The Environmental and Social Impacts of Large Scale Dams

1
The Environmental and Social Impacts of Large
Scale Dams

• Tony Devencenzi
• Race, Poverty and the Environment
• Professor Raquel R. Pinderhughes
• Urban Studies Program
• San Francisco State University
• Spring 2003

The public has permission to use the material
herein, but only if author, course, university
and professor are credited
Image from http//www.photo.net/photo/pcd2882/hoo
ver-dam-aerial-91
2
Patrick McCully

• Massive dams are much more than simply machines
  to generate electricity and store water. They are
  concrete, rock and earth expressions of the
  dominant ideology of the technological age icons
  of economic development and scientific progress
  to match nuclear bombs and motor cars.

3
Introduction

• This presentation focuses on the negative impacts
  of large scale irrigation and hydroelectric dams
  from both an environmental and a social
  perspective. It is designed to describe how dams
  effect their surrounding physical environment, as
  well as their social impact on local people and
  their cultures. To do this, it focuses on the
  lifecycle of freshwater extraction at it largest
  scale through the use of gigantic concrete
  mega-dams.

4

• Life on this planet has evolved around the
  availability, movement, and quality of water.
  Like every other living being on this planet,
  water is essential for human survival. Because
  of this, civilization has traditionally been
  structured around the natural spatial arrangement
  and flow of water systems. From nomadic trade
  routes that travel from oasis to oasis, to large
  modern port cities and blooming desert
  metropolises, humanity is inseparably linked to
  water.

5
Dam Uses

• Direct Water Usage
• Private / Domestic - Household purposes, Drinking
  water and landscape irrigation
• Commercial - Restaurants, hotels, golf courses,
  etc.
• Irrigation Crop use. Water needs at the scale
  that large dams provide most often feed
  industrial farming practices.
• Livestock Use for animal raising as well as
  other on-farm needs
• Industrial Cooling water (power generation,
  refineries, chemical plants), processing water
  (manufacturing pulp and paper, food, high tech,
  etc.)
• Mining hydraulic mining, various processes,
  settling ponds
• General public supply Firefighting, public
  parks, municipal office buildings

6
Dam Uses

• Indirect Uses
• Hydroelectric Power Power generation is one of
  the most common purposes for the construction of
  large dams. It is promoted as a totally clean
  form of electricity.
• Flood Control Dams even out the peaks and lows
  of a rivers natural flow cycle by calming
  seasonal flooding, then storing that water for
  gradual release year round.
• Transportation Dam locks are used to move ships
  past large dams. This in conjunction with flood
  control make transportation feasible on rivers
  that were traditionally wild.

7
Distribution of Water Resources

• Global distribution of water resources varies
  greatly by region. Climate, topography, geology,
  hydrology, upstream water usage, and historic
  water usage all come into play in determining the
  availability of water in any given region.

From http//www.unep.org/vitalwater/a2.htm
8
Distribution of Water Resources

• This is not to say that everyone in these water
  rich areas has consistent, affordable, quality
  water that is assured to them.

Peru, The Democratic Republic of the Congo, and
Myanmar are examples of this
From http//www.worldwater.org/
9
Hmm . . . Those countries sure seem to have a lot
of water, why dont they just build lots of large
dams to fix their problems??
But with lots of large dams they could provide
water for their thirsty masses and clean
electricity to fuel industrialization! Everyone
would benefit, it would be fabulous!
Well, you see Chuck, Its not quite that simple.

Oh boy . . . I think we better start at the
beginning . . .
10
Types of Large Dams

• Large dams are built using several different
  methods. For the purpose of this project I will
  investigate the three main types of dams that can
  be built at extreme scales. These types are
• Gravity dams
• Arch dams
• Buttress dams

11
Gravity Dams

• Gravity Dams use their triangular shape and the
  sheer weight of their rock and concrete structure
  to hold back the water in the reservoir.

From http//www.dur.ac.uk/des0www4/cal/dams/conc
/gappu.htm
12
Gravity Dams

• Gravity dams are the most common type of large
  dam in the world because they are easy and cheap
  to build. They can also be built across long
  distances over relatively flat terrain. This
  makes them very applicable in non-mountainous
  regions. The largest gravity dam in the world is
  the Aswan Dam in Egypt. (24)

13
Arch Dams

• Arch Dams utilize the strength of an arch to
  displace the load of water behind it onto the
  rock walls that it is built into.

