Moving from older PondPack versions to CONNECT Edition

Applies To 
Product(s): Pondpack
Version(s): V8i
Area:  Modeling
Original Author: Jesse Dringoli, Bentley Technical Support Group


The purpose of this article is to guide users who had previously used the older PondPack version 10.0 (circa ~2006, not to be confused with CONNECT Edition), 9.0 or 8.0 to become accustomed to the new user interface seen in V8i and CONNECT Edition ( and 10.02.XX.XX)


PondPack CONNECT Edition training can be found here: 

In particular, focus on the video "Introduction to PondPack V8i Basic Features"

What happened to the subarea and hydrograph queue node elements? 

In previous versions of PondPack, the user could use the "Hydrograph Queue" element to inject a user defined hydrograph. The "Subarea" element was used to represent drainage areas.

The functionality of these elements are now included in the Catchment element in PondPack V8i. A catchment is a polygon representation of your drainage area, using a certain runoff method (such as Unit hydrograph).

To model a hydrograph queue node (user defined hydrograph), you would select "user defined hydrograph" as the Runoff Method, then enter your hydrograph using a table of time vs. flow. Your user defined hydrograph would then be injected into the system, at the point identified in the catchment "outflow node" property.

See more here:

Inserting user defined flow or hydrograph into the model


Where is the "add link" element? (black line) 

In previous versions, the "Add link" element was used to direct outflow from one node to another. The Add Link is no longer an element in V8i. To connect a catchment to the rest of the model, you would simply select the appropriate element for the "outflow node" property of the catchment. You'll then observe a dashed line connecting the center of the catchment to the discharge point.

Aside from catchments, the equivalent of the add link tool in V8i would be to use the "conduit" element, selecting "virtual" as the conduit type in the conduit properties. This would instantly carry the upstream hydrograph to the downstream node without attenuation (which is what the add link tool did in older versions). For example, Catchment > Junction > conduit (set to Virtual) > Outfall > Pond.


What happened to the pond route? What do I have to do now to model my pond outlet structure? 

In previous versions, the pond outlet structure was designated by the red "pond route" link tool, which directly connected to the pond node. However, in V8i, ponds are polygons. So, the Pond Outlet Entrance node is used to identify and place an icon at the point within the pond where the outlet structure is located. A link element called a Pond Outlet is then connected to the Pond Outlet Entrance. The Pond Outlet link will then connect to the element that the pond outlet structure discharges to. For example, Pond > Pond Outlet Entrance > Pond Outlet link > Outfall.

The outlet structure is created under Components > Composite Outlet Structures. Your composite outlet structure is then assigned to the pond outlet link, not the pond outlet entrance. In the properties of the pond outlet, select "Yes" for "Has Control Structure?" then select your composite outlet structure from the drop-down next to the "Composite Outlet Structure" field.

See this link for additional information: How do you attach a pond outlet to an outfall in PondPack V8i?

What happened to the reach route? How do I model a channel in V8i? 

In previous versions, the "Reach" element was used to attenuate a hydrograph, typically over a length of channel or some other cross sectional geometry. The reach link is now called a "conduit". The conduit link element can be configured as many different shapes, such as irregular channel or circular pipe, and will attenuate flow.

It is important to understand that the water surface elevation in the channel does not affect upstream elements. For example, if your pond empties into a channel that could back up and eventually cause reverse flow into the pond, you'll need to use another modeling approach.


What happened to the Catalog Explorer? 

 In previous versions, the Catalog Explorer was used to define and store reusable information, particularly storm events. Global library information previously seen in the "catalog explorer" is now found in the Engineering Libraries. Go to Components > Engineering Libraries to view the engineering library manager. A variety of information can be exported to and imported from the various engineering libraries available. For example, the purple book icon under Components > Storm Data is used to export and import storm information to/from the Storm Event Groups engineering library.

Storm events would not be created directly in the engineering library manager. You storm event is created under Components > Storm Data. When done, you can export the storm data to the engineering libraries. When you need to use it in other models, simply import from that library, in the Storm Data dialog.


Did the model layout representation change from schematic to scaled? 

Yes - the elements of your detention pond model can now be drawn to scale. In previous versions of PondPack, the network layout was a schematic, with nodes and links defining connectivity only.

