240386266 displays the Hydraulic Structure Boundary Conditions form. In this form the user can create or edit hydraulic structures boundary group, assign the appropriate HS equations, as well as defining a flow series for the structure. A model will typically be configured to use grid masks to prevent flow except where the hydraulic structure is located, with the structure allowing flow across the mask.
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Figure 1. Hydraulic Structure Boundary Conditions form.
In Boundary Condition Group frame, the user can enter the Group Name, or select from drop-down menus the appropriate Flow Control Type, Time Control and Flow Multiplier
In the Flow Control Type drop-down menu there a range of options based on rating curves or equations. In the case of the sluice gate, combinations of these to support rule-based and time variable control of the gate. Hydraulic structure flow options currently comprise:
- Upstream Elevation Whole Channel Rating
- Upstream Depth
- Elevation Difference
- Elevation Difference with Flow Accelerations
- US and DS Elevations
- Upstream Depth with Low Chord
- Elevation Difference with Low Chord
- Equation: Culvert
- Equation: Sluice Gate
- Equation: Weir
The details of how to configure and use the equation-based structures and flow table based hydraulic structures are described in the Flow Derived Hydraulic Structures section.
The Time Control drop-down menu is only enabled when the sluice gate option in Flow Control Type is selected. The options available in this menu are as summarized in the table below
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Name
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Meaning
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Uncontrolled Structure
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The hydraulic structure is uncontrollable type. The previous method of flow computational using lookup table or equation will be used
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Controlled using Time-Series
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The operation of the hydraulic structure is controlled using a time-series which defines the changes with time of gate openings or rating curves
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Controlled based on Upstream Elevation
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The operation of the hydraulic structure is controlled using control rules defined based on water surface elevation at an upstream location. This location can be different from the upstream cell of the structure.
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Controlled based on Head Difference
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The operation of the hydraulic structure is controlled using control rules defined based on the difference of water surface elevations at two locations upstream and downstream of the structure. These locations can be different from the upstream and downstream cells of the structure.
The user can also sets boundary Flow Multiplier options in the Boundary Condition Group frame. The drop-down menu allows selection from the following equations for the boundary flow multiplier, where q(h) are unit discharges and need to be multiplied by a dimension:
The user may also input the cell downstream from hydraulic structure in the Downstream I and J boxes. The length "L", bottom elevation and initial depth are all displayed for the downstream cell.
In the Rating Table/Flow Lookup Table frame shown in Figure 1 allows the user to set the head for each table. After the user has selected the table number, the All button applies the current flow table setting for cells in the current group. The user may also enter an Head Offset which will apply an offset to the result as described in the Head Lookup Table Equations frame. A navigation lock is a structure in a waterway designed to create a safe passage for navigation between two water pools at different levels.
EEMS provides the option of setting a navigation lock, and the option is set by clicking the Boundary Conditions item in the menu in the Model Control form and RCM on Hydraulic Structure and select New Boundary Group. The Add BC Group form will then be displayed. The user can set the Boundary Group Name as desired (Figure 1).
Figure 1. New Boundary Group
The Hydraulic Structure Boundary Conditions will be presented and contain several requirements for configuring the navigation lock. These requirements include Boundary Group Conditions, Current Boundary Cell, Time-Variable Hydraulic Structure Control, and Navigation Lock Filling/Draining Options (Figure 2). Each of these pieces of information is described below.
Boundary Group Conditions
In the Boundary Group Conditions menu, the user can change the Group Name. In the Flow Control Type menu, select the Navigation Lock option. The Use Default Masks to Control U/D Flow function should be enabled as the default (Figure 2).
Figure 2. Navigation Lock setting form
Current Boundary Cell
In the Current Boundary Cell, the user can see in the Number of Cells text box. This represents the total number of cells they have set for one gate of the navigation lock. This number depends on the actual navigation lock gate width. The user can add or remove cells as required.
In the Upstream (outflow) Cell and Downstream Cell, input the necessary information for L, I, J, Bottom, Depth, Initial WSEL, and Vertical Offset. An example configuration is shown in Figure 3. L, I, and J can be extracted from the 2DH View function. The cell bottom elevation can also be obtained from the 2DH View after you have set the bottom elevation for the model. The user should also set the initial WSEL correctly. The Depth will be automatically calculated, which is equal to the initial WSEL minus the bottom elevation.
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Figure 3. The Upstream (outflow) Cell and Downstream Cell
Time-Variable Hydraulic Structure Control
In the Time-Variable Hydraulic Structure Control section, click Edit. The Boundary Data Series will be displayed. Click Add New and input the necessary information, including Time (days), Opening Height (m), Opening Width (m), and Sill level change (m) as shown in Figure 4. Time (days) is the period for simulation. Opening Height and Width refer to the vertical and horizontal dimensions of the opening, respectively. Typically, these are observed values.
Figure 4. Boundary Data Series