From http//www.photo.net/photo/pcd2882/hoover-da
m-aerial-91
From http//www.pbs.org/wgbh/buildingbig/dam/arch
_forces.html
14
Arch Dams

• Arch dams can only be built where the walls of a
  canyon are of unquestionable stability. They
  must also be impervious to seepage around the
  dam, as this could be a source of dam falure in
  the future. (24)
• Because of these factors, Arch dams can only be
  built in very limited locations.
• Arch dams use less materials than gravity dams,
  but are more expensive to construct due to the
  extensive amount of expertise required to build
  one. (25)

15
Buttress Dams

• Buttress Dams use multiple reinforced columns to
  support a dam that has a relatively thin
  structure. Because of this, these dams often use
  half as much concrete as gravity dams

From http//www.dur.ac.uk/des0www4/cal/dams/conc
/buttress.htm
16
Composite Dams

• Composite dams are combinations of one or more
  dam types. Most often a large section of a dam
  will be either an embankment or gravity dam, with
  the section responsible for power generation
  being a buttress or arch.

17

• The Bloemhof Dam on the Orange River of South
  Africa is an excellent example of a
  gravity/buttress dam.

Buttress Dam
Gravity Dam
From http//www.dwaf.gov.za/orange/images/web176l
.jpg
18
Wow! Thats great, now youve shown me all the
amazing techniques that I need to bring fresh
water to those people!! Yahoo! Lets Go!
Hold on there Buckaroo! You see, there are quite
a few environmental and social problems
associated with these here dams . . . Lets start
with the materials that theyre made of
19
Materials

• Large amounts of soil, sand, stone and aggregate
  and concrete are need for dam construction.
• If available, these materials will be collected
  as near to the site of the dam as possible.
• The extraction of these materials requires large
  amounts of fossil fuels to operate the machinery.
  
• Air and water pollution result from the dust and
  mud that is created from this process

20
Materials continued Concrete

• Concrete is the primary ingredient in any large
  scale dam.
• Concrete is basically a mixture of two
  components aggregates and paste. The paste is
  usually composed of Portland cement and water,
  and it binds together the fine and coarse
  aggregates. (20)
• A typical mix is about 10 to 15 cement, 60 to
  75 sand/ aggregate, 10 to 20 water and 5 to 8
  air. (20)
• Producing one ton of cement results in the
  emission of approximately one ton of CO2, created
  by fuel combustion and the calcination of raw
  materials (21)

21
Physical Impacts of Large Dams

• The physical impacts of large scale dams fall
  into several categories
• Upstream
• On-site
• Downstream
• Global Scale

22
Physical Impacts Upstream

• Loss of Land
• Destruction of peoples property in the reservoir
  zone. Loss of possible agricultural, range or
  forest lands.
• Stagnant Water Table
• Water from unnatural reservoirs seeps down into
  the water table. This excess water can overload
  the natural watertable, slowing down its flow, so
  that it ultimately may go stale. This can be
  damaging to surrounding flora, and has the
  potential to harm the well water of surrounding
  peoples.
• Habitat Destruction
• The area that is covered by the reservoir is
  destroyed, killing whatever habitat existed there
  beforehand.
• Habitat destruction also happens far upstream
  from a dam. Migratory fish can no longer travel
  upstream past large dams in order to reach their
  spawning grounds.

23
Physical Impacts On-site

• Change in Water Characteristics
• Temperature Large reservoir of water heat up as
  more water is exposed to the sun for longer
  periods of time. Aquatic life that is sensitive
  to temperature cannot adjust to this change in
  their aquatic climate.
• Salinity The rise in a rivers salinity due an
  unnatural reservoir is due to increased
  evaporation rates.
• Sediment Load Sediments that wash down the
  river settle into large reservoirs. In rivers
  that have high sediment loads this usually
  determines the life
• Nutrient content Natural nutrients build up in
  reservoirs, causing eutrophication.
• O2 content each of these elements results in a
  lower oxygen content, further harming aquatic
  life.

