Storage areas define the elements (i.e., reservoirs, lakes, detention ponds, storage nodes, etc.) where there are one or more inflows and only one computed outflow. Inflow comes from other elements in the model, such as drainage basins, routing reaches, or diversions. If there is more than one inflow, all inflow is added together before computing the outflow. It is assumed that the water surface in the storage area pool is level.
2D flow areas are regions of a model where the flow through that particular region will be computed with the HEC-RAS two-dimensional flow computation algorithms. 2D flow areas are defined by laying out a polygon representing the outer boundary of the 2D flow area and then specifying the computational mesh.
In GeoHECRAS, SA/2D connections are used to link two storage areas together with a hydraulic structure or two 2D flow areas, or a storage area to a 2D flow area. The user can draw SA/2D connections interactively on the map view or assign the already imported GIS shapefiles as SA/2D connections. The software also allows the user to place a hydraulic structure in the middle of a 2D flow area to control how flow travels from one series of cells to another series of cells. SA/2D connections can consist of a weir and gated spillway, culverts, a bridge, just a weir, rating curves, or a linear routing option. To learn how to draw SA/2D connections, refer to this article in our knowledge base.
To establish a hydraulic connection between two storage areas, 2D flow areas, or inside a 2D flow area, the SA/2D Connection Data dialog box will be used.
Follow the steps below to use the SA/2D Connection Data command:
- From the Input ribbon menu, click the SA/2D Connections dropdown menu and select the SA/2D Connection Data command.
- The SA/2D Connection Data dialog box will be displayed.
The following sections describe how to use the SA/2D Connection Data command and interact with the above dialog box.
Selecting SA/2D Connection
The Select SA/2D Connection section allows the user to select the SA/2D connection for which SA/2D connection data will be defined. In this section, the user can create, delete, and copy existing SA/2D connection data to a new SA/2D connection. In addition, the user can navigate between SA/2D connections and enter a description for each SA/2D connection.
The following entries are provided in this section:
- SA/2D connection ID
This dropdown combo box lists all the SA/2D connections that are defined in the current scenario. Click on the edit option (i.e., the pencil icon) to edit the SA/2D connection ID. The user can navigate between the available SA/2D connections using the Up and Down arrow buttons. Alternatively, the user can click the […] button to select the SA/2D connection from the Map View. Note that the Up and Down arrow buttons will be disabled (i.e., grayed out) if the current scenario contains only one SA/2D connection.
- Description
This entry field allows the user to enter additional information that describes the selected SA/2D connection.
- New
The [New] button allows the user to create a new SA/2D connection. Note that the SA/2D connection name should be unique. Otherwise, a warning dialog box is displayed, and the user is then returned to the SA/2D connection ID field to change the ID.
- Copy
The [Copy] button allows the user to copy existing SA/2D connection data along with its associated data to a new SA/2D connection. When this command is executed, the software automatically provides a unique default name for the copied SA/2D connection. The cursor is then placed into the SA/2D connection ID dropdown combo box. The user can go with the default name or enter a different ID before moving on to add any other data.
- Delete
The [Delete] button allows the user to delete the selected SA/2D connection from the current scenario.
- Less/More
The [< Less] and [More >] buttons at the Select SA/2D Connection header allow the user to expand or collapse the SA/2D Connection Plot section.
- Convert to Breakline
Clicking the [Convert to Breakline] button causes the software to convert the selected SA/2D connection into a breakline.
SA/2D Connection Specifications
The SA/2D Connection Specifications dropdown combo box contains several data panel entries that allow the user to define SA/2D connection data. The following data panel entries are listed in the dropdown combo box:
- Connection Data
- Overflow Weir
- Culverts
- Gates
- Outlet Rating Curve
- Outlet Time Series
- Dam Breach
- Linear Routing
- Geometry Adjustment
- Geometry Point Reduction.
Connection Data
This panel allows the user to define connection details for the selected SA/2D connection. By default, the Connection Data panel is shown when the SA/2D Connection Data command is selected.
