Lake Ontario
The lake seen from Dutch Street Road, Huron, New York
Lake Ontario and the other Great Lakes
Location	North America
Group	Great Lakes
Coordinates	43°42′N 77°54′W / 43.7°N 77.9°W / 43.7; -77.9Coordinates: 43°42′N 77°54′W / 43.7°N 77.9°W / 43.7; -77.9
Primary inflows	Niagara River
Primary outflows	St. Lawrence River
Catchment area	24,720 sq mi (64,030 km2)[1]
Basin countries	United States  Canada
Max. length	193 mi (311 km)[2]
Max. width	53 mi (85 km)[2]
Surface area	7,340 sq mi(18,960 km2)[1]
Average depth	283 ft (86 m)[2][3]
Max. depth	802 ft (244 m)[2][3]
Water volume	393 cu mi (1,640 km3)[2]
Residence time	6 years
Shore length1	712 mi (1,146 km)[1]
Surface elevation	243 ft (74 m)[2]
Settlements	Toronto, Hamilton, Ontario, Rochester, New York
References	[3]
1 Shore length is not a well-defined measure.

Lake Ontario (French: Lac Ontario) is one of the five Great Lakes of North America. It is bounded on the north and southwest by the Canadian province of Ontario, and on the south by the American state of New York. Ontario, Canada's most populous province, was named for the lake. In the Wyandot (Huron) language, ontarío means “Lake of Shining Waters”. It is the last in the Great Lakes chain and serves as the outlet to the Atlantic Ocean via the St. Lawrence River. Lake Ontario is also the only one of the five Great Lakes not to share a coast with the state of Michigan.

Geography[link]

Lake Ontario is the easternmost of the Great Lakes and the smallest in surface area (7,340 sq mi, 18,960 km²),^[1] although it exceeds Lake Erie in volume (393 cu mi, 1,639 km³). It is the 14th largest lake in the world. When its islands are included, the lake has a shoreline that is 712 miles (1,146 km) long. As the last lake in the Great Lakes' hydrologic chain, Lake Ontario has the lowest mean surface elevation of the lakes at 243 feet (74 m)^[2] above sea level; 326 feet (99 m) lower than its neighbor upstream. Its maximum length is 193 statute miles (311 km; 168 nmi) and its maximum width is 53 statute miles (85 km; 46 nmi).^[2] The lake's average depth is 47 fathoms 1 foot (283 ft; 86 m), with a maximum depth of 133 fathoms 4 feet (802 ft; 244 m).^[2][3] The lake's primary source is the Niagara River, draining Lake Erie, with the St. Lawrence River serving as the outlet. The drainage basin covers 24,720 square miles (64,030 km²).^[1][4] As with all the Great Lakes, water levels change both within the year (owing to seasonal changes in water input) and among years (owing to longer term trends in precipitation). These water level fluctuations are an integral part of lake ecology, and produce and maintain extensive wetlands^[5][6]. The lake also has an important freshwater fishery, although it has been negatively affected by factors including over-fishing, water pollution and invasive species^[7].

Baymouth bars built by prevailing winds and currents have created a significant number of lagoons and sheltered harbors, mostly (but not limited to) Prince Edward County, Ontario and the easternmost shores. Perhaps the best-known example is Toronto Bay, chosen as the site of the Upper Canada (Ontario) capital for its strategic harbour. Other prominent examples include Hamilton Harbour, Irondequoit Bay, Presqu'ile Bay, and Sodus Bay. The bars themselves are the sites of long beaches, such as Sandbanks Provincial Park and Sandy Island Beach State Park. These sand bars are often associated with large wetlands, which support large numbers of plant and animal species, as well as providing important rest areas for migratory birds^[8][9]. Presqu'ile, on the north shore of Lake Ontario, is particularly significant in this regard. One unique feature of the lake is the Z-shaped Bay of Quinte which separates Prince Edward County from the Ontario mainland, save for a 2-mile (3.2 km) isthmus near Trenton; this feature also supports many wetlands and aquatic plants, as well as associated fisheries.

Major rivers draining into Lake Ontario include the Don River; Humber River; Trent River; the Cataraqui River; the Genesee River; the Oswego River; the Black River; and the Salmon River.

