Why were locks built at Volga River reservoir complexes?

Locks were built at Volga River reservoir complexes to facilitate navigation. Because the construction of large dams converted the river into a series of man-made lakes, these locks are essential for allowing rivercraft and ships to bypass the dams and continue their passage along the waterway.1

These navigation locks are a standard feature of all reservoir complexes along the Volga and its major tributary, the Kama River, ensuring that the river remains a viable transportation route despite the significant changes to its natural flow.1