| Essay, Research Paper
Environment Report: Tidal Power In The Bay of Fundy
Prepared for Bill Andrson
Professor at St.Lawrence College for Environmental Science.
By
November 22,1996
INTRODUCTION
The Bay of Fundy, which is found off the shores of Nova Scotia, has the
highest tides in the world .
Extraordinary tides occur when the tidal wave length is two to four
times the length of the Bay. By virtue of blind luck or physics, the tide is
amplified into a standing wave, like water sloshing in a bathtub. For a breaking
wave to form, the surging tide must meet an obstacle. When the ocean meets the
river going in the opposite direction, the sea hesitates, piles up behind the
front line, and advances anew in a tidal bore.
Usually the ingredients occur during a new moon with 15 feet tides and
the opposing force of the Shubenacadie river to display the true Bay’s
magnificence.
This part of St. John is divided into 3 main areas: the main Harbor,
Courtenay Bay and the Outer Harbor. These areas are influenced by the Bay of
Fundy tides and the currents of the St John River which flow out of the main
Habour into the Bay.
This section also experiences two high and two low tides each day (semi
- diurnal), with a tidal range varying from 15 to 18 feet, depending on the type
of tides. High – water heights vary from 22 to 28 feet and low – water heights
vary from 0 to 7 feet above chart data. Because of these semi – diurnal tides
and the action of the St John River, slack water in the Habour occurs at
approximately tides and not at high or low water as would be the case at other
parts.
THE RHYTHMIC RISE AND FALL
In the Bay of Fundy, the tides are spectacularly large. While the rise
and fall of sea level due to tides is the most apparent aspect, it is also the
tidal currents that direct magnification of tides, and the sea level rises or
declines are due to resulting convergences and divergencies. These tides rise
and fall over a range that is greater than 50 feet; such massive water movement
combined with accumulation of sediment through erosion has built up a large salt
marsh that is a feeding station for migrating shore birds. The low fundy also
feeding a ground for marine life including whales. A long time ago between about
15000 and 10000 year ago at the glacier retreated from the last ice age, part of
Georges Bank were dry land. Such as fragment of trees and mammoth teeth from
this are still found occasional in fishing travels. The sun and the moon are
the only important celestial bodies in producing Terrestrial tides. While the
moon is much smaller than the sun, it is nevertheless more important for tidal
processes, because of its proximity to the earth. There is a small imbalance
between the centrifugal force and the gravitational attraction of the moon on
the water column that gives rise to horizontal forces, causing water motion that
causes two bulges in the sea surface. One immediately under the earth, and the
other on the other side of the earth. These bulges tend to rotate around the
globe along with the moon resetting in semi-diurnal tides with a period of half
a lunar day (12.4 diurnal hours) even though the earth’s rotation is a diurnal
period of 24 hours.
PROLOGUE
The Bay of Fundy is an area of about 1.6(100000 Km2). The Bay of Fundy is a
part of the Continental Shelf off eastern Canada and New England. It also serves
as an extension that divides New Brunswick from Western Nova Scotia. At the Bay
of Fundy’s tidal river at the Southwestern tip of Nova Scotia, sea water
overflows the other riverbank in spring to deposit loads of North Atlantic Salt
twice daily. In the tidal river, fresh water and salt water are mixed. Fundy of
Bay is famous for its tides which is the best and highest in the whole world.
The marsh is a home to mammals, a breeding place for birds and a feeding ground
for estuary fish. It is a land that leaves even the most experienced naturalists
awestruck by the aerial ballet performed annually by thousands of birds flying
wing to wing during annual migration.
The first experiment dealing with the consequences of environmental pollution
was conducted at Yarmouth. There was a polluted brook on a farm sullied by
foul-smelling effluent. Part of problem came from the regional airport where
noxious run of f had spilled into the head water of the brook. This pollution
stayed in the brook for over 25 years. The area was putrid smelling from fish
meal and made people sick.
