Certified Storm Water Operator Practice Exam

Which property of soil affects its erodibility?

1. Color, consistency, and moisture content

2. Texture, structure, and cohesion

3. Temperature, weight, and age

4. Size, depth, and saturation level

The correct answer is: Texture, structure, and cohesion

The property of soil that most significantly affects its erodibility is its texture, structure, and cohesion. Soil texture refers to the size of the individual particles that make up the soil, such as sand, silt, and clay. Different textures alter how easily water can flow through the soil and influence the soil's ability to hold together under erosive forces. For example, sandy soils tend to have larger particles that can be easily detached and transported by wind or water, making them more prone to erosion compared to clay soils, which have finer particles that stick together more effectively. Soil structure describes how these particles are arranged and how they bind together, forming aggregates. Well-structured soils have stable aggregates that are less susceptible to erosion, while poorly structured soils can easily break apart, leading to increased erosion. Cohesion is the internal molecular attraction between soil particles. Soils with high cohesion are less likely to erode, as the particles tend to stick together. Conversely, soils with low cohesion tend to be more erodible, as they can easily be moved by water flow or wind. Together, these three properties play a crucial role in determining how resistant or vulnerable the soil is to erosive processes. In contrast, factors such as