Storm Water Pollution Prevention Plan (SWPPP) Practice Test

Which factors are known to affect erosion?

1. Time of year, wind speed, and humidity

2. Ground cover, soil type, and amount/duration of rainfall

3. Construction materials and equipment

4. Climatic conditions and vegetation type

The correct answer is: Ground cover, soil type, and amount/duration of rainfall

The selection of ground cover, soil type, and amount/duration of rainfall as factors that affect erosion is insightful because each of these elements plays a crucial role in how soil is stabilized or destabilized. Ground cover, for instance, can significantly influence erosion rates; vegetation roots help bind the soil, preventing it from being washed away by rainfall or blown away by wind. The type of soil also plays a vital role since different soil textures (like sandy or clayey soils) have varying susceptibilities to erosion. Sandy soils are more easily eroded due to their loose structure, while clay soils can maintain their form better but may become very unstable when saturated. Lastly, the amount and duration of rainfall are critical because intense and prolonged rainfall can lead to greater runoff and, thus, more erosion. Brief, heavy rains can cause flash flooding and soil loss, while long-lasting rains can saturate the soil and reduce its structural integrity, both of which contribute to higher erosion rates. In contrast, the other options, while they contain valid points regarding factors influencing the environment, do not encapsulate the direct contributors to erosion in the way that ground cover, soil type, and rainfall do. Therefore, the focused combination of these three factors in option B is