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Objects and Methods : Aggregate Distribution Canal : User Methods : Request Routing
Request Routing
Time Lag request routing is available within the Request Routing category. This category activates and deactivates the request routing calculations. If Time Lag request routing is selected, only Time Lag routing is available in the Flow Routing category on the Distribution Canal elements.
* No Routing
This method does not route requests. No restriction is placed on the flow routing methods available on the Distribution Canal elements.
There are no slots specific to this method.
* Time Lag
When the Time Lag request routing method is selected, all of the Distribution Canal elements are changed to the Time Lag routing method in the Flow Routing category.
This method routes the Delivery Requests upstream through all the Distribution Canal elements to the upstream end of the AggDistributionCanal. The method starts at the most downstream canal element and routes the Delivery Requests of that canal element and any Downstream Delivery Requests to the Routed Delivery Request slot at the top of that canal element.
Once this has been accomplished, the values in the Routed Delivery Request slot are propagated along an automatic internal link to the DS Delivery Request slot of the upstream Canal element.
When the most upstream canal element is reached, the Routed Delivery Request slot is propagated through another internal link to the Total Delivery Request slot on the AggDistributionCanal object.
Slots Specific to This Method
 Downstream Delivery Request
Type: SeriesSlot
Units: FLOW
Description: Represents the delivery request from a downstream AggDistributionCanal.
Information: Downstream Delivery Request slot is automatically linked to the DS Delivery Request slot on the last Distribution Canal element on the AggDistributionCanal.
I/O: Optional; Set to zero if not input and not linked
Total Delivery Request slot on a downstream AggDistributionCanal,
Diversion Requested slot on a WaterUser, or
Total Diversion Requested slot on an Agg Diversion Site.
 Total Delivery Request
Type: SeriesSlot
Units: FLOW
Description: sum of the Delivery Requests routed to the upstream end of the AggDistributionCanal
Information: The values in this slot are set via propagation from the Routed Delivery Request slot of the most upstream Distribution Canal element.
I/O: Output only
Method Details 
The values in the Total Delivery Request slot are calculated as follows.
    
    
The total request may also include evaporation and change in storage if those methods are active.
    
Note:  Lag Time, Delivery Request, Routed Delivery Request, (Variable) Seepage Flow Fraction, and DS Delivery Request are slots on the Distribution Canal element.
The Routed Delivery Request, calculated in the equation above, is then set for the timestep, t - Lag Integer, where t is the current timestep.
Note:  If a method is selected in the Canal Storage category, the Routed Delivery Request is always zero when the canal is draining. In other words, no downstream or delivery requests can be routed upstream when the canal is draining.
The Routed Delivery Requested value is propagated across a link to the DS Delivery Request slot on the Canal element just upstream. The process above is then repeated until Routed Delivery Request is calculated on the most upstream Canal element. The value then propagates across a link to the Total Delivery Request slot on the AggDistributionCanal object.
This method executes at the beginning of the run. Therefore, it is necessary that all delivery requests on all elements are known at the beginning of the run.
Revised: 08/02/2021