For example, catchments and ponds are now drawn as polygons and PondPack V8i computes the area of the polygon based on its shape and size. The length of a conduit is based on the distance between its end nodes. Note however that you can override these scaled areas and lengths with user defined lengths if you'd like, irrespective of the length/size seen in the drawing pane.
You can also place a background such as a DXF or shapefile, using View > background layers. This can be helpful so that you lay your elements out in the correct scale by tracing over the background.


Is the scaled area of my pond polygon automatically used in the volume calculation? 

No - although the scaled area is used for catchments, the ponds represent three-dimensional space, to occupy volume. So, you must still define the pond using one of the volume methods such as elevation-area or elevation-volume tables. The scaled area of the pond can be useful as a reference, for the top pond elevation value. 


Is there an easier way to lay out a schematic representation of my pond or catchment? 

Yes - hold down your CTRL key on your keyboard, left click in the drawing pane, move your mouse slightly, then left click again. This will lay out a pentagon shaped polygon for your pond or catchment. If you are using this method to represent a schematic of your catchment (the area not correlated with the area of the polygon), make sure you choose "false" for "Use Scaled Area" in the catchment properties, then enter the area in the "Area (User Defined)" field. 


Has there been a change to the hydraulic calculation engine between V10 and V8i? Should I expect to get comparable results between the two versions? 

Although the user interface and features in PondPack V8i are quite different from previous versions, the basic hydraulic calculation engine is essentially the same. The equations and calculations used and how they are applied have not changed.

How can I extend the duration of the simulation beyond 24 hours?

See: How do I extend my total simulation time to show results beyond 24 hours?


Why is it called "V8i"? Hasn't there already been a PondPack V8? 

Although there has indeed already been a PondPack 8.0 (circa ~2003), PondPack V8i integrates with Bentley's V8i product line (Microstation V8i, Projectwise V8i), so the versioning was kept consistent. 


Can I open models saved in older versions? 

Yes. PondPack V8i can directly open models saved in version 6.1, 7.0, 7.5, 8.0, 9.0, 10.0 and 10.1, using File > Open. The scenario, alternatives, storm events, etc necessary for you to compute multiple return events will be imported automatically.


Can I open V8i models in previous versions? 

No - PondPack V10 is not forwards compatible. Once your model is saved in V8i, you cannot open it in previous versions. There is no method to "save down" to the older version. 


Does a user-defined hydrograph count toward my pond limit? 

In previous versions of PondPack, the hydrograph queue node element represented a user-defined hydrograph and would count as a pond (when checking the pond limit in your license). In PondPack V8i, the user defined hydrograph option for a catchment does not count toward the pond limit. 


The system requirements state that AutoCAD 2009 is supported, but a shortcut is not being created for me. Why not? 

The PondPack for AutoCAD 2009 shortcut is located in the installation folder. Typically this is C:\Program Files\Bentley\PondPack8\. You can move this shortcut file to your desktop or start menu folder for easier access.


Why do I get a message that there is no valid PondPack for AutoCAD license, when opening the PondPack for AutoCAD shortcut? 

The use of PondPack inside of AutoCAD requires the AutoCAD module in your license. You are always able to use PondPack in Standalone and inside of Microstation, but AutoCAD integration is an extra cost. Please contact Bentley's sales department for more information on adding AutoCAD to your license.

If you do have AutoCAD in your license or if you're not sure, go to Start > All Programs > Bentley > PondPack > Municipal License Administrator. Look in the features column next to Bentley PondPack to see if AutoCAD is included with your license. To ensure that license is configured, click the Bentley PondPack row and click "make default".


Why isn't Windows 2000 a supported Operating System? 

This is due to the fact that PondPack V8i requires a Windows component called Microsoft .NET Framework. The version of .NET framework required by this version of PondPack is 3.5, which Windows 2000 does not support. Therefore, PondPack V8i cannot run in Windows 2000. 


What is the purpose of these "Scenarios" and "alternatives"? 

A scenario is a collection or configuration of alternatives, which describe various characteristics of your model. For example, the physical property information (such as channel invert) is stored in the Physical alternative but the outfall tailwater information (free outfall, time-elevation curve, etc) is stored in the Boundary Condition alternative. Each scenario can use a different configuration of alternatives, which allows you to compute multiple "what if" situations in the same model file.

For example, you could analyze the differences between having a 10" conduit versus a 16" conduit for the same return event, by using different physical alternatives in the two scenarios. When you make a change to your model, it changes the data in the appropriate alternative assigned to the scenario you are currently viewing.