Connection Details
This section is used to define the connection details for the selected SA/2D connection.
Note that if the structure is drawn between two storage areas, a storage area and a 2D flow area, or between two 2D flow areas, the user will need to define the From and To locations. If the structure is drawn completely inside of a single 2D flow area, then the To and From connections are automatically set to the 2D area.
The following entries are provided:
- From SA/2D area ID
This dropdown combo box allows the user to select the storage area or 2D flow area ID that the water flows from. Alternatively, the user can click the [Pick] button to select the storage area or 2D flow area from the Map View.
- To SA/2D area ID
This dropdown combo box allows the user to select the storage area or 2D flow area ID that the water flows to. Alternatively, the user can click the [Pick] button to select the storage area or 2D flow area from the Map View.
Clicking the [Reverse Connection] button causes the software to reverse the SA/2D connection selected in the From SA/2D area ID and the To SA/2D area ID dropdown combo boxes. When the user clicks this button, a confirmation dialog box is displayed as shown below.
Clicking the [Reverse Direction] button causes the software to reverse the geometry of the SA/2D connection. Note that this button is disabled (i.e., grayed out) if the storage area or 2D flow area is not selected. When the user clicks this button, a confirmation dialog box is displayed as shown below.
2D Weir Polyline Cell Spacing
This section is used to define the cell spacing values along the storage area or 2D flow area connection polyline. The following entries are provided:
- Cell spacing along weir polyline
This entry field represents the cell spacing along the storage area or 2D flow area connection polyline. If this entry field is left blank, then the cell spacing used in the vicinity of the storage area or 2D flow area connection will be used. Click the […] button to measure the SA/2D connection cell spacing from the Map View. - Relaxed cell spacing in 2D flow area
This entry field represents the cell spacing further away from the storage area or 2D flow area connection polyline. This value should not be the same as the Cell spacing along weir polyline value, or many cell errors may be introduced along the polyline. Click the […] button to measure the SA/2D connection cell spacing from the Map View.
Connection Structure
This dropdown combo box allows the user to select the type of routing for the selected SA/2D connection. The following options are provided:
- Structure type
This dropdown combo box allows the user to select the type of routing for the selected SA/2D connection from the following options:- Structure Routing: This option is used for both storage area and 2D flow area structures.
- Linear Routing: This option is used for storage area structures only.
Based on the type of routing selected by the user, the other data panels in the SA/2D Connection Specifications dropdown combo box get enabled or disabled.
Culvert Flow Direction
This section is used to control the culvert flow direction for all culverts defined for the selected SA/2D connection. The following entry is provided:
- All culverts
This dropdown combo box allows the user to select the culvert flow direction. The following options are provided:- No Flap Gates: This means that flow can move in both directions through the culverts. By default, this option is selected.
- No Negative Flow: This means that flow can only move in the positive flow direction through the culverts (Downstream).
- No Positive Flow: This means that flow can only move in the negative direction through the culverts (upstream).
Weir Only Computations
This section is used to define the computational method for the selected SA/2D connection. Note that this dropdown combo box is only available for the weir structure type. For other structure types, it is disabled (i.e., grayed out). The following entry is provided:
- Computation type
This dropdown combo box allows the user to define the weir computational method. The following options are provided:- At Each Time Step
- As Curves (faster)
2D Flow Area Internal Overflow Computation
This section is used to define the computational method for the flow going over the top of the structure to be computed for the selected SA/2D connection. The following entry is provided:
- Computation type
This dropdown combo box allows the user to select the overflow computational method. The following options are provided:- Weir Equation: If this option is chosen, all flow over the top of the hydraulic structure is computed with the weir equation. By default, this option is selected.
- 2D Computation (No Gates/Culverts): If this option is chosen, the flow over the top of the structure is computed as normal 2D flow between cells.
Overflow Weir
This panel allows the user to define overflow weir geometry specifications for the selected SA/2D connection.
