Which factor is critical to keeping sediment from leaving a construction site?

Placing barriers like silt fences is critical to keeping sediment from leaving a construction site because these structures are designed specifically to prevent sediment-laden water from escaping into surrounding areas. Silt fences act as a sediment control measure that filters out sediment while allowing water to pass through. This is essential during rain events, where surface runoff can carry sediment off-site.

In contrast, temporary fences, while they may serve some purpose in site management, do not effectively prevent sediment discharge. Similarly, while removing excess soil can help manage site conditions, it does not directly address how sediment is controlled during wet weather. Restricting site access can help reduce unnecessary disturbance but does not provide a physical barrier to prevent sediment loss. Therefore, the use of silt fences is a proactive and effective method to manage sediment on construction sites by ensuring that sediment is contained and filtered appropriately.