Question

During a rainstorm, water is flowing down the side of a hill composed of solid bedrock. What will be the effect on the relative amounts of runoff and infiltration when the water reaches an area of unsaturated soil with a gentler slope?

1. Runoff will decrease as infiltration decreases
2. Runoff will decrease as infiltration increases
3. Runoff will increase as infiltration decreases.
4. Runoff will increase as infiltration increases.

Answer 1

1 because there’s more absorption meaning less water to runoff

Answer 2

The correct answer is 2. Runoff will decrease as infiltration increases

Step-by-step explanation:

Runoff refers to the flow of water over the surface that occurs due to the soil being saturated or surfaces that do not allow infiltration such as pavement. On the other hand, infiltration occurs as water soaks into soil or it is absorbed by it.

This means in the case presented, once the water reaches an area of unsaturated soil, it is expected infiltration increases because this soil different from solid bedrock absorbs water. At the same time, runoff or water flowing without being absorbed will decrease as water will soak into the soil due to infiltration. Thus, in this case, the runoff will decrease as infiltration increases.