In the water cycle, infiltrometers are primarily used to evaluate the rate of which process?

Correct answer: Rate at which water enters and soaks into soil, called infiltration rate

Direct answer: B, the infiltration rate. Infiltration is the entry of water from the ground surface into soil. An infiltrometer applies or maintains water at a defined area and records how quickly the soil accepts it, often as depth of water per unit time. The measured rate depends on soil texture, structure, compaction, organic matter, surface condition, and current moisture. If rainfall or water application exceeds the infiltration capacity, excess water may remain at the surface or become runoff. A is wrong because transpiration is water loss from plant surfaces. C concerns atmospheric clouds, and D is the movement of water along a river channel; neither is measured by an infiltrometer. Memory cue: “infiltration” begins with “in”—water goes in to the soil.