How did glaciations influence the Vistula River’s present course?

The evolution of the Vistula River’s course in the lowlands was significantly shaped by successive glaciations. During the interglacial periods, the river abandoned its previous west–east valley and established its current northward path toward the Baltic Sea. The terminal section of the lower Vistula was finally stabilized in postglacial times following the formation of the Baltic Sea.1

Additionally, the general landscape of the region reflects these geological shifts; the North European Plain’s northwesterly slant, influenced by glacial history, contributed to the river's asymmetric drainage basin by allowing more powerful Baltic-area rivers to intercept glacial streams flowing farther east. Ancient glacial valleys also remain a feature of the landscape, such as the path utilized by the 19th-century Bydgoszcz Canal, which connects the Vistula with the Oder River.12