Continuity
What goes in must come out.
Learning Goals
- Know that continuity describes equal discharge entering and leaving a reach (or cross section) of a river.
- Be able to use the concept of continuity
The concept
Continuity is a state of balance in which everything entering a cross-section must also leave that cross section. Water practically always moves through rivers much more rapidly than flood pulses cause that water to rise or fall. Therefore, we can use this assumption to connect discharge of water (or sediment) from one reach of river to another.
Videos
Potomac bedrock constriction
Watch this video of the Potomac River. I do not (yet!) expect you to know what a “hydraulic jump” is, but think about how the consriction in the river is impacting the flow. And then think about what how the speed and depth of the water might change if the flow exits the gorge into a wider area.
Continuity in a rectangular channel
You can use the concept of continuity to help solve problems by linking discharge in one cross section to that in another.
Notes
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