rainfallerosion

Rainfallerosion is the erosion of soil and sediment resulting from the impact of raindrops and the subsequent overland flow of water. It encompasses splash erosion, sheet erosion, and the initiation of rill and gully erosion on bare or sparsely covered soils. The process begins with raindrop impact detaching soil particles; subsequent surface runoff transports detached material downslope, while infiltrating water can form sheet flow or concentrate in channels. Rainfallerosion can be rapid during intense storms and is influenced by soil saturation, crust formation, and crust break-up.

Key factors include rainfall characteristics (intensity, duration, amount, drop size), soil properties (texture, structure, porosity, infiltration rate, moisture content), surface cover (vegetation, mulch, residue), slope length and gradient, and land management (tillage, compaction, residue removal). Wet soils and bare ground are particularly vulnerable; soil crusts or sealing can either reduce infiltration or, if broken by traffic or tillage, increase runoff.

Assessment often uses sediment yield measurements, runoff plots, and rainfall erosivity indices (R-factor in erosion models such as USLE/RUSLE). Rainfallerosion contributes to soil fertility loss, sedimentation in waterways, turbidity, and downstream flood risk. It interacts with other erosion processes, including wind erosion on sandy soils and gully erosion in steeper terrain.

Mitigation measures focus on increasing infiltration and protecting the surface: maintaining vegetative cover, residue retention, mulching, contouring, terracing, windbreaks, and reduced tillage. Effective management reduces particle detachment and runoff velocity, thereby lowering soil loss during rainfall events.