Certified Storm Water Operator Practice Exam

The ____________ of erosion defines the difference between rills and gullies.

1. Width

2. Depth

3. Length

4. Size

The correct answer is: Depth

The distinction between rills and gullies is primarily based on depth. Rills are shallow channels that develop on the surface of the soil due to water movement, typically forming as a result of minor erosion processes. They usually have a depth of less than 30 centimeters (about 12 inches). On the other hand, gullies are deeper and wider in comparison, with depths that generally exceed 30 centimeters, indicating a more advanced stage of erosion. Understanding this concept is crucial for stormwater management and erosion control practices, as it helps in identifying the severity of erosion and determining the appropriate measures for prevention and mitigation. Recognizing the depth difference allows operators to assess the potential impact of water flow and implement strategies to manage runoff effectively.