Erosion Control is the first line of defense against rain and water flow -- involving tarps, seeding and mulching, and other forms of soil stabilization. This is meant to prevent particle discharge from occuring in the first place. In the case of overflow, sediment control can come in the form of sandbags, silt fences, filtration, or filter socks. These are meant to catch sediment after erosion has already occured.
Erosion control is considered the most effective form of erosion and sediment control, as it stops the discharge of particles in the first place. However, in an unexpected rainstorm, some erosion controls may prove ineffective. Grass planted too late or mulch not yet laid will be caught completely bare in a sudden downpour. In some projects, it may be possible to use physical barriers to both protect bare soil from erosion, and to redirect incoming or outgoing runoff.