The other common use of scenarios and alternatives is to examine multiple return events. The Rainfall Runoff alternative stores the storm event selection, so if you'd like to examine multiple return events (for example, 10, 50, 100 year), you would set up a scenario for each one. Each scenario would use its own rainfall runoff alternatives, each configured with the appropriate storm event.

Note: a special scenario creation tool is included in PondPack V8i, to make it easier to create scenarios for predeveloped/postdeveloped conditions and for multiple return events. This tool will appear when you first create a project and is also available within the Scenario manager.


How can I use the Active Topology feature/alternative? 

The active topology alternative stores information on which elements are active and which are inactive. Inactive elements are not considered when you compute the model, as if you had deleted them. Inactive elements are colored gray by default but you can configure them to disappear from view.

One example of a case where you might want to use active topology would be predevelopment versus postdevelopment. Meaning, you may need to compute an area in it's pre-developed conditions and then compute it after development occurs. Your postdevelopment scenario might have an active pond and several "developed" catchments, whereas the predeveloped scenario would likely not have a pond and the catchment would describe undeveloped conditions. In previous versions, the user would either need to create two separate models, or two separate networks in the same model to describe these conditions. In V8i, you would use a single model with multiple scenarios to describe this.

The postdeveloped scenario's active topology alternative would describe the pond and developed subareas being active, whereas the predeveloped scenario's active topology alternative would have those elements inactive, with only the elements present in the predeveloped conditions active.

Note that if you're using the modified rational method, there is no need to create separate pre/post scenarios. This is because both the pre and post conditions are handles in the modified rational catchment. You'll still need to create separate scenarios for each return event though.


When I make an element inactive, it still shows up in gray. Can I have inactive elements disappear instead? 

Yes. This is controlled under Tools > Options > Global. If you'd like inactive elements to disappear from view, uncheck "Display Inactive Topology?". Unchecking this option is recommended and will results in a more intuitive model display in most cases. Keeping this option checked will remind you of the elements that are no longer active though. 


Why am I being asked if I'd like to create pre/post scenarios, when starting a new model? 

The pre/post scenario creation wizard allows you to quickly generate the scenarios and alternatives necessary to analyze pre and postdeveloped conditions for multiple return events in the same model. If you choose not to use this, you'll need to manually set up your scenarios and alternatives.  


What is the workflow for setting up pre and postdeveloped conditions for multiple return events? 

1) Choose "yes" when asked if you'd like to create pre/post scenarios upon creating the model, or select this tool from the "new" button in the scenario manager.

2) Enter labels for pre/post scenarios and list the return events to be analyzed.

3) After the scenarios and alternatives are generated, go to Components > Storm Data and either create or import your storm events.

4) Go to Components > Global Storm Data and select the storm events corresponding to each return event.

5) Select one of your predeveloped scenarios as the active/current scenario and lay out or import the predeveloped conditions (for example, a catchment going to an outfall.)

6) Select one of your postdeveloped scenarios as active/current and lay out the postdeveloped conditions. The elements you lay out while in the postdeveloped scenario will be inactive in the predoeveloped scenarios.

7) If the elements from the predeveloped scenarios are different in the postdeveloped scenario, make the necessary changes. For example, if the Tc is different, make the change while in your postdeveloped scenario - the predeveloped Tc will remain intact for the predeveloped scenarios. If an element from the predeveloped conditions should be gone in the postdeveloped conditions, make the element inactive using the "is active?" property or the Active Topology Selection tool under the Tools menu. For example, if you have a catchment called "pre conditions" in the predeveloped scenario, but that catchment has a different shape in the postdeveloped conditions and should be named "post conditions", then make the "pre conditions" catchment inactive in the postdeveloped scenario, then lay out and configure the "post conditions" catchment. Since the default active topology setting is Inactive and since the predeveloped scenarios use a different active topology alternative, the "post conditions" catchment will be inactive in the predeveloped scenario and thus not considered in the calculations.


What do I have to do to compute multiple return events at once? 

In previous versions, you could select multiple return events in the Compute dialog and PondPack would run multiple simulations at once. In V8i, the concept of Scenarios and Alternatives is used, and you must use the Rainfall alternative to handle this. Each return event is described in a rainfall alternative, and each scenario only has one rainfall alternative assigned to it. So, to compute multiple return events, you must create multiple Scenarios, each with the appropriate rainfall alternative assigned (and the other alternatives all the same). You can then compute all scenarios at once, using the Batch run feature. This is found in the compute dropdown button in the Scenario manager (Analysis > Scenarios).

