Which practice is used for sediment control by filtering water?

Silt fences are specifically designed for sediment control by filtering water as it flows through. They are installed along the perimeter of a construction site or at strategic points to intercept sediment-laden runoff. The fabric of the silt fence acts as a barrier, allowing water to pass through while trapping sediment on the upstream side. This filtration process is crucial in preventing sediment from entering stormwater systems, nearby water bodies, and causing degradation to aquatic habitats.

In contrast, earth dikes are primarily used for redirecting water flow and managing drainage rather than filtration. Level spreaders help to evenly distribute runoff across a wide area to minimize erosion but do not filter sediment in the same manner as silt fences. Rock outlet protection involves using rocks to stabilize drainage outfalls and prevent erosion, but it does not serve the primary function of filtering sediment from water. Hence, silt fences remain the best practice for sediment control via water filtration.