24
Physical Impacts On-site

• Dust, Noise pollution from Construction
• Water Pollution
• Industrial and residential pollutants, as well as
  agricultural runnoff (including high nitrate
  loads, fertilizers and pesticides). On lake
  sources such as boats and jet skis add oil and
  other chemical pollutants to waste water.
• These chemicals build up to toxic levels in
  reservoirs, especially during dry seasons when
  little water leaves.
• Habitat Destruction
• Loss of local ecosystem covered by the reservoir.
• Damage caused by improved access to humans
  roads, transmission lines, increased migration

25
Physical Impacts On-site

• Exotic species introduction
• Aggressive, non-native species of fish are often
  introduced to reservoirs for farming and sport
  fishing.
• Disease
• Vector borne diseases increase in tropical areas
  due to the creation of large areas of still
  water. This encourages mosquito breeding, the
  main vector for the transmission of malaria and
  dengue.
• Schistostomaiasis is a water borne disease that
  comes from snails that breed on the upstream side
  of dams.

26
On-Site ImpactsReservoir-Induced Seismicity

• There is a correlation between the creation of a
  large reservoir, and an increase in seismic
  activity in an area
• The physical weight of unnatural reservoirs can
  cause seismic activity. While not the direct
  cause of earthquakes, the weight of reservoirs
  can act as a trigger for seismic activity.
• Although not much direct research is available on
  the subject, the proposed explanation is that
  when the pressure of the water in the rocks
  increases, it acts to lubricate faults which are
  already under tectonic strain, but have been
  prevented from slipping by the friction of the
  rock surfaces.
• As of now, it is not accurately possible to
  predict which large dams will produce RIS or how
  much activity will be produced. Earthquakes that
  are produced as the result of dams are not
  usually major, but they still pose a major threat
  to dam stability and the safety of people living
  downstream.

27
Physical Impacts Downstream

• Flow Reduction
• The downstream impacts of the net flow reduction
  due to extraction upstream can be extensive. They
  include habitat destruction far downstream at the
  mouth of the river, natural water table
  reduction.
• Change in water characteristics
• The changes in water characteristics that are
  mentioned above continues in the water that is
  discharged downstream. The cumulative effect of
  many dams on a single river magnifies each of
  these factors.

28
In Central Asia the Aral Sea shrank by half of
its original volume after the Soviets began
diverting water for electrical generation, as
well as for cotton and other crops. Although
this may be one of the most visible example,
overextraction of water resources and the
resulting drops in local water tables are
happening worldwide.
From http//www.unep.org/vitalwater/resources.htm

29
Physical Impacts Downstream

• Change in natural flood patterns
• Natural floods inundate downstream regions with
  nutrient rich sediments. Traditional farming
  systems in countries like Egypt (the Nile) and
  Bangladesh (the Ganges) were dependant upon
  seasonal floods to wash nutrient rich sediment
  upon the lower shores of the river.
• They also seasonally clear out blocked waterways,
  which prevents larger floods from causing massive
  damage.

30
From http//www.unep.org/vitalwater/23.htm
31
Named Chinas Sorrow for its history of ruinous
floods, the Yellow River now barely trickles in
its lower reaches and in recent years has gone
dry due largely to heavy irrigation upstream.
Its not alone The once mighty Nile, Ganges, and
Colorado Rivers barely reach the sea in dry
seasons.
China
32
Social Impacts Access to Water
From http//www.unesco.org
33
India
Water flows past these squatters in gigantic
pipes on its way to high paying customers in
Delhi. Where they can, they get water from leaks
in the pipe. Otherwise they retrieve it from the
Ganges River (in the background). This water is
often of substandard quality, and seasonal floods
pose the threat of washing out this entire
settlement. (10)
34
Matamoros, Mexico
With no public funds left for waste-water
treatment plants, Matamoros canal system is
filled with raw sewage and industrial pollution.
In 2001, the overused Rio Grande dropped below
the citys water intake pipes, leaving the city
with no municipal fresh water for almost a month.
(10)
35
Social Impacts Price of Water
From http//www.city.ames.ia.us/waterweb/images/
money_1.jpg
36
A drained aquifer, an inadequate water supply
system in its outer regions, and massive amounts
of poverty have left Mexico City as one of the
most water impoverished metropolitan areas in the
world. People are forced to pay almost 200 of
what wealthy residents with existing water
connections are charged. As shown in this
picture, the water is often stored in old barrels
that had previous industrial uses. (10)
Mexico City
37
Social Impacts Quality of Water
From http//www.culliganlaredo.com/water_glass_d.
jpg
38
Santiago, Chile
By reducing the need for new water sources,
wastewater treatment plants offer a solution to
building large dams, for those who can afford it.
Worldwide, 2/3 of municipal wastewater doesnt
get treated, much less recycled. Most of it
returns to the river system, where many people
fish, drink, swim and bathe. An exception to
this case is Santiago, Chile, which plans to
treat all of its wastewater by 2009. (10)
39
Displacement

