Siltung

Siltung, or silting, is the process by which fine sediment accumulates in bodies of water, gradually reducing depth and altering flow characteristics. It commonly affects rivers, reservoirs, harbors, estuaries, and wetlands, with consequences for water quality, habitat structure, and hydraulic infrastructure.

Sedimentation results when suspended sediments settle out as water velocity decreases, or when sediment loads overwhelm natural transport capacity. Natural factors include climate, vegetation cover, and geology, while human activities such as deforestation, agriculture, mining, construction, and dam construction greatly increase erosion and deposition.

Impacts of siltation include reduced water storage in reservoirs, restricted navigation, clogged intakes for drinking water and power generation, and increased dredging costs. Ecologically, it can smother benthic habitats, alter turbidity and light penetration, shift species composition, and cause oxygen depletion in stratified or stagnating waters.

Assessment relies on bathymetric surveys, sediment cores, and long-term monitoring of turbidity, sedimentation rates, and land-use changes. Predictive models help estimate future deposition under different watershed management scenarios and dam operations.

Mitigation emphasizes watershed management to reduce erosion, such as reforestation, cover crops, terracing, and riparian buffers. In engineered settings, strategies include sediment bypass, improved sluicing and flushing, dredging with proper disposal, and sediment-transport-aware reservoir design.