During the Precambrian (4.5 to 0.54 billion years ago), magma created the intrusive granites of the Canadian Shield. During the Wisconsin glaciation 10,000 years ago, the area was covered with a 2 km thick ice sheet [1]. The land shape was carved by the advance of the ice sheet. The meltwaters left gravel, sand, clay and boulders deposited on the lake plain. At the end of the last glacial period about 14,000 years ago, the Eastern Great Lakes began to form as ice started melting and continental glaciers retreated northward [2].

About 200,000 years ago, the Lake Erie basin was an east-flowing river. This ancient drainage system was destroyed and carved out by the first major glacier [3]. The Lake Erie and Lake Ontario basins were cut by glacial ice advancing through the ancient river valley deepening and enlarging the lowlands [1]. Glaciers carved deeper on the eastern side of Lake Erie, which was soft shale. The western side of the lake was underlain by hard carbonate rocks composed of dolomite and limestone.

The predominant portion of the central Ontario Zone includes most of the prime agricultural lands in Canada (Figure 4). This zone is the fastest growing urban region of the country (Figure 5). The central Ontario Zone and subject to land use conversion from agricultural land. Ontario was initially an agrarian society as a result of the presence of most of the prime agricultural soils. Other Canadian lands, such as the Canadian Shield Zone were difficult to farm due to the shallow to bedrock soils [5]. The most successful settlements were on the

prime agricultural areas along the St. Lawrence River. These agricultural communities attracted service industries. Most of the prime agricultural land is located south of the Canadian Shield [6] and along the Lake Ontario shoreline and southwestern Ontario to the west of Lake Ontario and north of Lake Erie (Figure 5). This Canadian region also has the highest temperatures for plant growth.

Lake Ontario has both the lowest elevation (Figure 6) and is the farthest east of the Great Lakes. The Lake Ontario name was derived from an Iroquois word meaning “beautiful lake”. Since 1000 B.C. and after the last Wisconsin glaciation event, Native American tribes inhabited the Great Lakes region. The Hopewell culture was visible around 1000 A.D. [7].

In 1615, Etienne Brule, a French explorer, discovered Lake Ontario, which was first called Lake St. Louis in 1632. However, on a Sanson map in 1656, it remained Lac de St. Louis. In 1660 Creuxius gave it the name Lacus Ontairus, meaning beautiful lake. During the 17^th and early 18^th centuries, the French built forts along the south shore of Lake Ontario. The lake has rich history of trade and commerce. After the War of 1812, canals including the Erie, Champlain and Oswego canals, were built and utilized by steamships. Lake Ontario was a commerce and transportation hub until railroads were built [8].

The St. Lawrence River connects the Gulf of Saint Lawrence with Lake Ontario (Figure 3) [6]. Lake Ontario, with an 18,960 km² surface area, is the smallest of all the Great Lakes and has the lowest elevation of 74 m (Figure 6). However, Lake Ontario holds 4 times more water than Lake Erie. In 2017, the water levels of Lake Ontario reached their greatest height in the last 100 years. This resulted in severe erosion and massive flooding [5]. The St. Lawrence River provides the only natural outlet for the entire Great Lakes Basin. Lake Ontario is the eastern most Great Lake and is below the Niagara Escarpment (Figure 7) at the base

level of the falls. Niagara Falls and the Niagara Escarpment were an obstacle to navigation into the upper Great Lakes until the Trent-Severn Waterway and the Welland canals were built to permit ships, boats and barges to pass to the west of the Niagara River and across the Niagara Escarpment. Lake Erie flowed naturally into Lake Ontario via the Niagara River and later partially through the Welland Canal. The canal, located 40 km west of Niagara River, provides a navigation channel between Lake Ontario and Lake Erie. Lake Ontario is bordered by the Province of Ontario and New York State [1].