Geology[link]

The lake basin was carved out of soft, weak Silurian-age rocks by the Wisconsin ice sheet during the last ice age. The action of the ice occurred along the pre-glacial Ontarian River valley which had approximately the same orientation as today's basin. Material that was pushed southward by the ice sheet left landforms such as drumlins, kames, and moraines, both on the modern land surface and the lake bottom,^[10] reorganizing the region's entire drainage system. As the ice sheet retreated toward the north, it still dammed the St. Lawrence valley outlet, so that the lake surface was at a higher level. This stage is known as Lake Iroquois. During that time the lake drained through present-day Syracuse, New York into the Mohawk River, thence to the Hudson River and the Atlantic. The shoreline created during this stage can be easily recognized by the (now dry) beaches and wave-cut hills 10 to 25 miles (15 to 40 km) from the present shoreline.

When the ice finally receded from the St. Lawrence valley, the outlet was below sea level, and for a short time the lake became a bay of the Atlantic Ocean, in association with the Champlain Sea. Gradually the land rebounded from the release of the weight of about 6,500 feet (2,000 m) of ice that had been stacked on it. It is still rebounding about 12 inches (30 cm) per century in the St. Lawrence area. Since the ice receded from the area last, the most rapid rebound still occurs there. This means that the lake bed is gradually tilting southward, inundating the south shore and turning river valleys into bays. Both north and south shores experience shoreline erosion, but the tilting amplifies this effect on the south shore, causing loss to property owners.

History[link]

Toronto from the bay in 1901. A then heavily industrialized and busy harbour has been mostly replaced with condominium high-rise developments and urban parks.

Name[link]

Map of Lac de Frontenac (now Lake Ontario), showing Teiaiagon and Lac Taronto (now Lake Simcoe).

The lake was previously identified in some maps under different French names. In 1632 and 1656 is was referred to as Lac de St. Louis or Lake St. Louis by Samuel de Champlain and cartographer Nicolas Sanson respectively (likely for Louis XIV of France)^[11] In 1660 Jesuit historian Francis Creuxius coined the name Lacus Ontarius. In a map drawn in the Relation des Jésuites (1662–1663), the lake bears the legend "Lac Ontario ou des Iroquois" with the name "Ondiara" in smaller type. A French map produced in 1712 (currently in the Canadian Museum of Civilization^[12]), created by military engineer Jean-Baptiste de Couagne, identified Lake Ontario as "Lac Frontenac". Iroquois people called the lake "Skanadario".

17th to 20th centuries[link]

The lake was a border between the Huron and their vassals and the Iroquois Confederacy in pre-European times. The first documented European to reach the lake was Étienne Brûlé in 1615. Artifacts which are believed to be of Norse origin have been found in the area of Sodus Bay, indicating possible earlier visits by Europeans, but this remains unproven. A series of trading posts was established by both the British and French, such as Fort Oswego in 1722 and Fort Rouillé (Toronto) in 1750. After the French and Indian War, all forts around the lake were under British control. The United States did not take possession of forts on present-day American territory until the signing of the Jay Treaty in 1794. Permanent, non-military European settlement began during the American Revolution. As the easternmost and nearest lake to the Atlantic seaboard of Canada and the United States, population centres here are among the oldest in the Great Lakes basin, with Kingston, formerly the capital of Canada, dating to the 1780s. The lake became a hub of commercial activity following the War of 1812 with canal building on both sides of the border and heavy travel by lake steamers. Steamer activity peaked in the mid-19th century before competition from railway lines.