TIDAL POWER
The Fundy tides are a renewable source of energy with potentially hundreds of
billions of kilowatts generated each year. It has the potential to provide
viable energy, as there is a growing need for pollution-free sources. The Bay
of Fundy tidal power has, over half a century, been sparked interest and
successful investigation into the potential of its development. Technological
advancement and “the new economy”brought renewed interest into developing energy
from the Fundy tides.
SUN AND MOON
While the rhythmic modulation of sea level and its association with the motion
of the sun and the moon must have been noticed since prehistoric time, a better
understanding had to wait until Sir Isacc Newton applied his theory of
gravitation to explain the underlying physical mechanism. He was able to
construction an equilibrium theory of tides, that explained the semi-diurnal
nature of tides in most parts of the world. If there were infinite time allowed
for adjustment of the ocean to the astronomical forces it is the equilibrium
tides that would be the result. This is, however, not the case since the tidal
forcing varies quite rapidly with time. Resonance in the oceanic response push
tides in certain localities to be above the value predicted by the equilibrium
theory. While the equilibrium theory products two bulges to form, one underneath
the moon and the other on the opposite side of the globe, in reality the high
water may significantly precede or lag the transit of the moon. These
differences are due to the dynamic response of the oceans to tidal forcing. It
was Laplace who a century later laid the theoretical and mathematical foundation
for modern dynamic theory of ocean tides by considering oceanic tides to be the
response of a fluid medium to the astronomical forcing by the sun and moon’s
gravitational attractions.
THE OIL OF FUNDY BAY
The transportation of oil from the Bay of Fundy and the generation of nuclear
power are two aspects of the same issue in that the supply of energy that
present inherent risks to the environment, but opposing arguments against the
use of foreign oil and nuclear power might be base on purely economic grounds.
The risk of oil spills with catastrophic and long lasting effects on Marine
organisms and the coastal environment is always a possibility.
TIDAL POWER OF ELECTRICAL ENERGY
The monumental Mains Basin scheme produces more than twice as much electricity
in Nova Scotia at 4560 megawatts from all sources-coal, oil and hydro as the
largest water-driven electrical power plant in the world. Nova Scotia produces
more power than Newfoundland’s Churchill Falls (about 2660 megawatts) and
Ontario Hydro’s Picketing nuclear-power plant ( 2160 megawatts). Tidal power
would not replace conventional electrical energy derived from nuclear or fossil
fuels for peak demand. Tidal power has fluctuating peaks so. At 12 noon is when
you need the power might not be quailabler. Utilities would still meet peak
demand whether or not tidal power was on the line. The renewable energy source
using lunar gravitation and hydroelectricity has become increasingly important.
Compared with a river dam, tidal power has a difficult saltwater environment,
where machines are needed to produce of power and also have saltwater durability.
The electric power output is the twice-daily ebb average of tidal electricity
less than 40% of the generating capacity of a river dam.
TIDAL POWER AND THE MILL
In the 15 century, a construction handbook was published ,showing how tidal
water was held behind a dam at high tide so that when a sufficient water level
was reached between the land and sea sides of the dam . a mill could use tidal
water to mix with the fresh water to turn the waterwheel that provided power for
grinding grain. The first mill in the would was built in 1607 by Samuel de
Champlain on the Lequille River. By 1910 Turnbull and an American engineer,
designed a double basin scheme that would cross the international boundary
between New Brunswick and Maine.
CONCLUSION
Given the grave environmental challenges such as global warning or environmental
pollution facing many kind in the coming century and because oceans play such a
very important role in governing the degree of global warming, fisheries yield,
and degrees of pollution along our beaches, the study of the tides through a
variety of means such as ship surveys, and remote sensing will lead to a better
understanding of how the oceans work. The hope is that as a result, we will
leave behind for our children a world that is both livable as well as enjoyable
in all its majesty . If we an avoid oil spills into the ocean the water and
environment will be more beautiful and ecologically safe for all living things.
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