Runoff and basin yield terminology – identify the incorrect statement Read each statement about runoff components and drainage-basin yield. Choose the single statement that is incorrect.

Introduction / Context:
Hydrology uses precise terminology for components of streamflow and for how catchment performance is summarized. Examinations often test whether a learner can discriminate between correct and subtly incorrect definitions.

Given Data / Assumptions:

• Standard surface-water hydrology definitions.
• Annual (or seasonal) runoff can be reported as volume or as depth over the basin.
• Base flow refers to the delayed groundwater contribution to streams.

Concept / Approach:
All four domain statements (a–d) align with accepted definitions. If each is correct, the only consistent choice for “incorrect statement” is “None of these,” meaning none of the listed statements are wrong.

Step-by-Step Solution:
Check (a): Surface runoff indeed denotes net flow reaching surface channels from precipitation excess.Check (b): Base flow is the sustained contribution from groundwater storage to streams.Check (c): Yield is frequently reported as an equivalent depth (cm or mm) over the basin.Check (d): Volume = Depth * Area is the standard conversion.Therefore, choose “None of these.”

Verification / Alternative check:
Hydrology manuals consistently define runoff depth and yield in this manner and convert to volume using basin area.

Why Other Options Are Wrong:

• Picking any of (a)–(d) would contradict textbook definitions.

Common Pitfalls:
Confusing base flow with interflow; base flow is groundwater-fed and most persistent, whereas interflow is shallower subsurface flow with shorter response time.

Final Answer:
None of these