North Carolina General Contractors Practice Exam

What is the purpose of a silt fence?

1. Prevent flooding

2. Control sedimentation

3. Support construction traffic

4. Mark property boundaries

The correct answer is: Control sedimentation

A silt fence is specifically designed to control sedimentation, making it an essential tool in erosion and sediment control practices, especially in construction sites. When soil is disturbed, such as during excavation or grading, it can easily wash away into nearby water bodies, leading to pollution and degradation of aquatic ecosystems. The silt fence acts as a barrier that intercepts sediment-laden water, allowing sediment to settle out before the water can flow away, thus preventing it from entering streams, ponds, and other sensitive areas. The effectiveness of a silt fence is derived from its structure, which typically consists of a permeable fabric stretched between wooden or metal posts. This configuration not only captures sediment but also facilitates the flow of water, reducing the buildup of hydrostatic pressure behind the fence. Regular maintenance and monitoring are required to ensure the silt fence remains functional and effective in sediment control. While other choices might seem plausible in different contexts, they do not reflect the primary purpose of a silt fence. For example, preventing flooding pertains more to drainage systems, while supporting construction traffic relates to the durability and design of roadways rather than sediment control. Similarly, marking property boundaries involves fencing types that delineate ownership rather than manage environmental concerns. Thus, the emphasis on