Three canals, the Carillon, Chute-à-Blondeau, and Grenville, were constructed on the north side of the Ottawa River between 1819 and 1833. Bypassing a formidable thirteen mile (21 km) stretch of rapids known as the Long Sault, they were conceived in the years following the War of 1812. At that time, the St. Lawrence was still considered vulnerable to attack from a potentially hostile United States. The canals would make the Ottawa River a navigable alternative to the St. Lawrence as a route to Kingston.
MILITARY CANALS
The canals, together with the Rideau, which was completed in 1832, were known as 
“military canals”. The reason for this was that their primary purpose was to transport troops and supplies in the event of another war with the U.S. Like the Rideau Canal, the three Ottawa River canals, with their eleven locks, were built by the Royal Engineers and paid for by the British Government.
The Carillon Carillon, located at Carillon village (now a part of Saint-André-d’Argenteuil), was the southernmost canal on the Ottawa River. Built between 1826 and 1833, it consisted of three locks and one main canal two miles (3.2 km) long. Water was fed to the canal from the North River, a small tributary of the Ottawa. The Grenville Canal, 13 miles (21 km) up-river from Carillon, was begun in 1819 and completed in 1833. Enlarged between 1871 and 1882, it was six miles long and had seven locks.The Chute-à-Blondeau Canal, situated four miles (6.5 km) up-river from the Carillon Canal, was the smallest of the three. About a quarter of a mile (0.4 km) in length, it was cut through rock, so required no stone walls except for where the lock was installed. The canal was discarded when the new dam was built at Carillon in the nineteenth century. With the construction of the modern Hydro plant in 1963, it was submerged altogether.
TRADE ROUTE
From the outset, the Carillon, Chute-à-Blondeau, and Grenville canals, which were transferred to the Government of Canada in the 1857, served commercial purposes much more than military ones. Indeed, as the threat of war waned, and trade along the Ottawa River grew, the commercial importance of these canals became increasingly obvious. Before long, they were vital links in the trade route between Montreal, Bytown (Ottawa), and Kingston.
A LONG TRIP
A major oversight in the design of the canals was that, with their shallow draught and small locks, they could not accommodate vessels as large as those on the Rideau Canal. Thus, for many years, passengers on the larger steamers operating between Montreal and Ottawa had to disembark at Carillon, and then board stages (and later railroads) to Grenville, where they would once again disembark and board a second steamer for the final leg of the journey to Ottawa. The same was true for travelers coming in the opposite direction. These interruptions obviously made for a long trip.
IMPROVEMENTS
To accommodate both the increasing size of vessels and the rapid growth in the timber and pulpwood trade, the canals were significantly enlarged between 1873 and 1882. The improved system consisted of one dam, two canals and seven locks. The Chute-à-Blondeau Canal and its lock were rendered obsolete. Even with these improvements, however, the largest passenger steamers were still too large for the canals.
PLEASURE BOATING
The expansion of the railway network in the latter half of the nineteenth century, in particular the creation of direct routes between Montreal and Kingston and Montreal and Ottawa, began the long decline of the canals as commercial and passenger transportation routes. In time, however, with the growth in pleasure boating, these old “military canals” would take on a completely new vocation altogether – that of tourist attractions.
HYDRO DAM
Between 1959 and 1963, the construction of a new state-of-the-art dam, power station and lock at the site of the Carillon rapids, drastically raised the level of the Ottawa River behind the dam. It also flooded the old canal system. However, the new lock made it possible for boats to clear the same drop in water level that was previously achieved by the original system of three canals and eleven locks. The Carillon lock now raises boats 62 feet (19 metres) in only half an hour. The Carillon Power Station is the fifteenth largest station owned by Hydro-Québec. The lock and adjacent park are the property of Parks Canada.
NATIONAL HISTORIC SITE
Today, Parks Canada maintains a National Historic Site at the site of the Carillon Canal. Popular in summer, the site is visited annually by 20,000 pleasure boaters, who use the modern lock to travel up the Ottawa River, and 30,000 people who visit the park. Within the park are vestiges of the old canal, the remains of Lock No. 1 (1830-1833), the quartermaster’s store / toll collector’s house (1843), the superintendent’s house (1843), and the jetty of the second canal (1873-1882). Interpretive plaques and seasonal exhibits help explain the history of this fascinating site. Not far away are the Carillon Barracks (c.1830), which today house the Argenteuil Regional Museum.
The Carillon and Grenville Canals were designated National Historic Sites in 1929 by the Government of Canada. The Carillon Barracks (Argenteuil Regional Museum) were designated in 1960.
References:Hydro Québec, Carillon Power Station. Parks Canada, diverse literature.Robert Legget, Ottawa River Canals and the Defence of British North America, 1988.