Terminology in hydrology The total flow in a stream channel is commonly referred to as:

Introduction / Context:
Hydrologic terms can overlap depending on context. Engineers must correctly interpret phrases like runoff, streamflow, and discharge when estimating water availability, designing structures, or analyzing floods.

Given Data / Assumptions:

• “Total flow in a stream” means the volumetric rate passing a cross-section.
• Steady conditions are not assumed; terminology is generic.

Concept / Approach:
Runoff represents water from precipitation and other inputs reaching the channel (surface and subsurface contributions). When measured within the channel, that volumetric rate is termed streamflow or discharge (commonly expressed in m^3/s or cumecs). In many practical contexts, these terms are used interchangeably for the total channel flow at a section.

Step-by-Step Solution:

Verification / Alternative check:
Hydrology texts define discharge/streamflow synonymously and connect runoff to measured flow at the outlet of a basin.

Why Other Options Are Wrong:
Each single term alone is not “more correct” than the others in this broad wording; they collectively represent the same concept in this context.

Common Pitfalls:
Restricting “runoff” only to surface contribution and excluding interflow/baseflow, which are routinely included in catchment runoff definitions.

Final Answer:
All of the above