washout

Washout is a term used to describe the removal or displacement of soil, rock, or other material by flowing water. It commonly results from heavy rainfall, flooding, or surface runoff and can affect natural landscapes as well as human-made structures. Washouts can occur in riverbanks, slopes, and gullies, as well as along roads, embankments, and railway lines where water undermines foundations or drainage systems.

In geology and geomorphology, washout describes erosion of the upper soil layers or sediment as water mobilizes finer particles, creating rills or gullies and reducing soil stability and fertility. In hydrology, washout contributes to sediment transport and can alter the cross-section of channels, increase turbidity, and raise flood risk downstream. Factors that promote washout include saturated soils, steep slopes, sparse vegetation, inadequate drainage, and rapid changes in water velocity.

In civil engineering and infrastructure management, washouts threaten roads, bridges, culverts, and railway lines by eroding supports or undermining foundations. Mitigation measures include proper drainage design, erosion-control practices (such as riprap, silt fences, and vegetation), regular inspections, and timely repairs after flood events. In severe cases, authorities may close affected routes to prevent further damage or danger.

In sports and event contexts, a washout refers to the cancellation or postponement of play due to rain or poor weather, most commonly in cricket and other outdoor competitions, where there is no result.