Grenville, Quebec

The Grenville Canal, the Chute-à-Blondeau Canal, and the Carillon Canal were built to navigate the Long Sault Rapids on the Ottawa River which stretched for 21 kilometers (13 mi) from Carillon to Grenville. The impetus for these canals was the War of 1812. During this war, attacks along the Saint Lawrence River jeopardized the communication lines between Kingston and Montreal, the two main military positions of Upper and Lower Canada. The Ottawa River Canal and the Rideau Canal were thus designed as an alternative military supply route in the event of war with the Americans.[7][8]

Grenville Canal

Work on the canal began in 1818 with the construction of a storage warehouse. In 1819 Captain Henry Vernet of the Royal Engineers arrived from Britain to lead the construction of the project. Hundreds of Irish immigrants and French Canadians were used to excavate the canal under the direction of a hundred British soldiers. In 1833 the Grenville Canal was completed with an original length of 9.5 kilometers (5.9 mi) and the entire network on the Ottawa River, including the 11 locks, was not fully completed until about 1843.[9]

The military requirements decided all aspects of the canal. The size of the locks were set to 134 feet (41 m) long, 33 feet (10 m) wide, and only 5 feet (1.5 m) deep at the thresholds. These dimensions, standards adopted for military use, were insufficient for any commercial use.[9] Forestry had become the main economic activity in this region, and from 1867, local business people demanded that the government carry out improvements to the network because the original canal network had become outdated. In 1870 the Canals Commission recommended making the Ottawa River deeper between Lachine and Ottawa. Therefore, between 1873 and 1882, the Grenville and Carillon Canals were enlarged (the dam built upstream from the village of Carillon raised the level of the Ottawa River at Chute-à-Blondeau, making the need for a lock there no longer necessary).[7]

Further changes were made from 1959 to 1963 with the construction of the Carillon hydroelectric dam and a modern 20 meters (66 ft) high lock at Carillon. This work substantially and irreversibly changed the canal network. The dam raised the water level by over 62 feet (19 m) at Carillon and over 9 feet (2.7 m) at Grenville. The new water level flooded Greece's Point and its surroundings several feet underwater and inundated the rapids of Long-Sault, transforming them into calm water.[9] Shortly afterwards, the steel swing bridge and canal locks were dismantled.[5]