The Welland Ship Canal

The Welland Canal Company was incorporated in 1824 by William Hamilton Merritt, in part to provide a regular flow of water for his mills. Construction began at Allanburg on November 30, at a point now marked as such on the west end of Bridge #11 (formerly Highway 20). It opened for a trial run on November 30, 1829 (exactly 5 years, to the day, after the 1824 sod turning). After a short ceremony at Lock One, in Port Dalhousie, the schooner Anne & Jane (also called "Annie & Jane" in some texts[citation needed]) made the first transit, upbound to Buffalo, N.Y.; with Merritt a passenger on her decks. The first canal ran from Port Dalhousie on Lake Ontario south along Twelve Mile Creek to St. Catharines. From there it took a winding route up the Niagara Escarpment through Merritton to Thorold, where it continued south via Allanburg to Port Robinson on the Welland River. Ships went east (downstream) on the Welland River to Chippawa, at the south (upper) end of the old portage road, where they would make a sharp right turn into the Niagara river, upbound towards lake Erie. Originally, the section between Allanburg and Port Robinson was to have been carried under a tunnel, however, sandy soil conditions made that unfeasible and a deep open cut was used instead.

A southern extension from Port Robinson opened in 1833. This extension followed the Welland River south to Welland (known then as the settlement of Aqueduct, for the wooden aqueduct that carried the canal over the Welland River at that point), and then split to run south to Port Colborne on Lake Erie. A feeder canal ran southwest from Welland to another point on Lake Erie, just west of Rock Point. With the opening of the extension, the canal stretched 44 km (27 mi) between the two lakes, with 40 wooden locks. The minimum lock size was 33.5 m by 6.7 m (110 ft by 22 ft), with a minimum canal depth of 2.4 m (8 ft).

In 1839 the government of Upper Canada approved the purchase of shares in the canal company in response to the company's continuing financial problems in the face of the continental financial panic of 1837. The buyout was completed in 1841, and work began to deepen the canal and to reduce the number of locks to 27, each 45.7 m (150 ft) by 8.1 m (26.5 ft). By 1848, a 2.7 m (9 ft) deep path was completed, not only through the Welland Canal but also the rest of the way to the Atlantic Ocean via the St. Lawrence Seaway.
Competition came in 1854 with the opening of the Erie and Ontario Railway, running parallel to the original portage road. In 1859, the Welland Railway opened, parallel to the canal and with the same endpoints. But this railway was affiliated with the canal, and was actually used to help transfer cargoes from the lake ships, which were too large for the small canal locks, to the other end of the canal (The remnants of this railway are today owned by the Trillium RR). Smaller ships called "canallers" also took a part of these loads. Due to this problem, it was soon apparent that the canal would have to be enlarged again.

In 1887, a new shorter alignment was completed between St. Catharines and Port Dalhousie. One of the most interesting features of this third Welland Canal, was the Merritton Tunnel on the Grand Trunk Railway line that ran under the canal at Lock 18. Another tunnel, nearby, carried the canal over a sunken section of the St David's Road. The new route had a minimum depth of 4.3 m (14 ft) with 26 stone locks, each 82.3 m (270 ft) long by 13.7 m (45 ft) wide. Even so, the canal was still too small for many boats.

Construction on the current canal began in 1913 and was completed in 1932. The route was again changed north of St. Catharines, now running directly north to Port Weller. In this configuration, there are eight locks, seven at the Niagara Escarpment and the eighth, a guard lock, at Port Colborne to adjust with the varying water depth in Lake Erie. The depth was now 7.6 m (25 ft), with locks 233.5 m (766 ft) long by 24.4 m (80 ft) wide.

In the 1950s, with the building of the present St. Lawrence Seaway, a standard depth of 8.2 m (27 ft) was adopted. The 13.4-kilometre (8.3 mile) long Welland By-pass, built between 1967 and 1972, opened for the 1973 shipping season, providing a new and shorter alignment between Port Robinson and Port Colborne and by-passing downtown Welland. All three crossings of the new alignment - one an aqueduct for the Welland River - were built as tunnels. Around the same time, the Thorold Tunnel was built at Thorold and several bridges were removed. These projects were to be tied into a proposed new canal, titled the Fifth Welland Canal, which was planned to by-pass most of the existing canal to the east and to cross the Niagara Escarpment in one large superlock. While land for the project was expropriated and the design finalized, the project never got past the initial construction stages and has since been shelved. The present (4th) canal is scheduled to be replaced by 2030, almost exactly 100 years after it first opened, and 200 years since the first full shipping season, in 1830, of the original canal.