• When dams are constructed in populated areas,
  many people are forced to relocate.
• Established communities are dispersed and often
  destroyed. The communities that are forced to
  absorb the influx of displaced people are
  strained to their maximum capacity.
• The mass majority of people that are displaced by
  dam construction are poor.
• The cost of moving is often placed upon the
  people being uprooted. This is extremely hard
  for poor, marginalized people to accomplish, and
  often leaves them poorer than before. This is
  especially true for small agricultural
  communities that, now forced into the urban
  settlements and its subsequent infrastructure,
  have no viable job skills in order to provide a
  living wage for themselves.

40
Displacement

• Because of limits to space and resources, people
  are often forced to move long distances from
  their original homes. This, coupled with the
  hard transition into urban areas, often destroys
  traditional cultures.
• Because of limits to space and resources, people
  are often forced to move long distances from
  their original homes. This, coupled with the
  hard transition into urban areas, often destroys
  traditional cultures.

41
Displacement India and China

• The problems of displacement are very acute in
  countries such as the Peoples Republic of China
  (PRC) and India that are already heavily
  populated, and have been aggressively building
  dams since post WWII.
• An estimated 12.2 million people have been
  displaced over the last fifty years due to the
  PRCs dam building projects (9 a,b).
• Although the number of new dams being built in
  these countries has decreased, the size and scale
  of the projects have been increasing.
• 1.1 to 1.3 million people are expected to be
  displaced by the Three Gorges project (9a). With
  the price tag of the project at an estimated
  24.65 billion for the project alone, billions
  more are going to be spent on resettlement(26).

42

• From http//www.visionengineer.com/env/dam.jpg

43
Social Impacts International

• International water conflicts occur in regions
  where rivers cross the borders of one or more
  nations.
• Violent conflict has the possibility to occur
  when one country overdraws its share of the
  water, causing detrimental effects in the
  downstream countries
• Rivers that have ongoing conflicts
• The Nile
• The Ganges
• The River Jordan
• The Colorado
• The Parana

44
Types of Development

• Developing countries have restructured their
  economic systems to pay their debt and export
  their way to prosperity.
• To do this they are developing their water
  resources in the direction of rapid
  industrialization. In this mindset, massive
  hydroelectric dams are an absolute necessary in
  order to provide the water and electricity that
  industries need.
• In otherwise resource poor countries, this is
  seen as the only answer to achieve modernization,
  and to escape their cycle of debt.
• Once that problem has been met, then issues of
  water access and quality will be answered,
  because the country will have moved up to at
  least a 2nd world status.

45
Financial Issues

• The finance that is needed for the construction
  of large dams causes many problems around the
  world especially in poor, underdeveloped
  countries that are currently trapped in a
  painfully binding cycle of debt.
• Since large scale dams require massive amounts of
  capital investment, dam construction is one of
  the primary reasons that countries take out loans
  from international lending associations.
• Countries often take out loans to build large
  hydroelectric dams in order to improve their
  industrial infastructure. The hope is that by
  boosting their industrial sector, that they will
  boost their economy into economic prosperity.

46
Debt and International Lending Associations

• Depending on the site and the scale of the
  project, prices for each project varies greatly.
  Average costs for large projects are usually in
  the area of billions of dollars (US).
• For smaller or less developed countries this cost
  is often more than their annual GDP, and is
  absolutely insurmountable without the help of
  outside financing.
• The World Bank is the greatest single source of
  funds for large dam construction, having provided
  more than US50 billion (1992 dollars) for
  construction of more than 500 large dams in 92
  countries (27)

47
Water Privatization and Globalization

• The goal (of water invested corporations) is to
  render water a private commodity, sold and traded
  on the open market, and guaranteed for use by
  private capital through global trade and
  investment agreements. These companies do not
  view water as a social resource necessary for all
  life, but an economic resource to be managed by
  market forces-like any other commodity. (12)
• Corporate shareholders have a legal
  responsibility to maintain consistently
  increasing profits and are not concerned about
  sustainability or equity of water delivery.
• The concentration of power in the hands of a
  single corporation and the inability of
  governments to reclaim management of water
  services allows corporations to impose their
  interests on government, thereby reducing the
  democratic power of citizens.