Overflow Weir Crest Geometry
This section provides a table for entering and editing the storage area or 2D flow area connection overflow weir geometry. The geometry of the overflow weir is entered from the left to right station, looking in a downstream direction. The user enters stations and elevations at the top of the overflow weir. Everything below the defined crest geometry elevations is considered solid ground.
The right-click context menu of the table displays the commands to cut, copy, and paste data to and from the Windows clipboard as well as insert and delete rows to and from the table. In addition, the user can also export the table data to Excel or PDF format and delete the table data.
Overflow Weir Specifications
This section is used to define the dimensions of the overflow weir. The following entries are provided:
- Structure width (parallel to flow)
This entry field is used to specify the width of the overflow weir structure (measured along the flow direction). By default, the software uses a value of 10 ft. Alternatively, click the [Pick] button to measure the structure width from the Map View. - Overflow weir crest shape
This dropdown combo box allows the user to define the spillway shape at the overflow weir. This is used to reduce the weir flow coefficient due to the effect of weir flow submergence. Weir flow submergence occurs when the tailwater begins to drown out the weir flow. Two options are available: Broad Crested and Ogee.
If the user has selected the Ogee as overflow weir crest shape, two additional parameters: Spillway approach height and Design energy head are displayed in the Overflow Weir Specifications section.
- Spillway approach height
This entry field is used to define the height, which is equal to the elevation of the spillway crest minus the mean elevation of the ground just upstream of the spillway. - Design energy head
This entry field is used to define the height, which is equal to the energy grade line elevation minus the elevation of the spillway crest. - Weir coefficient
This entry field allows the user to specify the coefficient of discharge for use in the weir flow equation for overflow. Note that different coefficients are used depending on units, such as US Units or Metric (SI) Units. By default, the software uses a value of 2.6. Clicking the […] button will display a lookup dialog box containing weir coefficients.
Note that if the Ogee shaped weir is selected, the user can compute the weir coefficient based on the approach and design energy head with a click of the [Compute] button.
Culverts
This panel allows the user to define culvert specifications for the selected SA/2D connection. Note that the contents of this panel are the same as the Culverts panel contained in the Bridge & Culvert Data dialog box, except that the Distance to Upstream Cross Section field is not available in the Culvert Dimensions section. Refer to this article in our knowledge base to learn how to define culvert data using the Culverts panel.
Gates
This panel allows the user to define gate specifications for the selected SA/2D connection.
Gate Definition
This section is used to define the gates within an SA/2D connection, such as at a roadway crossing, spillway, or other flow control structure.
- Gate group ID
This dropdown combo box allows the user to select the gate group defined in the current scenario. Click on the edit option (i.e., the pencil icon) to edit the gate group ID.
- Type
This dropdown combo box allows the user to select the type of gate. The following options are available:
- Sluice
- Radial
- Overflow (Closed Top)
- Overflow (Open Air)
- User Defined Curves
Based on the gate type selected, the contents of this panel will be changed to show the required information for that gate type.
The user can also use the buttons provided in this section to add, copy, or delete the gate group(s).
Clicking the [Add] button allows the user to create a new gate group. Every newly created gate group is automatically assigned a unique ID, which can be edited.
Clicking the [Copy] button allows the user to create a copy of the selected gate group. The software automatically provides a unique ID to the copied gate group.
Clicking the [Delete] button allows the user to delete the selected gate group.
Clicking the [Delete All] button allows the user to delete all defined gate groups.
Gate Centerline Stationing
This section provides a table for defining the centerline stationing of the gate openings. The user can manually enter a different centerline stationing for each gate opening in the current gate group. Alternatively, the user can click the […] pick buttons under the Horizontal Station column to select the centerline station from the Map View or the SA/2D connection plot. Clicking the […] pick buttons under the Opening Alignment column allows the user to select the gate opening centerline alignment polyline from the Map View or draw the gate opening centerline alignment on the Map View. All gate openings within the same gate group are identical in every way, except for the centerline stationing. As new centerline stationing values are added, the number of identical gates in the group automatically increases and is reflected in the table. Note that a maximum of 25 gate openings can be defined in the table.