Lake Erie, named by the Erie tribe, is the 4^th largest Great Lake in terms of surface area, and has an elevation of 173.5 m (Figure 6). It is the smallest lake by volume, shallowest and southernmost. The deepest point in Lake Erie is only 64 m (Figure 6). Lake Erie’s northern shore is in the Canadian province of Ontario [1]. The southern shore is Pennsylvania, Ohio, Michigan and New York on the west end of the lake. The primary natural outlet for Lake Erie is the Niagara River which flows over Niagara Falls (Figure 7).

The Niagara River provides hydroelectric power (Figure 8) to Canada and the United States, and it spins huge turbines near Niagara Falls at Lewiston, New York and Queenstown, Ontario. The Welland Canal now provides an additional human-made outlet for Lake Erie water flowing into Lake Ontario. The Welland Canal diverts water via a series of 8 locks for ships to travel from St. Catharines on Lake Ontario to Port Colborne, Ontario with an elevation difference of 100 m (Figure 6). The Welland Canal avoids Niagara Falls and connects Lake Erie to Lake Ontario for navigation. Lake Erie has a surface area of 25,667 km². The largest towns on Lake Erie are Buffalo, Erie, Toledo and Cleveland [2].

The St. Lawrence River provides the Great Lakes an outlet to the Gulf of Saint

Lawrence and the Atlantic Ocean [6]. The Thousand Islands region (Figure 9), an archipelago of nearly 2,000 islands, lines the United States and Canadian border. Thus, the western section of the Lake Erie basin is only 7.6 m deep but rich in nutrients, including nitrogen, and fish. The rich nutrients have caused periodic algae blooms [9]. Lake Erie (Figure 6) was carved where the glacial ice was thinner and lacked carving and erosive power. There were as many as 3 glacial events in the Eastern Great Lakes basin. After the last of these glacial events between about 13,000 and 12,000 years ago, Lake Warren existed [10]. The lake was deeper than Lake Erie and had a shoreline 13 km to the south. The shorelines of these ancient lakes left behind sand ridges that were higher than the adjacent swamps and were used as pathways for aboriginal groups and later pioneers. These trails were eventually paved to become US Route 20 east of Cleveland and U.S. Route 30 west of Delphos. The sandy beach ridges and ancient sand dunes formed the Oak Region in Northwest Ohio. The sandy dry lake bed soils were not able to support trees except for oaks that formed a rare oak savanna. The environmental health of Lake Erie has deteriorated for decades; issues include industrial and urban pollution, overfishing, algae blooms [9] and eutrophication.

The 58 km Niagara River flows over Niagara Falls to Lake Ontario. The Niagara River (Figure 5) is part of the international border between New York in the United States, and Ontario in Canada. The word “Noagara” is thought to be derived from the Niagagarega people who occupied the Niagara River area, and the native Neutral Confederacy was noted on the 17^th-century French maps [7].

Niagara Falls has moved 11 km upstream during the last 12,000 years (Figure 2). The erosion of the Niagara Escarpment by the Niagara River has created a gorge down river from Niagara Falls [11]. The Niagara Falls water drops 100 m (Figure 10) and is used to generate hydroelectricity. The diversion of water to

generate electricity has reduced the erosion rate. The Sir Adam Beck Hydroelectric Power Stations, built in 1922 and 1954 on the Canadian side (Figure 8), and Robert Moses Niagara Power Plant (1961) on United States side, generate 4.4 gigawatts of electricity.

In the 17^th century, Father Louis Hennepin, a French explorer, discovered the Niagara River and two large islands, Navy Island and Grand Island (Figure 5). The Niagara River bank is home the oldest railroad in United States. An inclined wooden tramway (Figure 11) was built by John Montresor in 1764 and called

the “The Old Lewiston Incline” and the “The Cradles” [12].

