The relationship between humans and rivers, which represent freshwater environments, is complicated. Rivers serve primarily as a freshwater resource and as sinks for domestic and industrial waste water. The consequences from this usage occur from diverse activities and root themselves in complex, interdisciplinary systems and practices.
Environmental changes in rivers usually result from human development, such as population growth, the dependence on fossil resources, urbanization, global commerce and industrial and agricultural emission. Anthropogenic activities also include discrete elements like the use of fire, domestication of plants and animals, soil development, the establishment of settlements and irrigation. River ecosystems have been transformed downstream from the point of pollution. Active human transformations, river engineering, have altered the river systems and ecosystems.