An easier way to set up your model to analyze multiple return events would be to use the Scenario Creation wizard. This will create the scenarios and alternatives for you automatically. Either choose "yes" to the prompt that normally appears when first creating a model, or go to Analysis > Scenarios, click the "new" button and choose "New pre/post development scenarios". If you're not doing a pre/post analysis and simply want to create the scenarios and alternatives necessary to analyze multiple return events, then select "Post development only" as the scenario creation type and enter a label for your scenarios. In the table at the bottom, enter a label for each return event you'd like to analyze. When you click create, PondPack will create a scenario for each return event, each with its own rainfall runoff alternative. To tell PondPack which storm is used for which scenario, first create or import your storms under Components > Storm Data. Once done, go to Components > Global Storm Data. In here, you will see an alternative corresponding to each return event (based on the labels you had chosen). Select the corresponding storm event next to each one.

Note: If you have opened a model saved in a previous version (such as 10.0), you do not need to set up the scenarios and alternatives for multiple return events. These will all be imported for you - simply run a batch in the scenario manager to compute multiple return events.


What if I use the pre/post scenario creation tool but want to go back and add another return event? 

If you had used the Pre/Post Scenario Creation tool at some point in the past, but later want to add another return event, you'll need to add a new rainfall runoff alternative and two new scenarios. First, go to Analysis > Alternatives and expand the Rainfall Runoff Alternative. Right click on the base rainfall runoff alternative, choose New > Child Alternative and give it a name corresponding to your new return event. For example, you may already have a '10 year' base alternative with '25 year' and '100 year' child scenarios. If you were adding the 50 year scenario as a child to the 10 year, it would show up on the same 'level' as the 25 and 100.

Next, click Analysis > Scenarios, right click the base predeveloped scenario, choose New > Child scenario and name it appropriately. Double click the new scenario and assign the newly created rainfall runoff alternative. For example, if you had just added a 50-year rainfall runoff alternative, select it as the "rainfall runoff" alternative for your new predeveloped 50 year scenario.

Next, right click the base postdeveloped scenario, choose New > Child scenario and name it appropriately. Just like with the new predeveloped scenario, double click the new postdeveloped scenario and assign the newly created rainfall runoff alternative.

Next, if you have not done so already, import or create your new return event's storm data, under Components > Storm Data.

Lastly, Go to Components > Global Storm Data and select the new storm event for the newly created rainfall runoff alternative.


How can I import storm information from the catalog explorer of old versions? 

In previous versions, storm information such as rainfall curves, IDF curves, design storms, etc could be stored in the catalog explorer. This allowed the user to reuse these storms in any project. When you open a V9/10 model in V8i, any storm information saved in it will be imported. You can then export that information to V8i's engineering library for future use.

To import storm information stored in V10's catalog explorer but not stored in any V10 model file, go to File > Import > PondPack 9/10 Engineering library data. You will now need to browse to the .xml file, which stores the catalog explorer data that you wish to convert to V8i. This is the file cabinet icon seen in V9/10. If you are not sure where your xml file is located, open PondPack V9/10, right click on the file cabinet representing the library item in question (in the catalog explorer) and choose "properties". The path to the .xml file will be displayed. After selecting the v9/10 XML file, you will then be prompted for a location to save the V8i format engineering library file. Choose a safe location and click OK. The library will be automatically registered in V8i's Engineering Library manager, so you can now begin using it with your projects.If you encounter a second prompt stating that a reference library cannot be found, then you are likely importing a design storm catalog, which references one or more rainfall curve catalogs. In this case, you'll need to click "Yes" and browse to the folder where the rainfall curve catalog XML file is located.


How can I reuse storm information in subsequent projects, like with the catalog explorer of previous versions? 

To do this, first create the storm information for your locale, under Components > Storm Data. For example, create a new Time-Depth storm event group, with a 2, 10, 50 and 100 year storm events within it. Then, click the name of the storm event group on the left side, click the purple book icon and choose to export to library. If you'd like to be able to share your storm collections, it is recommended that you create a new library to store them. To do this, right click on "Storm Event Groups" in the engineering libraries window, choose "create library", then save the .xml file in a safe location. Click the name of that library and click the "select" button to export your storms to your engineering library. This is equivalent to the Design Storm section of the Catalog Explorer in previous versions.