In the late 19th and early 20th centuries, a type of scow known as a stonehooker was in operation on the north-west shore, particularly around Port Credit and Bronte. Stonehooking was the practice of raking flat fragments of Dundas shale from the shallow lake floor of the area for use in construction, particularly in the growing city of Toronto.^[13]

Ecology and environmental concerns[link]

The Great Lakes watershed is a region of high biodiversity, and Lake Ontario is important for its diversity of birds, fish, reptiles amphibians and plants[1][2]. Many of these special species are associated with shorelines, particularly sand dunes, lagoons, and wetlands. The importance of wetlands to the lake has been appreciated, and many of the larger wetlands have protected status. However, these wetlands are changing in part because the natural water level fluctuations have been reduced. Many wetland plants are dependent upon low water levels to reproduce^[14]. When water levels are stabilized, the area and diversity of the marsh is reduced. This is particularly true of meadow marsh (also known as wet meadow wetlands); in Eel Bay near Alexandria Bay, regulation of lake levels has resulted in large losses of wet meadow ^[15]. Often this is accompanied by invasion by cattails, which displace many of the native plant species and reduce plant diversity. Eutrophication may accelerate this process by providing nitrogen and phosphorus for the more rapid growth of competitively dominant plants^[16]. Similar effects are occuring on the north shore, in wetlands such as Presqu'ile, which have interdunal wetlands called pannes, with high plant diversity and many unusual plant species^[17].

Most of the forests around the lake are deciduous forests that are classified as part of the Great Lakes Ecoregion. Deforestation in the vicinity of the lake has also had considerable negative impacts^[18], with loss of forest birds, extinction of native salmon, and increased amounts of sediment flowing into the lake. Guidelines for restoration stress the importance of maintaining and restoring forest cover, particularly along streams and wetlands^[19][20].

The open water is less affected by shoreline features, such as wetlands, and more affected by nutrient levels that control the production of algae. Algae are the basis of the open water food web, and the source of primary production that ends up as Lake Trout and Walleye at the top of the open water food web.File:Lake Ontario food web.pdfThis food web has been damaged not only by over-fishing, and changes in nutrient levels, but also by other types of polluted from industrial chemicals, agricultural fertilizers, untreated sewage, phosphates, such as from laundry detergents, and chemicals. Some pollutant chemicals that have been found in the lake include DDT, benzo[a]pyrene and other pesticides; PCBs, aramite, chromium, lead, mirex, mercury, and carbon tetrachloride.

By the 1960s and 1970s, the increased pollution caused frequent algal blooms to occur in the summer^[21]. These blooms killed large numbers of fish, and left decomposing piles of filamentous algae and dead fish along the shores^[22]. At times the blooms became so thick that waves could not break. Fish eating birds such as osprey, bald eagle and cormorant were being poisoned by contaminated fish. Since the 1960s and 1970s, environmental concerns have forced a cleanup of industrial and municipal wastes. Cleanup has been accomplished through better treatment plants, tighter environmental regulations, deindustrialization and increased public awareness. Today, Lake Ontario has recovered some of its pristine quality but regional airshed pollution remains a concern. For example, walleye, a fish species considered as a marker of clean water, are now found. The lake has also become an important sport fishery, although with introduced species (Coho and Chinook salmon) rather than the native species. Bald eagle and osprey populations are also beginning to recover.

Invasive species are a problem for Lake Ontario, particularly lamprey and zebra mussels. Lamprey are being controlled by poisoning in the juvenile stage in the streams where they breed. Zebra mussels in particular are difficult to control, and pose major challenges for the lake and its waterways.

Thermal pollution from the Pickering Nuclear Generating Station and Darlington Nuclear Generating Station just east of Toronto has become a concern in recent years, with the warm wastewater released from the plant being a problem year-round.^[23] Radioactive and heavy metal contamination from these nuclear plants, as well as nuclear-industry fuel manufacturing in Port Hope, Ontario, is also an ongoing concern.

Climate[link]

Lake Ontario as seen from the top of the CN Tower

The lake has a natural seiche rhythm of eleven minutes. The seiche effect normally is only about ¾ inches (2 cm) but can be greatly amplified by earth movement, winds, and atmospheric pressure changes.

Because of its great depth, the lake as a whole never freezes in winter, but an ice sheet covering between 10% and 90% of the lake area typically develops, depending on the severity of the winter. Ice sheets typically form along the shoreline and in slack water bays, where the lake is not as deep. During the winters of 1877 and 1878, the ice sheet coverage was up to 95–100% in most of the lake. In the winter of 1812, the ice cover was stable enough that the American naval commander stationed at Sackets Harbor feared a British attack from Kingston, over the ice.

