Question

Precipitation that infiltrates into soils and then moves laterally through the upper soil crust to appear at the surface at some location away from the entry point is known as

• A. Surface runoff
• B. Base flow
• C. Interflow
• D. Neither surface, nor base nor interflow

Hint:

Infiltrates + moves laterally in upper horizons $\implies$ Interflow Throughflow. Direct surface flow $\implies$ Overland flow. Deep saturated flow $\implies$ Base flow.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Storm hydrograph separation identifies three primary water transmission pathways: direct surface overland flow, lateral subsurface stormflow (interflow), and deep groundwater base flow.

Step 2: Detailed Explanation:
Hydrological runoff pathways:
1. Surface Runoff (Overland flow): Water flowing over the land surface without infiltrating.
2. Interflow (Throughflow Subsurface Stormflow): Precipitation that infiltrates into the soil surface, encounters a less permeable subsoil horizon (or perched saturated zone), moves laterally downslope through upper soil layers, and quickly discharges into stream channels or reappears at the surface downslope.
3. Base Flow: Groundwater effluent discharge sustaining perennial stream dry-weather flow.

Step 3: Final Answer:
Hence, this lateral subsurface movement is known as Interflow, matching option (C).