Tidal Power In The Bay Of Fundy

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.