Stream discharge is:

A. the area of land that drains water to a stream gauge

B. the volume of water exiting a watershed

C. the height of the water surface above a reference elevation

D. the volume of flow passing a specified point in a given amount of time



Answer :

To determine the correct answer for what stream discharge is, we need to understand the definitions and concepts related to this term. Let's analyze each given option in detail:

1. The area of land that drains water to a stream gage:
- This definition refers to the drainage basin or watershed area. This is the land area where precipitation collects and drains off into a common outlet, like a stream gage. This is not the correct definition of stream discharge.

2. The volume of water exiting a watershed:
- This description is close but not entirely accurate. While stream discharge does involve the volume of water, it is specific to the flow at a particular point in time rather than the total volume exiting an entire watershed.

3. The height of the water surface above a reference elevation:
- This definition pertains to stage or gage height, which is the elevation of the water surface above a chosen reference point, usually concerning stream flow monitoring. This is not the definition of stream discharge.

4. The volume of flow passing a specified point in a given amount of time:
- This accurately describes stream discharge. Stream discharge is the volume of water moving through a cross-section of the stream in a specified time period, typically expressed in cubic feet per second (cfs) or cubic meters per second (cms).

Based on the analysis above, the correct answer is:

◇ the volume of flow passing a specified point in a given amount of time.

To summarize, stream discharge is the measurement of the volume of water passing a certain point in the stream over a defined time period. This measurement is crucial in hydrology for understanding the dynamics and health of water bodies.