0 a natural wide flow of fresh water across the land into the sea, a lake, or another river:
1 water that flows naturally through a wide channel that is surrounded by land:
Changing the course of the river would cause serious environmental damage to the whole valley.
Effluents from local factories are finding their way into the river.
We want clean rivers and lakes, where you can swim without risk to your health.
The bird fauna is dominated by plovers and passerines while waterfowl (geese, ducks, and loons) are found only in river valleys and on lakes.
Wild rivers were forced into straightened riverbeds, swamps were drained, and water levels were carefully monitored throughout the country.
The airborne and satellite imagery reveals areas of vegetational change, linear features, elevations on which sites are located, and the course of rivers and drainages.