Local Language Name:

    تربیلا بند

  • Coordinates :

    34°05′23″N 72°41′54″E

  • Power Station Unit:

    14

  • UNITS 1-10:

    175 MW EACH (Total 1750 MW)

  • UNITS 11-14:

    432 MW EACH (Total 1728 MW)

  • TUNNEL-1 :

    4 UNITS OF 175 MW EACH (COMPLETED 1977)

  • TUNNEL-2:

    6 UNITS OF 175 MW EACH (COMPLETED 1985)

  • TUNNEL-3:

    4 UNITS OF 432 MW EACH (COMPLETED 1993)

  • Service Spillway:

    No of Gates, 7 (50 feet wide x 61 feet high)

  • Auxiliary Spillway:

    No of Gates, 9 (50 feet wide x 61 feet high)

  • Details
  • Construction began :

    1968

  • Opening date :

    1976

  • Construction cost :

    USD 1.497 billion

  • Impounds :

    Indus River

  • Height :

    143.26 metres (470 ft) from river level

  • Length :

    2,743.2 metres (9,000 ft)

  • Creates:

    Tarbela reservoir

  • Total capacity :

    13.69 cubic kilometres (3.28 cu mi)

  • Catchment area :

    168,000 km2 (65,000 sq mi)

  • Surface area :

    250 km2 (97 sq mi)

  • Turbines :

    10 × 175 MW 4 × 432 MW

  • Installed capacity :

    3,478 MW 6,298 MW (max)

Detail

The project is at a narrow spot in the Indus River valley
The project is at a narrow spot in the Indus River valley

Location

The main dam wall, built of earth and rock fill
The main dam wall, built of earth and rock fill
Tarbela Reservoir is 80.5 kilometres (50.0 mi) long
Tarbela Reservoir is 80.5 kilometres (50.0 mi) long
Tarbela Dam was constructed as part of the Indus Basin Project
Tarbela Dam was constructed as part of the Indus Basin Project
The dam is 485 feet (148 m) high above the riverbed
The dam is 485 feet (148 m) high above the riverbed
Tarbela Dam is one of the world’s largest earth and rock filled Dam and greatest water resources development project which was completed in 1976 as a component of Indus Basin Project. The Dam is located on the river Indus known as the “Abbasin” or the father of the river at a distance of 130 KM (50 Miles) to the North West of Islamabad, in Distt Sawabi KPK.Emerging from the land of glaciers on the northern slopes of Kailash ranges, some 17,000 feet (5182 meters) above sea level, the river Indus has its source near the Lake Mansrowar in the Himalyan catchment area. It flows over 1800 miles (2900 k. meters) before it outfalls into the Arabian sea draining an area of about 372,000 square miles (964,261 sq.kms).In stage-II, the main embankment dam and the upstream blanket were constructed across the main valley of the river Indus while water remained diverted through the diversion channel. By the end of stage-II, tunnels had been built for diversion purposes. The Stage-II construction took 3 years to . Under stage-III, the work was carried out on the closure of diversion channel and construction of the dam in that portion while the river was made to flow through diversion tunnels. The remaining portion of upstream blanket and the main dam at higher levels was also completed as part of stage-III works.[3] embankment dam upstream blanket - constructed  Construction The construction of Tarbela Dam was carried out in three stages to meet the diversion requirements of the river.
  • In stage-I, the river Indus was allowed to flow in its natural channel while work was continued on right bank where a 1500 feet (457 meters) long and 694 feet (212 meters) wide diversion channel was excavated and a 105 feet (32 meters) high buttress dam was constructed with its top elevation at 1,187 feet (362 meters). Construction under stage-I lasted 2.5 years.
  • In stage-II, the main embankment dam and the upstream blanket were constructed across the main valley of the river Indus while water remained diverted through the diversion channel. By the end of stage-II, tunnels had been built for diversion purposes. The Stage-II construction took 3 years to complete.
  • In stage-III, the work was carried out on the closure of diversion channel and construction of the dam in that portion while the river was made to flow through diversion tunnels. The remaining portion of upstream blanket and the main dam at higher levels was also completed as part of stage-III works.
Tunnels The four each of half mile long, tunnels through the right (rock) abutment initially served for the diversion of water during the final phases of construction of the Project. Now, they are being used for Power generation (tunnels 1, 2, 3 and eventually 4). The discharge capacity of each irrigation tunnel at higher reservoir elevations is approximately 90,000 cusecs (2,549 cumecs). The discharge pass through energy dissipater structures and the water returns to the river. A fifth tunnel on the left bank designed to augment irrigation releases upto 80,000 cusecs (2,265 cumecs) at high reservoir level, has also been added to the project.[4] The four each  half mile  tunnels - through the right
  • Tunnels at Right Bank
  1. Number 4
  2. Length 2400 feet each (732 M)
  3. Diameter (u/s gate shafts) 45 feet (13.72 M)
  4. Diameter (d/s gate shafts) 36 feet (10.97 M)
  5. Discharge Capacity 90,000 cusecs (2,549 cumecs)
  • Tunnels at Left Bank
  1. Length 2760 feet (841 M)
  2. Diameter (u/s gate shafts) 43.5 feet (13.26 M)
  3. Diameter (d/s gate shafts) 36 feet (10.97 M)
  4. Discharge Capacity 80,000 cusecs (2,265 (approximately) cumecs)
Project Benefits In addition to fulfilling primary purpose of the dam i.e. supply water for irrigation, Tarbela Power Station has generated 438.978 Billion KWh of cheap Hydel energy since commission. A record annual generation of 16.463 Billion KWh was recorded during 1998-99. Annual generation during 2013-14 was 15.181 Billion KWh while the station shared peak load of 3605 MW was recorded during the year.[5] Tarbela Power Station generated - 438.978 Billion

