Welland Canal Port Maitland. With the opening of the extension, the canal stretched between the two lakes, with 40 wooden locks. The minimum lock size was , with a minimum canal depth of . Deterioration of the wood used in the 40 locks and the increasing size of ships led to demand for the Second Welland Canal, which used cut stone locks, within just a few years. In 1839 the government of Upper Canada approved the purchase of shares in the private canal company in response to the company's continuing financial problems in the face of the continental financial panic of 1837.
Welland Canal first canal ran from Port Dalhousie, Ontario on Lake Ontario south along Twelve Mile Creek to St. Catharines. From there it took a winding route up the Niagara Escarpment through Merritton, Ontario to Thorold, where it continued south via Allanburg to Port Robinson, Ontario 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 made a sharp right turn into the Niagara River, upstream towards Lake Erie. Originally, the section between Allanburg and Port Robinson was planned to be carried in a subterranean tunnel.