Gate Dimensions
This section sets the dimensions of the gate group being defined.
The following entries are provided:
- Height
This entry field is used to specify the maximum possible height that the gate can be opened. Alternatively, click the [Pick] button to measure gate height from the SA/2D connection plot.
- Width
This entry field is used to specify the width of the gate. Alternatively, click the [Pick] button to measure gate width from the SA/2D connection plot.
- Invert elevation
This entry field is used to specify the elevation of the gate invert. For overflow gates, this is the lowest elevation that the gate will open to. Alternatively, click the [Pick] button to select gate invert elevation from the SA/2D connection plot.
Sluice Gate Flow
This section is used to define the flow coefficients for the gate group being defined. Note that this section is only available when the user has selected Sluice and Overflow (Closed Top) gate type in the Type dropdown combo box of the Gate Definition section.
The following entries are provided:
- Headwater reference
This dropdown combo box is used to select the reference point from which the upstream energy head will be computed. The following options are provided:
- Sill (Invert): This option is normally used when the flow through the gate goes out into a channel. By default, this option is selected.
- Center of Opening: This option is used if the gate causes the flow to jet out freely into the atmosphere.
- Sluice discharge coefficient
This entry field is used to enter the discharge coefficient for a sluice gate opening. The discharge coefficient typically ranges from 0.5 to 0.7, depending on gate geometry and flow conditions. Clicking the […] button will display a lookup dialog box for gate coefficient assistance.
- Submerged orifice coefficient
This entry field is used to enter an orifice coefficient, which will be used for the gate opening when the gate becomes more than 80 percent submerged. Between 67 percent and 80 percent submerged, the software uses a transition between the fully submerged orifice equation and the free flow gate equations. When the flow is less than 67 percent submerged, the software uses the free flow gate equations. Clicking the […] button will display a lookup dialog box containing orifice discharge coefficients
- Headwater reference
This dropdown option is used to select the reference point from which the upstream energy head will be computed. Two available options are: Sill (Invert) and Center of Opening.- Sill (Invert): This option is normally used when the flow through the gate goes out into a channel. By default, this option is selected.
- Center of Opening: This option is used if the gate causes the flow to jet out freely into the atmosphere.
- Discharge coefficient
This entry field is used to enter the coefficient of discharge for the gate opening. This coefficient ranges from 0.6 to 0.8 for Radial gates and 0.5 to 0.7 for Sluice gates.
- Submerged orifice coefficient
This entry field is used to enter an orifice coefficient, which will be used for the gate opening when the gate becomes more than 80 percent submerged. Between 67 percent and 80 percent submerged, the software uses a transition between the fully submerged orifice equation and the free flow gate equations. When the flow is less than 67 percent submerged, the software uses the free flow gate equations.
Radial Gate Flow
This section is used to define the flow coefficients for the gate group being defined. Note that this section is only available when the user has selected Radial gate type in the Type dropdown combo box of the Gate Definition section.
The following entries are provided:
- Headwater reference
This dropdown combo box is used to select the reference point from which the upstream energy head will be computed. The following options are provided:
- Sill (Invert)
- Center of Opening
- Radial discharge coefficient
This entry field is used to enter the discharge coefficient for a radial gate opening. The discharge coefficient typically ranges from 0.6 to 0.8, depending on gate geometry and flow conditions.
- Trunnion exponent
This entry field is used to enter the trunnion height exponent, which is used in the radial gate equation. By default, the software uses a value of 0.
- Opening exponent
This entry field is used to enter the gate opening exponent, which is used in the radial gate equation. By default, the software uses a value of 1.
- Head exponent
This entry field is used to enter the upstream energy head exponent, which is used in the radial gate equation. By default, the software uses a value of 0.5.
- Trunnion height
This entry field is used to enter the height from the spillway crest to the trunnion pivot point. Alternatively, click the [Pick] button to measure the radical gate trunnion height above the gate sill from the SA/2D connection plot.