Spill Ways

Service Spillway
  • No of Gates 7 (50 feet wide x 61 feet high)
  • Discharge 650,000 cuses
Auxiliary Spillway
  • No of Gates 9 (50 feet wide x 61 feet high)
  • Discharge 850,000 cuses

E M Equipment of Tarbela

Its primary use is electricity generation
Its primary use is electricity generation
Turbine            
Units(1~4)(5~8)(9~10)(11~14)
Turbines MakeHitachi JapanDEW CanadaDBS CanadaDBS/SEW Canada
TypeVertical FrancesVertical FrancesVertical FrancesVertical Frances
Rated Output (BHP)275,000 / 239,000275,000 / 239,000275,000 / 239,000596,000
DesignedHead (FT)270333333270
Rated Head (FT)378378378385
Speed (RPM)136.4136.4136.490.9
Rated Discharge for one unit (CFS)67006700670015000
Generators
Units(1~4)(5~8)(9~10)(11~14)
Generators MakeHitachi JapanCGE CanadaHitachi JapanSiemens Germany
TypeSemi Umbrella
Rated Capacity (MW)175175175432
Power Factor0.850.950.950.90
Rated Voltage13.813.813.818
Speed (RPM)136.4136.4136.490.9
Overload Capacity115%115%115%-
Power Transformer
Units(1~4)(5~8)(9~10)(11~14)
Capability (MVA/Phase)797171160
Voltage Ration (KV)13.2 /22013.2 /50013.2 /50025.0 /500
MakeJeumont Schneider FranceASEA Canada/ Hitachi Jap/ TBEA ChinaHitachi JapanAnsaldo Italy

The Barrage

Tarbela Dam
Tarbela Dam
The Barrage located 7 km downstream of Tarbela Dam, provides a pond which re-regulates the daily discharge from Tarbela by diverting the flow into the Power Channel. The principal features include 20 No. standard bays, 8 No. under sluices and 8 No. head regulator bays in addition to rim embankments, fuse plug and dividing island. The Barrage can pass the design flood of 18,700 cumecs, equivalent to the flood of record, through the standard bays and under sluices at the normal pond level of El. 340 m. The fuse plug has been provided to pass the extreme flood up to the capacity of Tarbela’s spillway and tunnels equaling 46,200 cumecs.{:ref:{ Tarbela Dam, provides a pond which - re-regulates }}


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