What action is required regarding the lower edge of a silt fence during installation?

When installing a silt fence, it is important to ensure that the lower edge is properly secured to prevent sediment from bypassing the fence. The correct action is to vertically trench the area where the lower edge of the silt fence will be placed and then cover it with backfill. This method effectively anchors the silt fence into the ground, creating a barrier that helps to intercept sediment-laden water and reduces soil erosion during rainfall events.

By trenching and backfilling, the lower edge of the silt fence is embedded in the soil, making it less likely that water will flow underneath the fence and carry sediment along. This is a critical installation practice, as it ensures the fence functions effectively in controlling sediment movement and protecting water quality. The integrity of the silt fence is thus maintained, enhancing its performance throughout the duration of its use.