Download presentation
1
Flood Routing & Detention Basin Design
Professor Ke-Sheng Cheng Dept. of Bioenvironmental Systems Engineering National Taiwan University
2
The storage effect The storage effect of a water-retention structure or a channel reach can change the shape of the inflow hydrograph. Therefore two types of routing procedures are needed to calculate the outflow hydrograph. Level-pool routing Channel routing
3
Level-Pool Routing (Reservoir Routing)
For a reservoir the outflow is uniquely controlled by the water depth (or stage) of the reservoir pool. Also, the reservoir storage is a single-value function of the stage. Flow velocity in the reservoir is usually very low.
4
Comparison of flow routing under invariable and variable stage-discharge relationships
Invariable S~Q relationship Variable S~Q relationship
5
Discharge under variable S~Q relationship
6
Reservoir routing Modified puls method (Storage indication method)
7
+
9
An example Given the following storage-outflow relationship and inflow hydrograph, calculate the outflow hydrograph. (Use 10-minute routing interval).
10
Stage~storage~outflow relationship
12
Reservoir routing as a computation of mass balance
For a reservoir the outflow is uniquely controlled by the water depth (or stage) of the reservoir pool. Also, the reservoir storage is a single-value function of the stage. As a result, given a stage the reservoir storage and outflow can be uniquely determined, if the stage~storage and stage~outflow relationships are known. An intuitive trial-and-error approach for reservoir routing can be implemented.
13
Alternative solution Stage~storage Stage~discharge
14
Spreadsheet calculation
15
Inflow-outflow-(10*storage)
16
Channel routing
Similar presentations
© 2018 SlidePlayer.com Inc.
All rights reserved.
Ppt on meaning and importance of communication Ppt on mars one wiki Ppt on environmental issues in chennai Ppt on agriculture and food security Ppt on electric arc furnace Ppt on various dance forms of india Ppt on series and parallel circuits examples Ppt online shopping cart system Ppt on standing order 2-99 Ppt on waves tides and ocean currents definition