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          ARRoGANT                CoURiERS      WiTH     ESSaYS

Grade Level:       Type of Work           Subject/Topic is on:
 [ ]6-8                 [ ]Class Notes    [Essay on the Effects of ]
 [ ]9-10                [ ]Cliff Notes    [Damn Building           ]
 [x]11-12               [x]Essay/Report   [                        ]
 [ ]College             [ ]Misc           [                        ]

 Dizzed: 09/94  # of Words:1236  School: ?              State: ?
ФФФФФФФФФ>ФФФФФФФФФ>ФФФФФФФФФ>Chop Here>ФФФФФФФФФ>ФФФФФФФФФ>ФФФФФФФФФ>ФФФФФФФФФ
                            Grade 10 Geography
                             Units 12, 13, 14
                      Essay - Effects of Dam Building

   Many people have already dammed a small stream using sticks and mud by
the time they become adults. Humans have used dams since early
civilization, because four-thousand years ago they became aware that floods
and droughts affected their well-being and so they began to build dams to
protect themselves from these effects.1 The basic principles of dams still
apply today as they did before; a dam must prevent water from being passed.
Since then, people have been continuing to build and perfect these
structures, not knowing the full intensity of their side effects. The
hindering effects of dams on humans and their environment heavily outweigh
the beneficial ones. The paragraphs below will prove that the construction
and presence of dams always has and will continue to leave devastating
effects on the environment around them.

   Firstly, to understand the thesis people must know what dams are. A dam
is a barrier built across a water course to hold back or control water
flow. Dams are classified as either storage, diversion or detention. As you
could probably notice from it's name, storage dams are created to collect
or hold water for periods of time when there is a surplus supply. The water
is then used when there is a lack of supply. For example many small dams
impound water in the spring, for use in the summer dry months. Storage dams
also supply a water supply, or an improved habitat for fish and wildlife;
they may store water for hydroelectricity as well.2

   A diversion dam is a generation of a commonly constructed dam which is
built to provide sufficient water pressure for pushing water into ditches,
canals or other systems. These dams, which are normally shorter than
storage dams are used for irrigation developments and for diversion the of
water from a stream to a reservoir. Diversion dams are mainly built to
lessen the effects of floods and to trap sediment.3

   Overflow dams are designed to carry water which flow over thier crests,
because of this they must be made of materials which do not erode. Non-
overflow dams are built not to be overtopped, and they may include earth or
rock in their body. Often, two types of these dams are combined to form a
composite structure consisting of for example an overflow concrete gravity
dam, the water that overflows into dikes of earthfill construction.4

    A dam's primary function is to trap water for irrigation. Dams help to
decrease the severity of droughts, increase agricultural production, and
create new lands for agricultural use. Farmland, however, has it's price;
river bottomlands flooded, defacing the fertility of the soil. This
agricultural land may also result in a loss of natural artifacts. Recently
in Tasmania where has been pressure from the government to abandon the
Franklin project which would consume up to 530 sq miles of land listed on
the UN World Heritage register. In the land losses whole communties must
leave everything and start again elsewhere.5

   The James's Bay Hydroelectric project, hailed to be one of the most
ambitious North American undertaking of dams was another example of the
lands that may be lost. The 12.7 billion scheme was to generate 3 160
megawatts of electricity a day, this power output would be enough to serve
a city of 700 000! One of the largest problems with this dam, is that it
would be built on a region that meant a lot to 10 500 Cree and 7 000 Inuit.
Lands that their ancestors have hunted and lived on for more than 5 000
years will be flooded along with 90% of their trapping lines.6 If this
happened these people must resettle, find a new way of life and face the
destruction of a piece of their heritage if this project is approved.

    When a dam is being constructed, the river where it is supposed to be
built on must be drained. This kills much of the life and disrupts the
ecosystem and peaceful being of all the aquatic and terrestrial animals
around it. At fisheries there is a large impact on the fish. The famous
Columbia River saw it's stock of salmon drop considerably after the dams
were built, although there were fish ladders built. The salmon were unable
to swim upstream when it was time for breeding as they usually did.7

   But perhaps it is the plans for the Amazon Basin in Brazil that shows us
how large the side-effects can be. In the city Surinam, in northern Brazil,
Lake Brokopondo was created in 1864 swamping about 580 square miles of
virgin rainforest. Foul smelling gas called hydrogen sulfide was produced
as the trees decomposed. The turbine casings were attacked by the acidic
water and the decay of water allowed a chance for hyacinths to float on the
surface. This did not allow the light to shine through to the water onto
the plants which the fish feeded on. The plants were unable to perform
photosynthesis, and the fish died also because there was a lack of food. In
the lack of sun the waterweeds grew and threaten to create diseases such as
malaria, where the whole lake's ecosystem would die out.8 Many little
animals and plants which were never discoved and may have had high economic
value were to be lost forever.

  There remains a problem with reservoirs which to date hasn't been solved
yet. A reservoir is a to store water, mainly for hydroelectric power or
irrigation. Nearly 10 000 caribou drowned while crossing the inflated
Caniapiscau River in September 1984, because of these reserviors. The heavy
rainfall created enough water to overtop the structure and caused extra
amounts of spillages in the reservoir. The water flooded the river while
the caribou were literally submerged.9

   The Colarado River, known as the most litigated, controlled and lesgislated
river in the world. People who used to raft there now say it is very insafe
because of the fluctuating surges of water meant to accomodate when the people
use most energy. What was fresh water is now being converted to salty water
because of these reservoirs. The water standing in the reservoir evaporates
when not used and the rest of the water becomes more salty.10

  There is another theory that dams are causing earthquakes, when these large
structures are placed with the mass of the unnatural weight of the lake near
it, this disrupts the Earth's surface and is a new precaution where before it
was never heard of. Many people say that dams protect people from natural
disasters, but there are some which it can intensify. For instance if an
Earthquake happens then, along with cracks in the ground, buildings falling,
there would also be a flood and large pieces of the broken dam to cope with.11

   Dams are harming the environment that people live in. What was being hailed 
as great accomplishments are now showing signs of great consquence. The
preservation of our environment is the key to the preservation of people. We
cannot exchange money for the deterioration of our own animals, plants and
land. The is the environmental age and humans must respond by changing their
ways and looking at the long-term prospect instead of the short-term. Until we
as the users and protectors of the land can do this, future of our great human
civilization will continue to look grim.
