Environment Report: Tidal Power In The Bay of Fundy




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