- Submerged orifice coefficient
This entry field is used to enter an orifice coefficient, which will be used for the gate opening when the gate becomes more than 80 percent submerged. Between 67 percent and 80 percent submerged, the software uses a transition between the fully submerged orifice equation and the free flow gate equations. When the flow is less than 67 percent submerged, the software uses the free flow gate equations. Clicking the […] button will display a lookup dialog box containing orifice discharge coefficients.
Weir Flow Over Gate Sill (Gate Out of Water)
If a gate is opened to the point where the top of the gate is no longer touching the water (or if an open-air overflow gate is being used), then the flow through the gate is modeled as weir flow. The software will automatically transition from gate flow to weir flow when the upstream head is between 1.0 to 1.1 times the height of the gate opening. Note that this section is not available when the user has selected the User Defined Curves gate type in the Type dropdown combo box of the Gate Definition section.
The following entries are required to model the weir flow through the gate opening:
- Weir Shape
This dropdown combo box allows the user to select the spillway shape at the overflow weir. The following options are provided: Broad Crested, Sharp Crested, and Ogee.
Based on the weir shape selected, the contents of the Weir Flow Over Gate Sill (Gate Out of Water) section will change to show the required information for that weir shape.
- Weir coefficient
This entry field allows the user to specify the discharge coefficient to be used in the weir flow equation for overflow. Note that different coefficients are used depending on units, such as US Units or Metric (SI) Units. Clicking the […] button will display a lookup dialog box containing weir coefficients.
If the user has selected the Ogee as weir shape, two additional entries: Spillway approach height and Design energy head are displayed in the Weir Flow Over Gate Sill (Gate Out of Water) section.
Note that the [Compute] button adjacent to the Weir coefficient entry field is used to compute the weir coefficient based on spillway approach height and design energy head.
- Spillway approach height
This entry field is used to define the height, which is equal to the elevation of the spillway crest minus the mean elevation of the ground just upstream of the spillway. Alternatively, click the [Pick] button to measure the spillway approach height above the spillway crest from the SA/2D connection plot.
- Design energy head
This entry field is used to define the height, which is equal to the energy grade line elevation minus the elevation of the spillway crest. Alternatively, click the [Pick] button to measure the design energy head above the gate sill from the SA/2D connection plot.
If the user has selected the Sharp Crested as weir shape, the following entries will be displayed in the Weir Flow Over Gate Sill (Gate Out of Water) section.
- Weir method
This dropdown combo box allows the user to select the weir method. The following options are provided: Weir Coefficient, Rehbock Equation, and Kindsvater-Carter Equation.
Based on the weir method selected, the contents of the Weir Flow Over Gate Sill (Gate Out of Water) section will change to show the required information for that weir method.
If the Weir Coefficient option is selected, the user is required to enter a weir coefficient in the Weir coefficient entry field that will be used for weir flow through the gate, for all head ranges.
If the Kindsvater-Carter Equation option is selected, the user is required to enter a spillway approach height in the Spillway approach height entry field. In addition, the Weir coefficient(L/b) dropdown combo box allows the user to select which form of the Kindsvater-Carter equation will be used to compute the weir coefficient. The form of the Kindsvater-Carter equation is based on selecting one of eleven equations that are based on varying L/b, where L is the width of the gate opening, and b is the top width of the approaching water upstream of the gate. If more than one gate is defined at a particular opening, the user must figure out an average approach width for the flow going to each gate.
If the Rehbock Equation is selected, the user is required to enter a spillway approach height in the Spillway approach height entry field, and the weir coefficient is then computed with the Rehbock equation. Alternatively, click the [Pick] button to measure the spillway approach height above the spillway crest from the SA/2D connection plot.
User Defined Gate Performance Curves
This section is used to define user-defined gate performance curves. Note that this section is only available when the user has selected User Defined Curves gate type in the Type dropdown combo box of the Gate Definition section. Otherwise, this section is unavailable.
