The Gekanaliseerde Hollandsche IJssel is a managed waterway flowing westward through the provinces of Utrecht and South Holland in the Netherlands. Originally a distributary of the Lek river, it is now fed by the Doorslag, an arm of the Merwede Canal, beginning in Nieuwegein and passing through IJsselstein, Montfoort, Oudewater, and Gouda before emptying into the Nieuwe Maas near Capelle and Krimpen aan den IJssel on the outskirts of Rotterdam. The river's banks are lined with characteristic Dutch riparian vegetation — primarily willow (Salix spp.) and alder (Alnus glutinosa) forests — that create softwood floodplain habitats periodically inundated by seasonal water fluctuations. These vegetated corridors serve as nursery habitat for aquatic species and provide excellent cover and foraging zones for fish throughout the system. A storm surge barrier at the river's mouth, constructed as part of the Delta Works, protects the waterway from tidal intrusion and helps regulate water levels upstream.