The Scenario transfer node (STN) handles the joining of two scenarios and conceptually comprises of two components, the Upstream STN and Downstream STN (as shown in Figure 1). The node links two scenarios and runs them together. Constituents, orders and ownership are passed between the two scenarios. However, off allocation does not operate over scenarios, instead, the STN operates like an off allocation boundary - similar to the transfer ownership node.
The STN operates in either a connected or disconnected mode:
- In connected mode, the Upstream STN passes information such as flow and constraints to the Downstream STN, while the downstream STN passes information such as orders to the Upstream STN. This links the two scenarios together; and
- In disconnected mode, the scenarios run independently of each other. The Upstream STN acts like a minimum flow requirement node and the Downstream STN acts like an inflow node.
Figure 1. Scenario Transfer node
Adding STNs
Connecting two scenarios with an STN requires adding both an Upstream STN and a Downstream STN. Ensure both upstream and downstream scenarios are in the same project (see Importing Scenarios).
In the upstream scenario, you add the STN to an outlet of the model. In the downstream scenario, you add the STN to an inlet of the model. In a schematic scenario, you can add an STN and connect it with a straight through link to an inlet or outlet, as appropriate. In a catchment scenario you can also change the node model of an existing node at an outlet or inlet. When linked to the network, the STN node icon will automatically change to an Upstream or Downstream STN, depending on whether the connection is downstream
Configuring STNs
Connecting STNs
To connect an Upstream STN to a Downstream STN:
- Open the feature editor of one of the STNs (eg. Downstream STN) and select Scenario Transfer (Figure 2)
- Select the desired scenario as the Scenario Target from the list of all other scenarios in the project (eg. Upstream Scenario).
- Select the name of the STN that you wish to connect to as the Node Target (eg. Upstream STN)
Once you have connected an STN using its feature editor, the other STN's feature editor updates with the corresponding Scenario Target and Node Target. If you Clear the connection in either STN feature editor, it will also be deleted from the other STN.
Figure 2. Scenario Transfer Node, Connecting Scenarios
Disconnected modes
An Upstream STN
In the upstream scenario:
- Open the Upstream STN feature editor
- For connection mode, you need to connect a Downstream STN to an Upstream STN. This is done by navigating to the Scenario Transfer menu item, but requires both an Upstream STN and a Downstream STN to be available. If you have yet to create one, leave this blank. Configuring the connection between consitutents, ownership and orders is done in the downstream STN feature editor.
- In disconnected mode, this node will act as a minimum flow requirement node. If desired, configure the minimum flow requirements by navigating to Scenario Transfer » Disconnected » Minimum Flow Requirement, see Minimum Flow Requirement node.
In the downstream scenario:
- Add an STN at an inlet of the model, it will usually replace an inflow node. When connected, the STN node icon will automatically change to become a Downstream STN.
- Open the STN feature editor.
- Configure for connected mode on the Scenario Transfer menu item:
- You can configure mapping of constituents, ownership and orders
- In disconnected mode, this node will act as an inflow node. Use the STN feature editor to configure the inflow by navigating to Scenario Transfer see Inflow node.
Constituents
A model will operate even if the constituent processing methodology (lumped or marker) is different for each scenario. For example, consider the pitcher scenario is configured with lumped routing and the catcher scenario with marker routing. Constituents will be passed from the pitcher to the catcher even though the methodology is not the same.
Once constituents are defined in both the pitcher and catcher scenarios, you can map constituents between the two scenarios using the STN feature editor. Choose Connected > Constituent Mapping from the tree and click Add (as shown in Figure 2).
Figure 2. STN, Constituent mapping
Ownership
Ownership can be set up in linked scenarios using Connected > Ownership in the feature editor (as shown in Figure 3). Configuration of ownership is similar to the Transfer ownership node (when set up as a boundary node).
Figure 3. STN, Ownership
