![Construction of the Ste. Catherine Lock, 1958 | The Geography of Transport Systems Construction Ste Catherine Lock 1958](https://i0.wp.com/transportgeography.org/wp-content/uploads/construction_ste_catherine_lock_1958.jpg?resize=526%2C390&ssl=1)
![First Flooding of the Lower Beauharnois Lock, 1958 | The Geography of Transport Systems Flooding Lower Beauharnois Lock 1958](https://i0.wp.com/transportgeography.org/wp-content/uploads/flooding_lower_beauharnois_lock_1958.jpg?resize=532%2C418&ssl=1)
Source: Saint Lawrence Seaway Management Corporation.
The construction of locks was a difficult undertaking as in several places the rock foundation proved to be harder than expected. As the St. Lawrence Seaway was nearing completion in late 1958, locks were being flooded for the first time.