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USACE-SWD Modeling Techniques : Modeling Operations : Direct from Reach Diversions
Direct from Reach Diversions
Water is diverted directly out of the river to meet demands. This operation does not require additional rules but does require additional model setup.
Model Setup
A reach object must be added for each demand point. The reach will be set up to have a diversion and will have a Min Diversion Bypass method selected. The minimum base flow requirement will be input on the Minimum Diversion Bypass slot. The reach will be linked to a water user with the appropriate methods selected. The water user object will always divert the computed Diversion Request as long as there is sufficient water available. If not, it will take the available water. The available water is computed as the total flow in the reach (Inflow) minus the Minimum Diversion Bypass.
Make sure to also add these reach objects to the subbasins created for other operations.
Reach Methods
On the diversion reach, select the methods summarized in Table 3.4.
Table 3.4   
Section in Objects
No Routing
Local Inflow and Solution Direction
No Local Inflow, Solve Outflow
Diversion from Reach
Available Flow Based Diversion
Min Diversion Bypass
Periodic Min Bypass
Water User and/or Diversion Object Methods
Either a water user or a diversion object can be used, but typically a water user is recommended. On the water user, the method selections summarized in Table 3.5 are recommended.
Table 3.5   
Section in Objects
Return Flow
Fractional Return Flow
Fraction Return Flow Input
Input Fraction, Zero Fraction, or Periodic Fraction
Diversion and Depletion Request
Use either Input Request, Periodic Diversion Requests or Reservoir Level Lookup.The latter method allows the Diversion Request to be based on the operating level of a reservoir.
Note:  If diversion requests are based on a reservoir level, but the reservoir level is disabled because it is set to Pass Inflows, requests are set to zero. See Diversions Based on Disabled Reservoirs for details.
Revised: 01/05/2024