Runoff from land includes materials transported by surface and subsurface (including through infrastructure) runoff. We consider materials that originate from both point and diffuse sources, including watersheds and atmospheric sources.
Nutrient enrichment of aquatic ecosystems stimulates biological activity and has undesirable effects including algal blooms and oxygen depletion. Cultural eutrophication, or nutrient enrichment caused by human activities, is the most common water quality impairment of lakes, rivers, and coastal waters in the U.S.
The nonpoint pollution category includes four stressors.