yEnvironment Report: Tidal Power In The Bay of FundyINTRODUCTIONThe Bay of Fundy, which is found off the shores of Nova Scotia, has thehighest tides in the world . Extraordinary tides occur when the tidal wave length is two to fourtimes the length of the Bay. By virtue of blind luck or physics, the tide isamplified into a standing wave, like water sloshing in a bathtub.
For a breakingwave to form, the surging tide must meet an obstacle. When the ocean meets theriver going in the opposite direction, the sea hesitates, piles up behind thefront line, and advances anew in a tidal bore. Usually the ingredients occur during a new moon with 15 feet tides andthe opposing force of the Shubenacadie river to display the true Bay’smagnificence. 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 ofFundy tides and the currents of the St John River which flow out of the mainHabour 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 typeof tides. High – water heights vary from 22 to 28 feet and low – water heightsvary from 0 to 7 feet above chart data. Because of these semi – diurnal tidesand the action of the St John River, slack water in the Habour occurs atapproximately tides and not at high or low water as would be the case at otherparts.
THE RHYTHMIC RISE AND FALLIn the Bay of Fundy, the tides are spectacularly large. While the riseand fall of sea level due to tides is the most apparent aspect, it is also thetidal currents that direct magnification of tides, and the sea level rises ordeclines are due to resulting convergences and divergencies. These tides riseand fall over a range that is greater than 50 feet; such massive water movementcombined with accumulation of sediment through erosion has built up a large saltmarsh that is a feeding station for migrating shore birds. The low fundy alsofeeding a ground for marine life including whales. A long time ago between about15000 and 10000 year ago at the glacier retreated from the last ice age, part ofGeorges Bank were dry land. Such as fragment of trees and mammoth teeth fromthis are still found occasional in fishing travels.
The sun and the moon arethe only important celestial bodies in producing Terrestrial tides. While themoon is much smaller than the sun, it is nevertheless more important for tidalprocesses, because of its proximity to the earth. There is a small imbalancebetween the centrifugal force and the gravitational attraction of the moononthe water column that gives rise to horizontal forces, causing water motion thatcauses two bulges in the sea surface. One immediately under the earth, and theother on the other side of the earth. These bulges tend to rotate around theglobe along with the moon resetting in semi-diurnal tides with a period of halfa lunar day (12. 4 diurnal hours) even though the earth’s rotation is a diurnalperiod of 24 hours.
PROLOGUEThe Bay of Fundy is an area of about 1. 6(100000 Km2). The Bay of Fundy is apart of the Continental Shelf off eastern Canada and New England. It also servesas an extension that divides New Brunswick from Western Nova Scotia.
At the Bayof Fundy’s tidal river at the Southwestern tip of Nova Scotia, sea wateroverflows the other riverbank in spring to deposit loads of North Atlantic Salttwice daily. In the tidal river, fresh water and salt water are mixed. Fundy ofBay 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 groundfor estuary fish. It is a land that leaves even the most experienced naturalistsawestruck by the aerial ballet performed annually by thousands of birds flyingwing to wing during annual migration. The first experiment dealing with the consequences of environmental pollutionwas conducted at Yarmouth.
There was a polluted brook on a farm sullied byfoul-smelling effluent. Part of problem came from the regional airport wherenoxious run of f had spilled into the head water of the brook. This pollutionstayed in the brook for over 25 years. The area was putrid smelling from fishmeal and made people sick. TIDAL POWERThe Fundy tides are a renewable source of energy with potentially hundreds ofbillions of kilowatts generated each year.
It has the potential to provideviable energy, as there is a growing need for pollution-free sources. The Bayof Fundy tidal power has, over half a century, been sparked interest andsuccessful investigation into the potential of its development. Technologicaladvancement and “the new economy”brought renewed interest into developing energyfrom the Fundy tides. SUN AND MOONWhile the rhythmic modulation of sea level and its association with the motionof the sun and the moon must have been noticed since prehistoric time, a betterunderstanding had to wait until Sir Isacc Newton applied his theory ofgravitation to explain the underlying physical mechanism.
He was able toconstruction an equilibrium theory of tides, that explained the semi-diurnalnature of tides in most parts of the world. If there were infinite time allowedfor adjustment of the ocean to the astronomical forces it is the equilibriumtides that would be the result. This is, however, not the case since the tidalforcing varies quite rapidly with time. Resonance in the oceanic response pushtides in certain localities to be above the value predicted by the equilibriumtheory. While the equilibrium theory products two bulges to form, one underneaththe moon and the other on the opposite side of the globe, in reality the highwater may significantly precede or lag the transit of the moon.
Thesedifferences are due to the dynamic response of the oceans to tidal forcing. Itwas Laplace who a century later laid the theoretical and mathematical foundationfor modern dynamic theory of ocean tides by considering oceanic tides to be theresponse of a fluid medium to the astronomical forcing by the sun and moon’sgravitational attractions. THE OIL OF FUNDY BAYThe transportation of oil from the Bay of Fundy and the generation of nuclearpower are two aspects of the same issue in that the supply of energy thatpresent inherent risks to the environment, but opposing arguments against theuse 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 Marineorganisms and the coastal environment is always a possibility. TIDAL POWER OF ELECTRICAL ENERGYThe monumental Mains Basin scheme produces more than twice as much electricityin Nova Scotia at 4560 megawatts from all sources-coal, oil and hydro as thelargest water-driven electrical power plant in the world.
Nova Scotia producesmore power than Newfoundland’s Churchill Falls (about 2660 megawatts) andOntario Hydro’s Picketing nuclear-power plant ( 2160 megawatts). Tidal powerwould not replace conventional electrical energy derived from nuclear or fossilfuels for peak demand. Tidal power has fluctuating peaks so. At 12 noon is whenyou need the power might not be quailabler.
Utilities would still meet peakdemand whether or not tidal power was on the line. The renewable energy sourceusing 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 electricityless than 40% of the generating capacity of a river dam. TIDAL POWER AND THE MILLIn the 15 century, a construction handbook was published ,showing how tidalwater was held behind a dam at high tide so that when a sufficient water levelwas reached between the land and sea sides of the dam . a mill could use tidalwater to mix with the fresh water to turn the waterwheel that provided power forgrinding grain.
The first mill in the would was built in 1607 by Samuel deChamplain on the Lequille River. By 1910 Turnbull and an American engineer,designed a double basin scheme that would cross the international boundarybetween New Brunswick and Maine. CONCLUSIONGiven the grave environmental challenges such as global warning or environmentalpollution facing many kind in the coming century and because oceans play such avery important role in governing the degree of global warming, fisheries yield,and degrees of pollution along our beaches, the study of the tides through avariety of means such as ship surveys, and remote sensing will lead to a betterunderstanding of how the oceans work. The hope is that as a result, we willleave behind for our children a world that is both livable as well as enjoyablein all its majesty .
If we an avoid oil spills into the ocean the water andenvironment will be more beautiful and ecologically safe for all living things.Social Issues