The following entry is provided:
- Select curve set
This dropdown combo box allows the user to select a gate performance curve set for the selected gate group. Each curve set represents the headwater versus flow relationship for a single gate opening. When two or more identical gates exist in a group, the same curve set is applied to each gate. Note that user-defined gate curves represent headwater-only control and do not include downstream tailwater effects. To include tailwater influence, a full family of rating curves (headwater, tailwater, and flow) must be defined for each possible gate opening.
Clicking the [Define] button adjacent to the dropdown combo box displays the User Defined Gate Performance Curves dialog box, which allows the user to create or edit curve sets.
In the above dialog box, the Performance curve dropdown combo box lists all curve sets defined in the current scenario. Click the edit option (i.e., the pencil icon) to edit the curve set name. Click the [New] button to create a new curve set. Click the [Copy] button to copy the existing curve set along with its associated data to a new curve set. Click the [Delete] button to delete the selected curve set.
Under the Performance Curve Set Data section, the Headwater Elev entry defines the headwater elevations of the gate. The Gate Opening entry defines the gate openings for which performance curves are specified. The Flow values represent the discharge for each combination of gate opening and headwater elevation.
The Performance Curve Plot provides a graphical representation of headwater elevation versus flow. It updates dynamically as data are entered, allowing users to visualize gate performance behavior.
Outlet Rating Curve
This panel allows the user to define and manage rating curves for the selected SA/2D connection structure.
Rating Curve Specifications
This section is used to define general specifications for the diversion rating curve. The following entries are provided:
- Rating curve ID
This entry field allows the user to specify a name for an outlet rating curve.
- Outlet flow horizontal station
This entry field is used to define the specific horizontal position or stationing along the outlet structure where flow measurements or ratings are obtained. Alternatively, click the [Pick] button to select the horizontal station from the connection weir on the Map View.
- Outlet width (perpendicular to flow)
This entry field is used to define the width of the outlet structure perpendicular to the flow direction. Alternatively, click the [Pick] button to measure the outlet width from the connection weir on the Map View.
- Inlet location
This read-only field allows the user to select the inlet location where the water is coming from. Clicking the [Pick] button allows the user to select the inlet location from the Map View. Clicking the [Clear] button allows the user to delete the inlet location.
- Outlet location
This read-only field allows the user to select the outlet location where the water exits. Clicking the [Pick] button allows the user to select the outlet location from the Map View. Clicking the [Clear] button allows the user to delete the outlet location.
- Outlet flow based upon upstream
This dropdown combo box allows the user to select the type of diversion rating curve data that is to be defined. The following options are provided:
- Water Surface Elevation
- Flow
Note that based on the option selected, the contents of the table contained in a Diversion Rating Curve Data section will change.
Diversion Rating Curve Data
This section contains a table to define diversion rating curve data for the SA/2D connection. The following columns are provided in the table:
- Upstream Reference Water Surface Elev
This column is used to specify the water surface elevation at a reference location upstream of a connection structure.
- Outlet Flow
This column is used to specify the flow values (discharge) for the corresponding diverted flow through the SA/2D connection structure.
Note that if the Flow option is selected in the Outlet flow based upon upstream dropdown combo box of the Rating Curve Specifications section, the following table will be displayed:
- Channel Flow
This column is used to specify the flow values for the channel or outlet structure being analyzed. - Diverted Flow
This column defines the corresponding diverted flow through the SA/2D connection structure for the diversion rating curve.
Outlet Rating Curve Plot
This section displays a plot of the user-defined diversion rating curve. This visual representation allows the user to assess the behavior of the curve and make adjustments if necessary. Note that the rating curve axes change based upon the type of rating curve selected.
Outlet Time Series
This panel allows the user to specify a name for an outlet time series to be used as an additional outlet through the SA/2D connection structure. Then, a flow hydrograph can be specified for the SA/2D connection structure in the Unsteady Flow Data command. The flow time series will be labeled in the output based on the user-entered name for the outlet time series. Refer to this article in our knowledge base to learn how to use the Unsteady Flow Data command.
