Erosion

Erosion is the process by which soil, rock, or other surface material is worn away and transported by natural forces such as water, wind, ice, and gravity. It differs from weathering, which is the breakdown of materials in place; erosion involves removal and relocation of material.

The main forms are water erosion (including sheet erosion, rill erosion, and gully erosion), wind erosion, glacial or ice erosion, and coastal erosion caused by waves and tides. The rate and pattern depend on rainfall energy, slope, soil properties, vegetation cover, and land use.

Natural factors such as rainfall intensity, storm duration, slope length and angle, and soil texture influence erosion, while human factors include deforestation, overgrazing, agriculture, urban development, mining, and poor soil conservation practices.

Impacts of erosion include reduced soil fertility and water-holding capacity, sedimentation in streams and reservoirs, alteration of landscapes, and potential damage to infrastructure. Excess sediment can affect aquatic habitats and increase flood risk by filling channels and reducing drainage capacity.

Management and assessment of erosion rely on measuring or estimating soil loss and sediment yield, with models such as the Universal Soil Loss Equation (USLE) and revised versions (RUSLE) used for planning. Prevention approaches include maintaining vegetation cover, contour farming, terracing, no-till practices, windbreaks, and sediment-control structures. In coastal areas, shoreline protection ranges from beach nourishment to seawalls and other protective measures.