Now, if you need to use these storms again in another model, first go to Components > Storm data. Then, click the purple book icon and choose "import from library". Lastly, expand the name of your engineering library XML file, select your storm and click "select". Your storms will appear in the Storm Data window and can now be used in your model.

If you'd like to share your standard storm event groups, simply copy the .XML file that you had saved, to a safe folder on the other computer. Then, inside PondPack on that computer, go to Components > Engineering libraries. Click "new" > "Add Existing" and browse to the XML file. The storms will now be available for import in the Storm Data dialog.

Note that if you use Bentley Projectwise, you can elect to store engineering library data there, for access on multiple computers. To do this, first copy the XML file to Projectwise. Then in PondPack on each computer, click Components > Engineering Libraries. Click New > Projectwise Add Existing Library, then connect to Projectwise and browse to the XML file.


How can I apply a rainfall depth to a dimensionless curve to create a storm event? 

First go to Components > Storm Data. Click the new button and select "Time-Depth" or "Time-Intensity" and provide a name for your storm event group (equivalent to the "Design Storm" in previous versions). On the right side, click the new button and select "Add return event from dimensionless curve". In the window that appears, expand the library of choice and select your dimensionless rainfall curve. If you need to create a custom one first, you can do so under Components > Engineering libraries. In the "generate storm event" window that appears next, provide a label, return frequency, total depth, etc and click OK. Your time-depth or time-intensity event will be constructed based on the entered depth and dimensionless distribution. 


I placed an outfall on top of a pond but the flow doesn't seem to be entering the pond, or I get a message that the pond is not connected to an upstream element. Why? 

By default, the outfall element will be configured as free outfall. This means that upstream flow reaching the outfall will leave the system. If you need to have the upstream flow empty into a pond, ensure that you select "boundary element" as the outfall's boundary condition type, then pick your pond as the "boundary element". 


How do I view my results? 

There are many ways to view results:

1) In the calculation summary after computing the model, core result information such as the hydrograph volume , peak flow and max water surface elevation are shown. You can get back to this under Analysis > Calculation Summary.

2) The Report Builder tool seen in previous versions is still available, either by clicking the "report" button in the calculation summary or by going to Report > Report builder. This contains copious amounts of text results and calculation related information.

3) Graphs can be generated for many results, under View > Graph or by selecting your element(s) and choosing "graph" under the right click menu. For example click a pond, hold down the CTRL key, click another pond, right click the pond and choose graph.

4) The Properties window shows results for a particular timestep, for any element. For example, go to Analysis > EPS Results browser and select a timestep. Double click an outfall in your drawing to open the properties window. Under the "Results" section of the properties, you'll see the elevation and flow for that timestep, as well as other information.

5) Flextables are a convenient way to show information for many elements at the same time, in tabular form. For example go to View > Flextables and double click the Catchment Table. Click the yellow edit button at the top of the Catchment table and configure which fields you'd like to see. When done, you'll have a table of your catchments, showing the results you'd like to see.


How do I display a time series of an attribute such as time vs. elevation for multiple return events in the same graph? 

First, compute all scenarios desired. Then create a graph of the element(s) in question. For example, right click a pond, choose "Graph" and select the attributes you'd like to graph. In the graph series options window, you will also see a Scenarios section on left side. Select all the scenarios you'd like to graph that attribute for by clicking the check boxes. When you click OK, you will see a graph of those attributes, for all the scenarios specified.

When you're viewing the graph, you can get back to the series options by clicking the button at the top or using right click > graph series options.


Can I customize the properties window to only show fields I'm interested in? 

Yes. By default, PondPack will show many attributes in the properties window of your elements and you may want to reduce clutter and show just the fields you're concerned with. PondPack V8i includes some default customizations for common modeling situations, which can help this. For example, select "Basic Results (Predefined)" from the dropdown menu at the top of the properties window to see only basic results fields.

You can also create your own customizations to show the fields you want. To do this, go to View > Customizations. Create a new customization and select which attributes you'd like to show in the properties for each element type. Then, select your customization from the dropdown at the top of the properties window to apply the filter.


How can I show multiple scenarios / return events in the Master Network Summary? 

First, either compute the desired scenarios one by one, or perform a batch run in the scenario manager. Then, go to Report > Report builder. In the Scenario Selection window that appears, place a check in the box next to the scenarios you'd like included in the report, then click OK. Now when you view the Master Network Summary, it will include results for all the scenarios you selected. 


