Certified Storm Water Operator Practice Exam

What factor primarily influences soil slippage in a given area?

1. Soil texture

2. Moisture content

3. Plant diversity

4. Soil temperature

The correct answer is: Moisture content

Moisture content is the primary factor influencing soil slippage in an area because it directly affects the cohesion and frictional resistance of soil particles. When soil moisture levels increase, especially during heavy rainfall or rapid snowmelt, the added water can saturate the soil, reducing friction among particles and leading to a decrease in stability. This condition increases the likelihood of landslides or soil slippage, as the weight of the water can overshadow the gravitational forces holding the soil in place. Conversely, soil texture, while important in determining how well water is retained or drained, does not directly dictate slippage as strongly as moisture content does. Plant diversity can contribute to soil stabilization through root systems, but it is not the driving force behind slippage events. Soil temperature can influence moisture evaporation and plant growth, yet it is not a direct cause of soil slippage. Thus, moisture content stands out as the most critical factor in the assessment of soil stability and risk of slippage.