48
The Commodification of Water

• Water promises to be to the 21st Century what
  oil was to the 20th Century The precious
  commodity that determines the wealth of nations
• Forbes Magazine, May 2000 (22)

From http//www.city.ames.ia.us/waterweb/images/
money_1.jpg
49
Major Water Companies of the World
Suez image http//fete.jeux-mathematiques.org/20
00/ Nestle Image http//www.specdoc.co.uk/port0
1.htm Vivendi Image http//www.inapg.inra.fr/etu
diants/site/contenu/evenements/Forum20Vitae/entre
prises_2002.htm Saur image http//www.saur.fr/fr/
index_fr.html Thames Image http//www.uwi.com.a
u/images/main_occ_parent_logotw.gif Bechtel
Image http//www.anomalies.net/area51/images/gen
eral/organizations/bechtel/
50
Municipal Water Control

• Some of the largest corporations dealing with the
  development and management of water
  infrastructures are Vivendi Universal, Suez,
  Bouygues-SAUR, RWE-Thames, Bechtel-United
  Utilites, and Nestle (7).
• At either the request of the government or the
  insistence of the World Bank, these corporations
  take over municipal water provision services.
• The poorer, underdeveloped outlying areas of
  cities and countries are often neglected. If the
  country requires that services be provided to
  these areas, the companies often raise prices to
  ensure that full cost recovery for their expenses
  is recovered (6).
• Once these companies are in control of water
  systems, water provision becomes commodified. The
  water is then provided on an ability-to-pay
  basis.

51
So . . .
52
What should be done?
53
Conservation

• Using aggressive conservation approaches is one
  of the easiest and most cost effective ways to
  eliminating the need for new dams. Replacing
  old, leaking infrastructures is costly on the
  front end, and most municipalities in poor
  countries lack the funds to do it.
• Different conservation techniques and
  technologies can be applied to all areas of water
  use, from industry to agriculture. What lacks in
  most countries is an incentive to conserve. With
  state subsidized water flowing to areas of
  industrialization, it is more costly for
  companies to conserve water than to waste it.
  The answer proposed by the neoliberal train of
  thought is the commercialization of water
  markets. By being forced to pay for their own
  water, people turn to conservation to reduce
  costs. This may work well for certain parts of
  the industrial and commercial sector, but local
  people can ill afford to pay for water to be
  delivered to their homes, let alone improve the
  leaking pipes in their homes.

54
Irrigation Techniques
This?
Irrigated agriculture uses up to 70 of
freshwater in some countries. Nontraditional,
Industrial methods often flood fields, loosing
much of that water to evaporation.
55
Irrigation Techniques
Or this.
Correctly used, drip irrigation places the exact
amount of water where it is needed, when it is
needed. This can reduce the amount of water
needed for irrigation anywhere from 30 to 70
56
Water Integration and Management

• Instead of providing people with an endless tap,
  demand side water management provides people with
  water when they need it in pre-planned
  quantities. This encourages conservation without
  raising costs or encouraging commodification. (8)
• Water Integration refers to integrating water
  management policies into all levels of society,
  public and private. This leads to a separation
  who has power over water utilities, and can serve
  as a system of checks and balances. (5)

57
Stop Building Large Dams

• The negative social and ecological effects of
  large scale dam building far outweighs the
  positive attributes that they bring to society.
• Instead, small dams should be built, where
  needed, in the control of those who should have
  it the people.

58
Local Control

• Local control of water systems is essential for
  feasible, equitable, and sustainable water
  resource development.
• All decisions about water must be based on
  ecosystem and watershed-based management. Only
  through this method will the ecological
  limitations of watersheds and the damages that
  dams create be realized.
• These decisions must be local in origin, as they
  directly effect the people that live in the
  watershed and the people that are receiving the
  water.
• Having no vested interest in these local
  concerns, transnational corporations are
  instrumentally detrimental to the quality, cost
  and availability of water.

