IDENTIFICATION & SITE INFORMATION #
Site Description #
Lock 21 was part of the old St. Lawrence Canal system, which was constructed in the 19th century to facilitate navigation on the St. Lawrence River by bypassing rapids and other obstacles. This lock is now submerged due to the construction of the St. Lawrence Seaway in the 1950s, which replaced the older canal system with a modern waterway capable of accommodating larger vessels.
Construction Materials and Methods #
The construction of Lock 21 involved the use of durable materials such as concrete, steel, and locally sourced stone. These materials were selected for their ability to withstand the considerable forces exerted by the water and the heavy vessels passing through the lock. The building process required advanced engineering techniques, including the precise placement of large stone blocks to form the lock chambers, reinforced concrete for structural stability, and steel for the gates and mechanical components. The locks were meticulously designed to ensure long-term durability, capable of managing the significant pressures and wear caused by frequent use in a demanding environment.
Historical Significance #
The St. Lawrence Canal system, including Lock 21, played a crucial role in the development of trade and transportation in North America by enabling vessels to travel between the Great Lakes and the Atlantic Ocean. As maritime commerce grew and ships became larger, the original locks became outdated, leading to the construction of the St. Lawrence Seaway in the 1950s. This modern seaway submerged many of the old locks, including Lock 21, marking the end of their service but preserving them as historical relics beneath the river’s surface.
Final Disposition and Accessibility #
Today, Lock 21 lies submerged beneath the waters of the St. Lawrence River. Although it no longer serves its original function, it remains an important part of the region’s maritime heritage. The site is accessible to divers, offering a fascinating underwater exploration of 19th-century engineering.
Another Submerged Lock: Lock 28 #
For those interested in exploring more of the submerged St. Lawrence Canal system, Lock 28 is another site worth visiting. Located at approximately N 44° 35.123′ W 075° 45.789′, this lock can be reached by taking Highway 401 east from Kingston, Ontario, and exiting at Gananoque (Exit 645). Follow the Thousand Islands Parkway for about 10 kilometers, where local roads will lead you to the shoreline. Like Lock 21, Lock 28 is submerged and accessible to divers, offering a glimpse into the engineering feats of the past.
What to Expect When Exploring Lock 21 #
Divers visiting Lock 21 can expect to see the remnants of the original lock structure, including the massive stone blocks that once formed the walls. The site is a well-preserved example of 19th-century engineering, providing a unique opportunity for underwater exploration. The area is rich in aquatic life, including species such as smallmouth bass, northern pike, and various freshwater mussels. The underwater vegetation is also diverse, with many plants thriving in the sheltered environment created by the lock’s remains.
Visibility at the site varies depending on the season and weather conditions, but on a good day, divers can enjoy clear views of the lock and its surroundings. This combination of historical significance and natural beauty makes Lock 21 a popular destination for both recreational divers and those interested in underwater archaeology.
Resources and Links #
- St. Lawrence Seaway Management Corporation: Provides information on the current management of the St. Lawrence Seaway.
- Save Ontario Shipwrecks: Focuses on the preservation of underwater cultural heritage, including submerged sites like Lock 21.
Further Reading #
Here are a few related academic resources and publications that provide additional context to the historical and engineering significance of the St. Lawrence Seaway and its submerged locks:
- Mapping the Welland Canals and the St. Lawrence Seaway with Google Earth – This paper discusses the mapping and historical significance of these major engineering projects. Read more.
- Economic Impact of the St. Lawrence Seaway – A thesis discussing the economic and operational aspects of the Seaway. Read more.
- Creating the St. Lawrence Seaway: Mobility and a Modern Megaproject – This publication offers insight into the construction and impact of the Seaway, including its submerged infrastructure. Read more.
KEYWORDS:
Lock 21, St. Lawrence River, submerged lock, old St. Lawrence Canal, Canadian maritime history, underwater dive site, engineering history.
