flood routing Flashcards
is the flood hydrographic a wave?
yes
what does the stage discharge relationship represent
the passage of waves.
As waves move down river, what modifies their shape?
- Channel storage
- Resistance
- Lateral addition/withdrawal
When the flood passes through a
reservoir….
- The peak is attenuated (reduced in force)
- Time base is enlarged (due to effect of storage)
What is the main purpose of reservoir flood routing?
To safely dispose the flood magnitude by REDUCING THE PEAK and INCREASING THE BASE TIME.
why do most reservoirs have spillways?
To slowly lower levels in prep for the next storm; slow enough not to flood the downstream valley.
river routing
Rivers store water on their floodplains. As the area is much larger than the channel, floodplain velocities are much lower than channel flows.
Building on floodplains increases the risk of flood hazards.
Wave Translation - Simple translation
The flood wave moves without changing its shape. Dominant in steep, straight streams.
Flow velocities are high and relatively constant.
Wave Translation - Combination
Most natural rivers have both simple translation and attenuation.
Wave Translation - Attenuation
The wave is attenuated by storage within the channel and the valley floor.
A reservoir is a good example.
What is the weighting factor value (x) in a perfectly smooth channel?
0.5