59
Alternatives and Conclusions

• We may now be facing the greatest challenge of
  our time. As water is the very centerpiece of
  life, the fight against the globalization and
  commodification of water is the centerpiece in
  the fight for global, universal justice and
  equity.
• No partial, conservation oriented solution is
  going to prevent the collapse of whole societies
  and ecosystems. A radical rethinking of our
  values, priorities, and political systems is
  urgent.
• There are many ways to assist the developing
  world in this crisis, the major among these is
  the cancellation of the Third World debt.
  Without the crushing load of debt, countries
  would be able to control their own resources, and
  would not be forced into models of development
  that are not right or natural for their country.
• Water must be declared a basic human right. This
  might sound elemental, but at the World Water
  Forum in The Hague, it was the subject of heated
  debate, with the World Bank and the water
  companies seeking to have it declared a human
  need. This is not semantic. If water is a human
  need, it can be serviced by the private sector.
  You cannot sell a human right. (12)

60
We, as human beings, must change our behaviors.
We must emphasize identifying the capacity of our
watersheds and, as communities, identify the
limits we can place upon them. The world must
accept conservation as the only model for
survival, and we must all teach ourselves to live
within our environment's capacity. The insidious
problem with pricing and conservation by
commodification is that it actually undermines
environmental science and activism, as well as
governments' responsibility to protect their
citizens and the environment by buying into the
argument that the market will fix everything. At
stake is the whole notion of "the commons," the
idea that through our public institutions we
recognize a shared human and natural heritage to
be preserved for future generations. Citizens in
communities around the world must be the
"keepers" of our waterways and establish
community organizations to oversee the wise and
conservative use of this precious resource. Never
has there been such an urgent need to come to
terms with this seminal issue.
Maude Barlow
61
References

• Blue Gold the Fight to Stop the Corporate Theft
  of the Worlds Water. M. Barlow, T. Clarke. The
  New Press, New York, 2002.
• The California Water Atlas. Karl, William L. ed.
  State of California Office of Planning and
  Research, Sacramento. 1978
• Water and Water Policy in World Food Supplies.
  Articles presented at Texas AM University on May
  26-30, 1985. Texas AM University Press, College
  Station, TX. 1987
• Cadillac Desert. Mark Reisner. Penguin Books,
  New York, 1993
• Justice and Natural Resources Concepts,
  Strategies, and Applications. K. Mutz, G. Bryner
  D. Kenney. Island Press, Washington, 2002
• Silenced Rivers The Ecology and Politics of
  Large Dams. Patrick McCully, Zed Books, London,
  1996
• The Water Manifesto Arguments for a World Water
  Contract. Petrella, Riccardo. Zed Books, London,
  2001
• Integrated Approach for Efficient Water Use Case
  Study Israel Saul Arlosoroff, The World Food
  Prize International Symposium From the Middle
  East to the Middle West Managing Freshwater
  Shortages and Regional Water Security, Des
  Moines ,Iowa, USA October 24-25, 2002
• http//www.dams.org The World Commission on Dams
  homepage
• Country Review Paper Experience with Dams in
  Water And Energy Resource Development In The
  Peoples Republic of China
• Case Study Large Dams Indias Experience

62

• Montaigne, Fen. Challenges for Humanity Water
  Pressure. National Geographic. Sept. 2002
  (pictures by Peter Essick)
• http//www.irn.org The International Rivers
  Network
• http//www.foodfirst.org/pubs/backgrdrs/2001/s01v7
  n3.html
• http//water.usgs.gov/. Official page of the
  United States Geological Survey
• http//toxics.usgs.gov/. USGS Toxic Substances
  Hydrology Program
• http//www.epa.gov/water/ The official website
  of the United States Environmental Protection
  Agencys Office of Water.
• http//www.epa.gov/305b/2000report/ EPA Water
  Quality Inventory Report, 2000.
• http//www.worldbank.org/ The World Banks
  official home page.

63

• http//www.wef.org/. The Water Environment
  Federation homepage.
• http//www.thewaterpage.com/ The Water Page
• http//www.aci-int.org/general/home.asp The
  American Concrete Institute Homepage
• http//www.ecosmart.ca/resources/environmental/net
  _imp.asp
• http//www.fortune.com/fortune/investing/articles/
  0,15114,368262,00.html
• http//www.chinaonline.com/refer/ministry_profiles
  /threegorgesdam.asp
• http//www.dur.ac.uk/des0www4/cal/dams/geol/topo.
  htmgravity The University of Durham, UK
• http//www.ies.wisc.edu/research/wrm00/educ.htm
  The Nelson Institute for Environmental
  Studies, University of Wisconsin Madison
• http//www.cnn.com/EARTH/9711/08/china.3gorges/
  CNN Report on the Three Gorges Dam
• http//www.whirledbank.org/environment/dams.html
• http//www.pbs.org/now/science/bolivia.html