Is it possible to view old-style text reports?


How can I print just the rating curve plot for my outlet structure? 

In the composite outlet structure manager, the report button provides a full report of both the rating tables and curves. To print only a particular rating curve graph, right click on the X axis of that graph, choose "graph properties" and click the print tab. 


Report Builder has so many reports. Can I customize which ones show? 

Yes. In the Report Builder window, click the Report Filter button (funnel icon). Click the new button to create a new filter, name it, then double click to configure it. In this window, use the check boxes to select which reports you'd like to see. You can create multiple filters depending on the types of results you're interested in. Back in the main Report Builder window, select your report filter from the dropdown to filter the available reports. 


Once I set up my report filter the way I like it, how can I share it with my colleagues so they have the same filter? 

In the Report Builder window, click the report filter button, then click the export button. Choose a location and name, then save the .xml file. Send this file to your colleague's computer. In their PondPack, click the "import" button in the report filter window and select the .xml file to import the filters. 


How can I view the cross section and rating curve of a channel/conduit? 

First, lay out the conduit and configure its properties. Either enter a user defined shape or select from the conduit catalog. Make sure to enter the conduit's elevation data. Right click on the conduit from the drawing pane, choose "Channel rating curve" and the rating curve and cross section will be computed and displayed. The window that opens has a dropdown selection to view the cross section drawing, rating curve (elev vs. flow) and other various useful graphs. 


Which end of the conduit do the "Flow" and "Elevation" result fields refer to? 

The "Elevation" result field shows the elevation at the upstream end of the conduit. The "Flow" result field shows the Flow at the downstream end of the conduit.  


What is the difference between a "composite outlet structure" and an "outlet structure"?  

The composite outlet structure refers to a collection of individual structures acting as the pond outlet. For example, composite outlet X may consist of an orifice and a weir. The composite outlet structure is what you assign to the pond outlet link, which tells PondPack to use that 'composite' collection of structures as the pond outlet discharging to the element downstream of the outlet link. 


Do I still have the option of having PondPack use stored EQT tables for ICPM outlets? 

Yes. In previous versions, a check box was available in the pond route properties, to "Use EQT table?". This option allowed the user to compute the EQTW table for the individual outlet structure first and then have PondPack re-use that table during the full network calculations, instead of re-computing it. This feature saves on calculation time and is still possible in V8i, using these steps:

1) Go to Components > Composite Outlet Structures and create your composite outlet structure. A tailwater type of "Interconnected ponds" must be selected to use EQTW curves.

2) Click the name of your composite outlet structure and choose "Yes" for the "Store Elevation-Flow-Tailwater table?" property.

3) Select "Create new EQTW series" for the "Elevation-Flow-Tailwater" field.

4) Compute the EQTW rating curve by clicking the green compute arrow at the top. After calculation, the EQTW table will be stored in the Elevation-Flow-Tailwater manager.

5) Close the Composite Outlet Structure manager and look at the properties of your pond outlet link.

6) Select "No" for the "Has control structure?" field, "Yes" for "Use Elevation-Flow-Tailwater Table?" and select the EQTW table entry from the "Elevation-Flow-Tailwater Table" field. Now when you compute your model, it will use the stored EQTW table instead of recalculating it.


Why do I not see progress details when computing an outlet rating curve or ICPM model? 

For large and/or complex composite outlet structures, it may take a while to compute the rating curve. For large models with ICPM pond routes, it may take a while to compute the ICPM routing. By default, no detailed progress indicator is shown. To enable the display of these details, select "true" for the "Show status" field in the calculation options for your active scenario (Analysis > Calculation options). Then, when you compute the outlet rating curve, you'll see calculation progress (current tailwater elevation, headwater elevation, convergence, etc.)

Note: enabling the display of calculation status will typically cause an increase in runtime.


How does the new Vortex Valve outlet structure element work? Vortex valves are a type of outlet structure used in some ponds.

They have a unique rating curve, which may help reduce the require storage volume, when compared to other outlet structure types.

In PondPack V8i, they are essentially handled as user-defined rating curve outlet structure types, but can be stored in an engineering library. Meaning, they are a defined relationship between the pond water surface and the corresponding outlet structure discharge.

