Just like the inflow node, you can forecast flows in the Wetlands Hydraulic Connector node (Figure 3). In a rules-based ordering system, the forecast, along with the Ordering loss in Hydraulic Connector Details table (Figure 2), calculates the loss of flow to the wetland when orders are passed up through this hydraulic connector. The orders will be increased to ensure orders are satisfied further down the system.
Figure 3. Wetlands Hydraulic Connector node, Forecast
Wetland links use a hydraulic model and are used to connect storages within a wetland, or a wetland to a river. They are represented by a green line with a black arrow, and are created by using the side anchor point from a Storage node or Wetlands Hydraulic Connector node (Figure 4).
Figure 4. Wetland link, Schematic Editor
Note that a conveyance link is the type of wetland link used in Source. The discharge across the link depends on the Modified Conveyance function and the hydraulic head difference between the two ends of the link. The Modified Conveyance is dependent on the hydraulic conveyance and the channel length. The weighting configuration controls the point in the channel at which the hydraulic head difference is applied (see Wetlands SRG).
Wetland links can be either regulated or unregulated, uni- or bidirectional, and you can configure how the model calculates the water surface elevation (reduced level - RL) used to look up the modified conveyance relationship. Use the Wetland link feature editor to configure each of these parameters.
This tab (Figure 5) is used to specify the direction type of flow in the link, weighting, and the Modified Conveyance Relationship.
The Direction Type allows Wetland links to be either uni- or bidirectional. If unidirectional is chosen, flow along the link will only be in the default direction. The default flow direction is set when the modeller selects one node before the other when creating the wetland link. The flow direction is indicated by the direction of the arrow on the link in the Schematic Editor (Figure 5). When bidirectional is chosen, flow can go in both directions along the link. Flow that moves in the default direction is represented by a positive number, while flow in the other direction is represented by a negative number.
The Weighting applies to the head difference between each end of the Wetland link, and adjustments to this value are important if there is a significant head difference between the wetland and river water surface elevations. For example, if there is a Wetland link from a wetland Storage node to a Wetlands Hydraulic Connector node (as in Figure 5), and the water surface elevations of the Storage and Connector are RL1 and RL2, respectively; then a weighting of 0.5 gives a weighted water surface elevation that is the average of RL1 and RL2. If a weighting of 0 were used instead, the weighted water surface elevation is equal to RL1, and if a weighting of 1 were used, the weighted water surface elevation is equal to RL2.
The Modified Conveyance Relationship allows the user to enter the relationship between Elevation, which is the weighted water surface elevation, and the Modified Conveyance.
Figure 5. Wetland link, Configuration
This tab (Figure 6) is used to specify whether the link is regulated or not (using the Flow Regulated checkbox) and to allocate a function to the flow.
Figure 6. Wetland Link, Target flow
Ordering at wetlands
Orders for wetlands can be modelled in Source by connecting a Water User node with an in-stream demand model to a Supply Point node upstream of the wetland cluster for which the water is to be ordered, and using target flow functions on the wetland links to move the water into the wetland once it arrives.
Each storage in a wetland can have a target level or range and place orders along standard links to ensure the storage remains at the level or within the range.
Storage nodes on the boundary of a wetland cluster may also be used to supply downstream orders. The ordering system will bypass/ignore wetland links.
Viewing wetland results
In the Results Manager, select the following results to view the output of the different components of a wetland:
- Cell: Storage » Storage Level for a wetland Storage node;
- Boundary condition: Wetlands Hydraulic Connector » Average Reduced Water Level for node-related results; and
- Wetland link ('connector'): Wetland Link » Average Flow Rate