Time Series Specifications
The following entries are provided in this section:
- Time series ID
This entry field is used to define an ID for the outlet time series.
- Horizontal station for outlet flow
This entry field is used to select the horizontal station for an outlet discharge location on the weir geometry. Alternatively, click the [Pick] button to interactively select an outlet discharge location from the Map View.
- Outlet width (perpendicular to flow)
This entry field is used to enter the outlet width from the connection weir. Alternatively, click the [Pick] button to interactively measure the outlet width from the Map View.
- Outlet location
The user can click the [Pick] button to select the outlet location downstream of the weir geometry from the Map View.
The [Delete All] button can be used to clear all the data specified within this section.
Dam Breach
This panel allows the user to define dam breach specifications for the selected SA/2D connection. Dam breach data are only used for unsteady flow models and are ignored in steady flow models. Refer to this article in our knowledge base to learn how to define dam break data using the Dam Breach panel.
Linear Routing
This panel allows the user to define linear routing specifications for the selected storage area. Note that this panel is only available when Linear Routing option is selected in the Structure type dropdown combo box of the Connection Structure section under the Connection Data panel. Otherwise, this panel is disabled (i.e., grayed out).
Note that the Linear Routing panel can only be used to connect two storage areas.
The following entries are provided:
- Positive flow direction routing coefficient
This entry field defines the linear routing coefficient for the positive flow direction (in the defined flow direction of the storage area connection).
- Negative flow direction routing coefficient
This entry field defines the linear routing coefficient for the negative flow direction (opposite to the defined flow direction of the storage area connection).
- Overflow crest elevation
This entry field defines the minimum elevation of the spillway crest for flow to transfer from one storage area to the other. If both storage areas’ water surface elevations are below this crest elevation, then no flow is transferred between storage areas.
Geometry Adjustment
This panel allows the user to adjust the geometry for the selected SA/2D connection.
Adjust Storage Area Connection Geometry
This section defines the type of adjustment to be applied to the SA/2D connection geometry. The following radio button options are provided:
- No change
On selecting this option, no change will be found for the SA/2D connection geometry. Note that this radio button option is selected by default.
- Adjust elevations
On selecting this option, the entry field next to this option gets enabled, which allows the user to adjust the SA/2D connection geometry elevations by the defined amount.
- Adjust stations
On selecting this option, the entry field next to this option gets enabled, which allows the user to adjust the SA/2D connection geometry stations by the defined amount.
- Shift stationing
On selecting this option, the dropdown combo box and entry field next to this option get enabled, which allows the user to shift the SA/2D connection 1geometry stationing using an existing reference point. The user can select the corresponding reference point from the dropdown combo box and then assign the station to the reference point. The dropdown combo box contains the following entries:
- Leftmost Station
- Thalweg
- Rightmost Station
Adjustment Extent
After defining all the required parameters, the user can click the [Apply] button under this section to perform the geometry adjustment to the selected SA/2D connection.
Geometry Point Reduction Panel
This panel allows the user to reduce the redundant geometry points so that the SA/2D connection can be analyzed by HEC-RAS.
Geometry Point Reduction
The Current number of weir geometry points is a read-only field that shows the total number of geometry points associated with the selected SA/2D connection.
The Reduce number of weir geometry points to entry field allows the user to enter the target numeric value (geometry points) for the SA/2D connection. By default, this entry will show 490. However, the user can enter a different value if desired.
Clicking the [Preview] button causes the software to generate a preview of the defined geometry point reduction.
Reduction Extent
This section allows the user to perform the reduction of geometry points. The Apply reduction to dropdown combo box allows the user to specify the river regions for which the ground geometry point reduction should be applied. The user can choose from the following dropdown options:
- Current SA/2D Area Connection
- All SA/2D Area Connection
The user can click the [Apply] button to perform geometry points reduction to the specified SA/2D connection.