First, you must either construct the vortex valve rating curve under Components > Vortex Valves (you can copy/paste the data from manufacturer documentation), or import from a library (some default HydroInternational vortex valves are included). Then, in the Composite Outlet Structure manager, right click your composite outlet structure, choose new > vortex valve. In the properties of the vortex valve entry, select your vortex valve from the "Vortex Valve" dropdown and enter an "Elevation".

The "head" values in your vortex valve rating curve are depths above the "Elevation" that you enter. For example, say that the flow at a "head" of 1.0ft on your vortex valve rating curve is 2cfs and you enter 995ft as the "elevation". This means that when the water surface of the pond is 996ft, the flow out of this outlet structure will be 2cfs.

Note: Be careful when using vortex valves in an interconnected pond scenario; the rating curves assume a free outfall.


In step 1 of Pondmaker, what does the "design scenario" and "target scenario" represent? 

The Design scenario represents the scenario which you are designing the pond for. It is typically the Post-development conditions, where catchment runoff is higher than the predevelopment conditions.

The Target scenario (when using scenario as the target flow/volume source type) should be the scenario describing the conditions that your pond will be designed to reduce flows down to. So, it is typically the "predevelopment" scenario for the same return event. You will design the pond and outlet to attenuate the peak flow from the Design scenario down to the target value from the Target scenario.


When using the modified rational method, what is the difference between using "Scenario" versus "Modified Rational Catchment" as the "Target Flow/Volume Source" in step 1 of Pondmaker? 

Under normal circumstances you should use the "Modified Rational Catchment" as the "Target Flow/Volume Source", when using the Modified Rational method. When doing this and selecting your modified rational catchment as the target element, Pondmaker uses the predeveloped peak from that catchment as the target peak flow to design against. This is based on the Predevelopment Tc, Predeveloped C and Predevelopment area (if the outflow criteria is set to Pre-Development) or the "Target" flow (if the outflow criteria is set to User Defined) entered in the catchment properties.

If you choose "Scenario" as the "Target Flow/Volume Source", the target peak flow that your design will be based on will come from the computed peak of the hydrograph at the select target element, in the selected scenario. In this case, you would not want to select the same scenario as your design scenario, with the modified rational catchment as the target element. This is because the hydrograph in that scenario, at that element would be the design/peak flow, not the target/allowable flow.

One possible reason for using "scenario" as the target flow/volume source would be if you had a scenario using the custom critical Td option to mimic existing/predevelopment conditions for the modified rational runoff hydrograph.


What do all those lines represent, in the graph seen in steps 4 and 5 of Pondmaker? 

The bold blue line represents the rating curve of the outlet structure you computed. The horizontal dashed lines represent the estimated water surface elevations for each of your return events. Each of these has an orange dot, corresponding to the target peak outflow that you're designing for. The orange line connects these dots, so it is the target rating curve. Basically this is a good way to visualize how close your trial outlet structure is at achieving your design goal for each return event. The goal is to get the blue outlet rating curve as close as possible to the orange target rating curve. When you tweak your outlet structure and click the green compute button, the outlet rating curve will update, to give you a good visual idea of how well the adjustment was. 


What is the purpose of the "Computed Outflow Volume vs. Target" field in Pondmaker? 

This field will show you if your designed pond and outlet are able to reduce the total pond outflow volume to be within the tolerances of the total outflow volume in the target (typically pre-development) condition. If you do not use infiltration with your pond, the computed outflow volume is going to be the same as the total inflow volume before implementing the pond. This is because the pond only attenuates the flow - the same mass of water still flows out of it. So, you may not need to be concerned with this field, unless you are required to reduce the outflow volume by way of infiltration.

In the routing step of Pondmaker, if you'd like to implement infiltration to reduce the outflow volume, first go back to step 3 (pond dimensions) and select your infiltration method. Then, click back to the routing step and compute it.

Note: the pond dimensions and outlet design steps of Pondmaker will not account for infiltration.


I don't like the way the report looks in Pondmaker. What options do I have? 

You can easily export the worksheet data for the Design and Routing tabs to another program, such as Microsoft Excel. To do this, click the Design or Routing tab, then click the blank gray cell at the upper left corner to select the entire table. Press CTRL+C on your keyboard to copy the data into clipboard. Then, open your external application and paste the data in. You can format the table the way you'd like it, then print.

For the various graphs available in the Pondmaker process, you can right click the X axis, choose "graph properties", click the "print" tab and print from there.


Can I still choose to store computed hydrographs? 

Where do I find Pond Volume Results?