Survey of Existing Dams

1
Survey of Existing Dams

• 1.096 Environmental Engineering Clinic
• Week 2 - February 13, 2004
• Teresa Yamana

2
Objective

• To gain insight into our assessment of the Merowe
  Dam in the areas of
• Sedimentation
• Small Scale Impacts
• Archeology
• Public Health
• Resettlement

3
Three Gorges Dam, China - Yangtze River
www.cbc.ca/news/features/threegorges_quickfacts.ht
ml
4
Dam Overview

• Purpose
• Flood prevention
• Power generation
• Cost 24.7 billion
• Expected Completion 2009

• Height 175 m
• Reservoir
• Area 1080 km2
• Volume 39.3 bcm
• Power Capacity 18,200MW

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Sedimentation in Reservoir

• 40 year sedimentation observation data
• Store clean water during dry season, sluice muddy
  water in flood season
• Scouring and silting to reach balance
• Initial sediment discharge rate 30-40
• Storage remaining after 100 years
• Flood storage 86
• Regulated storage 92

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Downstream Effect of Sedimentation

• Erosion of riverbed, leading to decrease in water
  level between 0.5 - 8.0m
• Requires minimum 5000 m3/s discharge at Yichang
  shiplock
• Caving banks
• Shallow bendways impede local navigation
• Mitigate damage of flood and waterlogging in
  Dongting Lake area

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Small Scale Impacts

• Archeology
• 1300 Archeological sites to be submerged
• Cultural relics from various dynasties
• 200 ancient tombs
• International effort to excavate

• Public Health
• Unlikely increase in schistosomiasis
• Likely increase in malaria, other local water
  related diseases
• Resettlement
• 844,124 residents
• Relocate 130 villages

8
Aswan Dam, Egypt - Nile River
www.usgs.gov/features/ satellite_images.html
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Dam Overview

• Purpose
• Flood prevention
• Power generation
• Cost 1 billion
• Completed 1970

• Height 111 m
• Reservoir
• Area 6000 km2
• Volume 169 bcm
• Power Capacity 21,000 MW

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Sedimentation in Reservoir

• Majority of sediment inflow trapped in tail end
  of reservoir
• Dead storage capacity of 31.6 bcm for 500 years
• Feasibility study being conducted for uses of
  sediments
• Lack of sediments downstream means farmers use
  13,000 t fertilizer

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Small Scale Impacts
http//www.pbs.org/wgbh/nova/
UNESCO Courier, Dec. 1964.

• Archeology
• Twin temples of Pharoah Ramses II relocated by
  UNESCO

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Small Scale Impacts

• Public Health
• Schistosomiasis associated with stagnant water
  from Dam
• Resettlement
• 90,000 Nubians displaced
• In Egypt, 28 miles away
• In Sudan, 370 miles away

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Tarbela Dam - Indus River, Pakistan
www.pakwapda.com/htmls/ water-dams.html
www.dams.org
14
Dam Overview

• Purpose
• Part of Indus Basin Irrigation System
• Irrigation
• Power generation
• Cost 1.85 billion
• Completed1993

• Height 148 m
• Reservoir
• Area 259 km2
• Volume 11.5 bcm
• Power Capacity 3478 MW

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Sedimentation in Reservoir

• Sediment inflow 0.106 bcm/yr
• Useful life 85 years
• Concern about sediments blocking power intakes in
  case of earthquake
• Underwater protection to low-level outlets
• Sediment management
• Sluicing tunnels to remove sediment
• Management measures to reduce sediment deposition
• Not feasible to reduce sediment inflow

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Small Scale Impacts

• Resettlement
• 120 villages submerged
• 96,000 people
• Replacement land in Punjab or Sindh, or cash
  compensation for home
• Widespread dissatisfaction

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References

• Three Gorges Dam
• Chinese Academy of Sciences and the Research
  Inst. For Protection of Yangtze Water Resources.
  Environmental Impact Statement for the Yangtze
  Three Gorges Project
• Nova. Damming the Past www.pbs.org/wgbh/nova/zeug
  ma/
• Aswan High Dam
• Marc Lavergne. The Seven Deadly Sins of Egypts
  Aswan High Dam
• Asit K. Biswas. Aswan Dam Revisited
• Hassan Osman. Hydro Development in Egypt -
  Lessons from High Aswan Dam
• The Aswan High Dam http//geography.about.com/libr
  ary/weekly/aa012698.htm
• Tarbela Dam
• World Commision on Dams. Pakistan The Tarbela
  Dam and Indus River Basin www.dams.org/kbase/stud
  ies/pk/pk_exec.htm
• Pakistan Water and Power Development Authority
  http//www.pakwapda.com/htmls/water-dams.html