When the cold winds of winter pass over the warmer water of the lake, they pick up moisture and drop it as lake-effect snow. Since the prevailing winter winds are from the northwest, the southern and southeastern shoreline of the lake is referred to as the snowbelt. In some winters the area between Oswego and Pulaski may receive twenty or more feet (600 cm) of snowfall. Also impacted by lake-effect snow is the Tug Hill Plateau, an area of elevated land that is about 20 miles (32 km) east of Lake Ontario, creating ideal conditions for lake-effect snowfall. The "Hill", as it is often referred to, typically receives more snow than any other region in the eastern United States. As a result, Tug Hill is a popular location for winter enthusiasts, such as snow-mobilers and cross-country skiers. Lake-effect snow often extends inland as far as Syracuse, with that city often recording the most winter snowfall accumulation of any large city in the United States. Other cities in the world receive more snow annually, such as Quebec City, which averages 135 inches (340 cm), and Sapporo, Japan, which receives 250 inches (640 cm) each year and is often regarded as the snowiest city in the world. Foggy conditions (particularly in fall) can be created by thermal contrasts and can be an impediment for recreational boaters. In a normal winter, Lake Ontario will be at most one quarter ice-covered, in a mild winter almost completely unfrozen. Lake Ontario has completely frozen over on five recorded occasions: from about January 20 to about March 20, 1830^[24]; in 1874^[25]; in 1893^[26]; in 1912^[27]; and in February 1934.^[28]

Lake breezes in spring tend to retard fruit bloom until the frost danger is past, and in the autumn delay the onset of fall frost, particularly on the south shore. Cool onshore winds also retard early bloom of plants and flowers until later in the spring season, protecting them from possible frost damage. Such microclimatic effects have enabled tender fruit production in a continental climate, with the southwest shore supporting a major fruit-growing area. Apples, cherries, pears, plums, and peaches are grown in many commercial orchards around Rochester. Between Stoney Creek and Niagara-on-the-Lake on the Niagara Peninsula is a major fruit-growing and wine-making area. The wine-growing region extends over the international border into Niagara and Orleans counties. Apple varieties that tolerate a more extreme climate are grown on the lake's north shore, around Cobourg.

Settlements[link]

A large conurbation called the Golden Horseshoe occupies the lake's westernmost shores, anchored by the cities of Toronto and Hamilton. Ports on the Canadian side include St. Catharines, Oshawa, Cobourg and Kingston, near the St. Lawrence River outlet. Close to 9 million people or over a quarter of Canada's population lives within the watershed of Lake Ontario. The American shore is largely rural, with the exception of Rochester and the much smaller ports at Oswego and Sacket's Harbor. The city of Syracuse is 40 miles (64 km) inland, connected to the lake by the New York State Canal System. Over 2 million people live in Lake Ontario's American watershed.

A high-speed passenger/vehicle ferry, the Spirit of Ontario I, operated between Toronto and Rochester from 17 June 2004 to 10 January 2006, when the service was cancelled. The Crystal Lynn II, out of Irondequoit, New York has been operating between Irondequoit Bay and Henderson, New York since May 2000, operated by Capt. Bob Tein.

Winter scene on Toronto Bay in 1835

Toronto Harbour in 2007

Ocean and lake navigation[link]

The Great Lakes Waterway connects the lake sidestream to the Atlantic Ocean via the St. Lawrence Seaway, and upstream to the other rivers in the chain via the Welland Canal and to Lake Erie. The Trent-Severn Waterway for pleasure boats connects Lake Ontario at the Bay of Quinte to Georgian Bay (Lake Huron), via Lake Simcoe. The Oswego Canal connects the lake at Oswego to the New York State Canal System, with outlets to the Hudson River, Lake Erie, and Lake Champlain.

The Rideau Canal, also for pleasure boats, connects Lake Ontario at Kingston to the Ottawa River in downtown Ottawa.

Lighthouses[link]

• Braddock Point Light
• Charlotte-Genesee Lighthouse
• Gibraltar Point Lighthouse
• Oswego Harbor West Pierhead Light
• Sodus Point Light
• Stony Point Light
• Presqui'le Lighthouse
• Thirty Mile Point Light

Islands[link]

British gunboats capture French corvette L'Outaouaise during the Battle of the Thousand Islands in 1760.