The Welland Canal (Figure 12) in Ontario, Canada was built in between 1824 and 1829 and now connects Lake Ontario with Lake Erie [13]. The 43 km canal crosses the Niagara peninsula from Port Colborne to Port Weller in St. Catharines. The Welland Canal (Figure 13) was modified and expanded four times. The canal now has 8 locks (Figure 14) which enable ships to ascend and descend the Niagara Escarpment and by-pass Niagara Falls [13]. These locks accommodate ships up to 23.8 m in width and up to 225.6 m long. After a fourth iteration of a canal around the Niagara Falls (Figure 15), the Welland Canal passes about 3,000 ships that transported an average of 40,000,000 tons of cargo

a year (Figure 16) [14].

The Welland Canal was a major factor in the growth of Toronto, Ontario. The original canal and its successors allowed goods from Great Lakes ports such as Detroit, Cleveland, Milwaukee, and Chicago, as well as other heavily industrialized areas of the United States and Ontario, to be shipped to the port of Montreal or Quebec City, where they were reloaded onto ocean-going vessels for international shipping [13]. The Welland Canal competed with, and then later eclipsed, other narrower canals in the region including the Trent-Seven Waterway. The Erie Canal, which was a barge canal that linked New York City and the Atlantic

Ocean, and Buffalo, New York and Lake Erie, provided a shorter, more direct connection [14].

The southern Lake Erie terminus of the Welland Canal is 100 m higher than the northern terminus on Lake Ontario. The canal includes eight 24.4-m wide ship locks. The other seven of the locks (the “Lift” locks, Locks 1 - 7) are 233.5 m long and raise (or lower) passing ships between 13 and 15 m each. The southernmost lock, the “Guard” or “Control” lock (Lock 8), is 349.9 m in length (Figure 16). The Garden City Skyway, which passes over the canal, restricts the masts of ships to a maximum height of 35.5 m [13]. All other railroad or highway crossings of the Welland Canal (Figure 15) have either movable bridges (of the vertical lift or bascule bridge types) (Figure 17) or tunnels. The maximum permissible length of a ship in this canal is 225.5 m. It takes ships an average of eleven hours to traverse the entire length of the Welland Canal.

In 1824, the Province of Upper Canada incorporated the Welland Canal Company after a petition by nine “freeholders of the District of Niagara” [13]. Construction of the canal began at Allanburg, Ontario, near the west end of Bridge No. 11. This canal opened for a trial run on November 30, 1829. The first canal ran from Port Dalhousie, Ontario on Lake Ontario south along Twelve Mile Creek to St. Catharines. From there, the canal passed over the Niagara Escarpment through Merritton to Thorold, Ontario. Originally, the section between Allanburg and Port Robinson was planned to be carried in a tunnel. However, the sandy soil in this part of Ontario made a tunnel infeasible, and a

deep open-cut canal was created instead. Within just a few years, the 40 wood locks deteriorated [Table 1] and, along with the increasing size of ships, led to demand for the second Welland Canal [13].

In 1839, the government of Upper Canada approved the purchasing of the Welland Canal Company shares in the private canal company, in response to the private company’s continuing fiscal problems as a result of the 1837 continental financial panic [13]. The public buyout was completed in 1841, and work began to deepen the canal to 2.7 m and to reduce the number of locks to 27 [Table 1]. By 1846, a 2.7 m deep path was completed through the Welland Canal, and by 1848, that depth was extended all the way to the Atlantic Ocean.

In 1854, canal competition came with the opening of the Erie and Ontario Railway, running parallel to the original portage road. In 1859, the Welland Railway opened and ran adjacent and parallel to the canal with the same terminal points. This railway was affiliated with the canal and used to transfer cargo from the lake ships, which were too large for the canal locks, to the other end of the canal. Canallers, smaller ships, were also used to transfer cargo [12]. Consequently these locks were too small and soon had to be replaced. By 1871, the St. Lawrence River locks and canals allowed the transit of vessels 57 m long, 13.6 m wide and 2.7 m deep to enter Lake Erie from Lake Ontario. The St. Lawrence River locks were was enlarged 3 times to an eventual size of 233 m long, 24 m wide and 9.1 m deep.

