Why were locks built on the Vistula River’s lateral delta channels?

Locks were built on the lateral delta channels of the Vistula River to separate these watercourses from the main flow, thereby rendering them navigable while ensuring controlled water levels and flows.1

These improvements were part of a broader effort initiated at the end of the 19th century to manage the river's outlet to the sea and enhance the economic productivity of the delta region. By installing locks, authorities were able to regulate the water distribution across the delta's network of canals and branches.1