Several of the thousand islands viewed from New York toward Ontario

Nearly all of Lake Ontario's islands are located on the eastern and north-eastern shores, between the Prince Edward County headland and the lake's outlet at Kingston. The Toronto Islands on the north-western shore are the remnants of a sand spit formed by coastal erosion, whereas the mostly larger eastern islands are underlain by the basement rock found throughout the region. The Thousand Islands, mostly found in the St. Lawrence River, have several large members near the Lake Ontario side of the outlet. Wolfe Island, located near Kingston at the St. Lawrence outlet, is the largest island in the basin. It is accessible by ferry from both Canada and the U.S.

• Thousand Islands
• Toronto Islands – only island on the western end of the lake
• Association Island
• Galloo Island
• Amherst Island
• Simcoe Island
• Garden Island
• Grenadier Island
• Waupoos Island
• Nicholson Island
• Big Island

Other topics[link]

The Great Lakes Circle Tour and Seaway Trail are designated scenic road systems connecting all of the Great Lakes and the St. Lawrence River.^[29]As the Seaway Trail is posted on the US side only, Lake Ontario is the only of the five Great Lakes to have no posted bi-national circle tour.

In the 1800s, there were reports of an alleged creature similar to the so-called Loch Ness Monster being sighted in the lake. The creature is described as large with a long neck, green in colour, and generally causes a break in the surface waves.^[30][31][32]

Images[link]

• 

  Lake Ontario in its context. Note green of Adirondack forests to right.

• 

  The lake seen from dead end of Dutch St.; Huron, New York (A sparsely populated neighboring town of Wolcott, New York)

• 

  Pier 4 Park, Hamilton, Ontario

• 

  Beach seen from Toronto, Ontario's Humber Bay, west of downtown

• 

  Sandbanks Provincial Park

• RobertKafarski OntarioLakeWinter Toronto.jpg

  From Toronto lakeshore in winter

• 

  A glimpse of Lake Ontario

• Toronto from LO.JPG

  The Toronto skyline viewed from across Lake Ontario (Niagara-on-the-Lake, Ontario)

• 

  Bathers at Southwick Beach State Park, eastern shore of Lake Ontario, New York State

See also[link]

• Lake Ontario Waterkeeper
• Glacial Lake Iroquois
• Glacial Lake Admiralty
• Welland Canal
• Engagements on Lake Ontario
• Bay of Quinte
• Niagara River
• St. Lawrence River
• United Empire Loyalist
• Fort Niagara
• Wyandot people
• Iroquois Confederacy
• Ontario Lacus, a hydrocarbon-lake on Saturn's moon Titan named after Lake Ontario

Great Lakes in general[link]

References[link]

External links[link]

Wikimedia Commons has media related to: Lake Ontario

• Lake Ontario NOAA nautical chart #14820 online
• Lake Ontario United
• Lake Ontario Waterkeeper
• EPA's Great Lakes Atlas
• Great Lakes Coast Watch
• Pollution in the Great Lakes
• Lake Ontario Bathymetry
• The Problem of Vinland (Norsemen on Lake Ontario)

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v t e Lighthouses of Lake Ontario New York, U.S. Braddock Point Light Charlotte-Genesee Light East Charity Shoal Light Fort Niagara Light Galloo Island Light Horse Island Light Oak Orchard Light Olcott Light Oswego Harbor West Pierhead Light Rochester Harbor Light Selkirk Light Sodus Outer Light Sodus Point Light Stony Point (Henderson) Light Thirty Mile Point Light Tibbetts Point Light Ontario, Canada Burlington Canal Main Light Burlington Canal Pier Light Cobourg East Pierhead Light False Duck Island Light Gibraltar Point Light Niagara River (Front & Rear Range) Light Oakville Light Point Petre Light Port Dalhousie (Front & Rear Range) Light Port Weller Light Presquile Point Light Prince Edward Point Light Queen's Wharf Light Salmon Point Light Toronto Harbour Light Mimico Cruising Club Lighthouse