Bay of Fundy
Bay of Fundy, (44º45'10" North, 66º55'55" West) is a bay located on the Atlantic coast of North America, on the northeast end of the Gulf of Maine between the provinces of New Brunswick and Nova Scotia in Canada. A small portion of the northwest corner of the bay's coastline fronts the US state of Maine.
The Bay of Fundy is 290 kilometers (180 miles) in length. The mouth of the Bay of Fundy is 100 km (62 miles) wide and between 120 and 215 meters (400-700 feet) deep. It is a deep, straight-sided, somewhat funnel-shaped bay that splits at its northeastern head into two narrow bays, Chignecto Bay and the Minas Basin. It was formed as the continental plates parted millions of years ago. As they split, deep rift valleys formed, which quickly filled with sediment washed in from the land. The Bay of Fundy is one of these ancient rifts.
The name "Fundy" is thought to date back to the 16th century, when the Portuguese referred to the bay as "Rio Fundo" or "deep river". The highest tides on Earth occur in the eastern extremity of the Bay of Fundy, where the range approaches 17 meters (56 feet) when the various factors affecting the tides are in phase. More than one hundred billion kilograms (110*109 tons) of water flow into and out of the bay on an average tide, twice a day, creating a substantial potential supply of energy.
The Annapolis Tidal Generating Station, the first and only modern tidal plant in North America, was completed in 1984. Annapolis uses the largest straflo turbine in the world, which produces 20 megawatts at peak output. The facility produces more than 30 million kilowatt hours per year - enough to power about 4,500 homes - which is fed directly into the Nova Scotia Power Corporation's utility system.
The station allows the incoming tide to fill the head pond through the sluice gates. When the head pond reaches its maximum level the sluice gates are closed, trapping the water in the head pond. When the tide recedes outside of the head pond and drops by 1.6 m or more, 18 wicket gates to the distributor assembly open. The gates control the flow of the water through the turbine. When the gates are open, water flows through at the rate of 400 cubic meters per second and turns a large four-blade runner. The power generating phase lasts for approximately five hours, at which time the gates close and a new cycle begins. This is repeated twice daily.
One of the more unusual wonders of the Fundy tides is Reversing Falls, located in Saint John. This is caused by a tidal bore, a wall of water that moves up certain low-lying rivers due to an incoming tide. Tidal bores form when an incoming tide rushes up a river, developing a steep forward slope due to resistance to the tide's advance by the river, which is flowing in the opposite direction. At low tide, water rushes through the Saint John Harbor into the river, creating turbulent rapids. At high tide, the rising water of the harbor stops and then overpowers the downward flow of water in the river, such that the current runs upstream, creating rapids once again.
Source
- Cleveland, Cutler (Lead Author); Tom Lawrence (Topic Editor). 2006. "Bay of Fundy." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published September 12, 2006; Last revised November 8, 2006; Retrieved January 24, 2007]. <http://www.eoearth.org/article/Bay_of_Fundy>
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