Essay About Effects Of Dam Building And Jamess Bay Hydroelectric Project

Effects of Dam Building
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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 its 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 their
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 dams 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 its 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 Jamess 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