In 1887, a shorter alignment was completed from St. Catharines to Port Dalhousie (Figure 5). An enhanced feature of the third Welland Canal was the Merritton Tunnel (Figure 18), built in 1876 on the Grand Trunk Railway line, and went under the Welland canal between Locks 18 and 19. Another tunnel carried the canal over an underground section (Figure 19) of St. David’s Road [14]. The route had a minimum depth of 4.3 m with twenty-six 82.3 m long by 13.7 m wide locks. The new locks were still too small for many ocean going ships.

Construction on the fourth Welland Canal (Figure 16) began in 1913, but work was delayed from 1916 to 1919 due to a shortage of men and workers during World War I. The canal was finally completed and opened on August 6, 1932 [14]. Dredging to the planned 7.6 m depth was not achieved until 1935. The route was re-aligned north of St. Catharines, and now ran north to Port Weller. The current configuration of the Welland Canal has eight locks, seven at the Niagara Escarpment and the eighth one, a guard lock, at Port Colborne capable of adjusting to the varying water depths of Lake Erie. The canal depth was 7.6 m and had 233.5 m long by 24.4 m wide locks. This canal name was officially changed to the Welland Ship Canal. The Welland Ship Canal’s “hands-free” vacuum mooring was installed locks 1 through 7 by 2017 [14].

A standard canal depth of 8.2 m [Table 1] was adopted in the 1950s with the creation of the St. Lawrence Seaway. The 13.4-km Welland By-Pass was built between 1967 and 1972 (Figure 5), and opened for the 1973 shipping season. The by-pass provided a shorter re-alignment between Port Robinson and Port Colborne, and went around downtown Welland. All three crossings of the new alignment were built as tunnels (Figure 19) and was an aqueduct for the Welland River. At the same time, several bridges were removed and the Thorold Tunnel was built at Thorold (Figure 20).

A Fifth Welland Canal is being planned to the east of the existing canal and

would have crossed the Niagara Escarpment in one ‘super lock’. While the design was finalized and the land expropriated, the project never advanced past the initial construction stages before being abandoned. The present Welland Ship Canal was originally designed to only last until 2030, or for 200 years after the 1830 first full shipping season. Subsequent improvements to the canal infrastructure appear to have extended the project life [13].

The Welland Canal closes in winter (January–March) when ice or weather conditions become a hazard to navigation. The shipping season reopens in spring when the waters are once again safer for navigation [14]. The historic canal facts are shown in Table 1.

The St. Lawrence Seaway connects all 5 Great Lakes (Figure 21) to the St. Lawrence River, Gulf of Saint Lawrence and Atlantic Ocean. The seaway was completed with the New York State (Erie Canal) canal [8] for cargo. The NYS Barge Canal and the St. Lawrence Seaway (Lake Ontario) were linked by the Oswego canal at the mouth of the Oswego River on Lake Ontario (Figure 22). The New York State Canal (NYS) System, originally named the New York State Barge Canal, was an 845 km canal system that included the Erie Canal and connected the Hudson River and Niagara River north of Lake Erie. Other NYS System canals included the Oswego Canal that connected the Erie Canal to Lake Ontario (Figure 22), the Cayuga-Seneca Canal that connected Seneca Lake and Cayuga Lake to the Erie Canal, and the Champlain Canal which links the Hudson River to Lake Champlain. On October, 25, 1825 the Erie Canal opened, linking Great Lakes and the Atlantic Ocean.

The Erie Canal in New York State originally ran 580 km from Albany, NY on the Hudson River to Niagara River and Lake Erie at Buffalo, New York [14]. It resulted in a completely navigable waterway route from New York City (Atlantic Ocean) to the Great Lakes. At this point in history, there were no steamships or railways through this region, and water was the least expensive way to ship bulk goods and huge tonnages as pack animals were limited to 100 kg loads. Over time, the St. Lawrence Seaway has transitioned to handle the bulk of the shipping, while the New York State (Erie) canal is now being used primarily by private recreational boaters. Only the Hudson River to Lake Champlain canal has

seen an increase in commercial use.