2. River degradation: causes and effects

The causes of river degradation are multiple, in terms of nature, intensity and potential accumulation. They are very frequently linked to land use in the catchment area that feeds watercourses via surface or underground runoff: areas of intensive agriculture, industrial or urban development, etc. These very different types of land use modify the chemical composition of discharges, with the presence of excess nutrients and toxic substances in dissolved or particulate form (for more information, see [GE 1 014] ).

This obviously results...