Aquaveo & Water Resources Engineering News

Do you want to know more about what happens when SMS completes post-processing for SRH-2D? When running SRH-2D, it helps to understand what exactly is happening during the post-processing phase of the SMS model run. This post will review how post-processing uses interpolation as it goes through SRH-2D.

To understand how post-processing fits into the SRH-2D process, first we need to look at what comes before it. When creating an SRH-2D model in SMS, the data is assigned as nodal data. This means that the boundary conditions, materials and other data is assigned to the nodes of the mesh. SRH-2D requires that the data be assigned to the center of the mesh elements (the centroid).

To allow the nodal data to be used by SRH-2D, SMS uses a pre-processing step that utilizes linear interpolation to interpolate the data that has been modelled in SMS into centroidal data for SRH-2D to use. After SHR-2D has finished processing the data, it creates results that use centroidal data. This is where the post-processor comes in.

The post-processor for SRH-2D takes the SRH-2D results and interpolates the data from centroidal data and converts it into nodal data. This allows SMS to import and display the solution data.

If the post-processor fails in its attempt, this usually means the centroidal data generated from SRH-2D is not valid. In this case, it could be possible that the model failed to converge even if SRH-2D managed to completely finish its model run. It could also be possible that SRH-2D was made to run an invalid model that resulted in empty solution sets.

For more information on how to use SRH-2D with SMS, see the XMS Wiki article on SRH-2D in SMS. Future versions of SMS may make use of centroidal data without the need to interpolate data.

Now that you understand a little more about how SMS handles post-processing, try out SRH-2D in SMS 13.1 today!

Have you been wanting to change the order that objects are displayed in the Graphics Window for your watershed projects in WMS? Within WMS, there is an option that can allow users to play around with this. This post will review how to utilize the Display Order functionality found in the Display Options dialog within WMS.

To locate the Display Order options in WMS, open up the Display Options dialog, either by clicking the Display Options macro or going to the Display | Display Options... command. Display Order should then be visible as one of the options on the left. There will be a checkbox for if Display Order should be activated or not. By default, this should be turned on.

As might be expected, turning the "Use Display Order" option on will cause objects to be displayed in the order laid out in the Display Order List. When the "Use Display Order" option is turned off, objects will be displayed in front of others based on which have XYZ coordinates closer to the user's eye rather than further. Depending on the scenario, it may be more visually helpful to have the option turned on or off.

For instance, in plan view, a delineated watershed may look better with display order turned on because when it is turned off, objects may look cluttered and bleed through each other. But for another example, in an oblique view, a delineated watershed may look better with display order turned off because when it is turned on, contours may look cluttered because objects are displaying primarily using display order instead of closer ones displaying in front of further ones.

When the "Use Display Order" option is turned on, the Display Order List will be active. The following options can be used to modify the order:

• Move Up: Moves the selected item one spot higher on the list.
• Move Down: Moves the selected item one spot lower on the list.
• Move To Top: Moves the selected item to the very top of the list.
• Move To Bottom: Moves the selected item to the very bottom of the list.

When an item has been moved as far high or low as it can go, any attempt to move it further higher or lower will result in a warning message that you have selected the top or bottom of the list, and to select an item below or above the current selection.

Try out experimenting with display order in WMS 11.1 today!

Have you wanted the legend to better represent the scale of your contours in your GMS projects, especially if your intervals are logarithmic? Having a well-configured legend can be very helpful in interpreting the contours of your project in the Graphics Window. And a logarithmic scale for your legend can be useful when you have wide-ranging values in your model that you want to represent in a compact and nuanced way. This post will review how to modify your contour legend options and how your legend is scaled.

To access the GMS Contour Legend Options:

1. First, contour options can be accessed either through relevant parts of the Display Options dialog (accessed from the Display Options macro) or through clicking on the Contour Options macro directly.
2. Look to the bottom-left of the dialog and turn on the Legend checkbox.
3. Click the Options button to bring up the Contour Legend Options dialog where all the contour legend options will be. This post won’t go into most of these options, but they include such options as setting the legend’s height and width, setting where in the graphics window it will be situated, and customizing its font.

The focus of this post will be the option to turn on Equal Color Segment Height. If the Contour Interval has been set to Number or Specified Interval, this option might not seem so useful, as the values for the contours should already be equally separated. But if the Contour Interval has been set to Specified Values, the Populate Values button will be clickable. This brings up the Value Population Method dialog, where different methods can be used to populate the values of the contours, including a Log Scale Method that will create a logarithmic rather than linear scale to the contours and their legend.

Normally, when a logarithmic scale is used for the contours, the legend will be as well, leading to a lot of the space on the legend being taken up by the higher values and a small amount of space being taken up by the more crowded lower values. Turning on Equal color segment height in the Contour Legend Options dialog can correct this, if that is how you want the legend to be displayed. This option will make the legend display logarithmically, with each logarithmic value displaying equally distant from each other. This means that the legend is no longer a linear gradient, but it better reflects the spread of a logarithmic scale when one is used.

Try experimenting with logarithmic contour intervals and other contour options in GMS 10.5 today!

Have you needed to modify how SRH-2D calculates flow around a structure? Using BCDATA lines in SMS may be able to help. New to SMS 13.1, the BCDATA line feature lets you specify a location where a water level or flow rate is extracted for a variable boundary condition.

The BCDATA line is primarily used to adjust how flow is calculated going into or leaving a structure. If there is high skew or rapid drawdown at the entry or exit of the structure then you should consider using a BC Data line. It indicates that rather than performing flow computations directly at the site of the structure, they should be performed at the location of the BCDATA line.

There are a few applications for a BCDATA line. For instance, it can be used on a structure such as a weir or culvert. When SRH-2D computes flow through or over a structure, it uses an average water surface elevation. When no BCDATA line is present, SRH-2D computes right along the nodes where the upstream boundary condition arc has been mapped. If an upstream or downstream BCDATA line exists, the water level can be computed there rather than at the actual edges of the structure. The BCDATA line should typically be located one or two cells upstream or downstream from the structure to get out of the zone of influence of the structure itself. This avoids drawdown caused by the flow going through or over the structure.

To create a BCDATA line and assign it to a structure, use the following workflow:

1. Use the Create Feature Arc tool to create a line a few elements long, ideally about 1 to 2 elements away from the upstream or downstream arc. Create it perpendicular to the arc and along the centerline.
2. Using the Select Feature Arc tool, select the line you have just created, right-click it, and select Assign BC… to bring up the SRH2D Assign BC dialog.
3. Set the BC Type to Bc Data. Make sure to provide a label name that is unique in the coverage. Then click OK to close the dialog.
4. Now select the upstream or downstream arc that is meant to be associated with the BCDATA line, right-click it, and select Assign BC… to bring up the SRH2D Assign BC dialog.
5. Scroll down to the General structure options section at the bottom. Depending on whether the arc selected is upstream or downstream, check the box by the appropriate BCDATA line option.
6. Use the drop-down that populates to select the label you previously specified for the BCDATA line. Then click OK to close the dialog.

The BCDATA line will now be assigned to the structure.

It can also be used on a Link or an EXIT-H boundary condition that you have specified using a rating curve. Normally, without a BCDATA line, SRH-2D computes the average flow directly at the line and then extracts the water level from the curve. When a BCDATA line does exist, the flow rate (Q) is computed across the BCDATA line, like a monitor line, rather than exactly at the boundaries.

Try using BCDATA lines with SRH-2D in SMS 13.1 today!