Aerial footage 3840×2160 4K. Canals are human-made channels for water conveyance, or to service water transport vehicles. In most cases, the engineered works will have a series of dams and locks that create areas of low speed current flow. These areas are referred to as slack water levels, often just called levels. A canal is also known as a navigation when it parallels a river and shares part of its waters and drainage basin. Brown fields and giant alluvial plain. Drainage channel.