Starting in the SELECTseries 6 release of WaterGEMS and WaterCAD, the Flushing tool has greatly been improved. The new flushing module is easy to setup, easy to run (you can run a selected event or all events), and easy to generate printer ready reports. Both conventional and unidirectional flushing can be arranged under certain area or study. In earlier versions of WaterGEMS/CAD before V8i SELECTSeries 4, flushing was controlled in a basflushing alternative.
For the CONNECT Edition release of WaterGEMS and WaterCAD, the Flushing model can be accessed by going to the Analysis tab, then selecting Flushing > Flushing. For the V8i releases starting with the SELECTseries 4 release, you can access this by going to Analysis > Flushing Manager. If a user opens a project created in an earlier build, the data in the flushing alternative will be transferred to the Flushing manager.
Starting with WaterGEMS/WaterCAD, the following criteria is now available:
For more information on using Flushing in SELECTseries 4 and 5, see this article.
Reasons to Flush
Work Flow for Modeling Flushing
To perform an analysis of a set of flushing events (i.e. a flushing area), the user must create flushing events. Upon opening the flushing manager initially, there will be a default study, "Flushing Study" which will have one area called "Base Flushing" in the left pane.
Note that any demands from other elements such as junctions and customer meter elements will be accounted for during the flushing run. Meaning, a flushing run will not have only a demand on the flushing node - it will use the baseline scenario's base conditions (including demands), and flush the hydrant(s) along with those other conditions (such as demands, controls, etc).
The user creates new studies or areas by right-clicking on the study node in the left pane. By right-clicking on the area a new event can be created.
Identifying the Buttons Left to Right
Within a flushing area, the user defines the representative scenario, target velocity and shear stress, pipe set, method to determine flow (emitter or flow), boundary valves and auxiliary output if desired. It is a good idea to create a selection set corresponding to the pipe set before entering the flushing manager.
The user then creates events within an area. It is assumed that the flushing events are conducted in the order in which they are listed. The key to order is usually to flush from clean water into needed areas. To change the order of the events or areas, use the shift-up and shift-down buttons.
Conventional events are made up of the hydrant (or junction) to be flowed. These events have an advantage of being very easy to set up a large number of conventional events in essentially one step. The user will see the Selection dialog where individual junctions or hydrants are selected. Junctions or hydrants can be selected by polygon or they can be selected based on a selection set that has been previously defined. If not all the nodes in a polygon are to be flowed, it can be helpful to have a selection set done already.
The events tab enables the user to get a quick view of the events that are contained in the area, and if desired, make events active or inactive for the next run. The notes tab enables the user to enter a text description of the area.
For UDF events, they must be created one at a time because the user must select flowed elements, controlled elements, and optionally the pipe run to be flushed. In this case a special form of the select dialog is opened.
Quick Pipe Run Creation Tools
Prior to WaterGEMS and WaterCAD V8i SELECTseries 6, the unidirectional flushing event element selection only allowed you to select one pipe at a time to add pipes to the flushing event pipe list. The Add Pipe Run Elements tool now has the ability to pick a node and add pipes in the shortest path between the selected node and the nearest end nodes of pipes already selected.
An Undo button has also been added to let the user undo the last element selection. Undo works for all types of element selections, including adding pipes in a path, adding single pipe, adding operational open element, adding operational close element and removing an element.
The Highlight Previous button will highlight the previous event's elements.
With the new Auto-isolate feature you can quickly identify candidate isolation valves to close off the selected pipe run, which will save you time when compared to manually picking valves to close with the third button. Be sure that no demand nodes are isolated using this tool.
In creating a UDF event,
Once an event is created, if the event is expanded in the left pane, there is one row for each element that is flowed, closed, or part of a pipe run.
The element label and type are properties of the element selected and the status is an editable field (unless it is a flushing element such as a hydrant) indicating if the element is open/closed, flowed, or part of a pipe run. The flow emitter or flows specified in an area tab can be overwritten by checking the Specify Local Flows check box for that element and inserting a different flow or emitter.
Note fields are very important if the results of the flushing analysis are to be given to operators to locate elements to operate. The notes may included an address for a hydrant or at a location of a valve that needs to be closed.
Flushing Results Browser
The flushing results browser contains the results of a flushing run listed by event. The content of the browser corresponds to the current scenario. If it is not a flushing output scenario, no events would be displayed. The scenario can be switched to the flushing browser in the main drawing or by picking the button next to the output scenario selection in the right panel of the flushing manager.
The new fields have been added to the flushing results browser which are Time (recommended flushing) and Volume (recommended flushing), which are calculated by multiplying the "Safety Factor" by the related "minimum" value.
Before opening the browser it is helpful to set up color coding and annotations that will highlight the flushing events. Usually color coding pipes by velocity or shear stress, and junctions or hydrants by demand, will be the most useful.
An example of how this might work would be to toggle "Include nodes with pressure less than" and enter a value, such as 40 psi. You can then set up a color coding for all junctions based on pressure. After opening the Flushing Results Browser, you can highlight one of the flushing events. Only the nodes where the pressure was less than 40 psi were color coded (nodes near the pipe run are also color coded, but may have a different color based on the color coding you have set up). All other nodes were set to the default color. If you select a different flushing event, different elements were highlighted. This allows the user to get a visual representation of what is happening during different events.
You can also set up Nodes of Interest, which is an optional collection of nodes that you may deem important in the model. If you choose to include Nodes of Interest, these will also be color coded, even if the pressure doesn't fall below the pressure in the auxiliary. In addition, the node of interest with the lowest pressure for a given run will be included in the Flushing Results Browser. If no Nodes of Interest are included, "N/A" will be listed there instead.
Toolbar Buttons on Flushing Results Browser
Flushing Area Report (Flex Table)
While the Flushing Results Browser displays flushing results on an event basis, the flushing area results flex table presents the results on a pipe basis listing whether the pipe met the flushing target and which event was the most effective in flushing that pipe.
With the current scenario set to a flushing output scenario, open the flushing flex table. By default, the table will open with all pipes. If the model is large it is helpful to make a selection of elements and pick "Open on Selection" when opening the flex table.
The user can identify the extent of the drawing that will appear in the optional reports.
Default Report Options
User Defined Report Options
1. Set up the desired background layer
2. Decide the extent of the view to display and if additional views are desired, set up those views.
3. Include detailed notes to help the operators locate the elements (e.g. an operator may not know where H-21 is located but will know "Hydrant in front of 31 Elm St.".
1. Text description of the event indicating which elements to operate
2. Drawing of the event
3. Form which flushing operator can complete to describe results of flushing for feedback (optional).
In addition to the default drawing of the event, the user can create "Secondary Views" which may for example, zoom into details of a complex intersection. To do this, right-click on Report Views in the left pane and select Add Secondary View. Draw a box around the extents of the secondary view and click Select New Report View.
The view that appears when the report is open is called a Preview. With this preview, it is possible to:
The report can be saved and it is possible to zoom and pan within the document.
Example of a Conventional Report
Example of a UDF Operator Report
Export Flushing Area Summary Table
Starting with the CONNECT Edition release of WaterGEMS and WaterCAD, you can now export the Flushing Area Summary Table for a given flushing run. The table is exported into a CSV format, which can be opened in Excel, and will include element labels and results. While the table currently used in the Flushing module allows for the operator to include notes, this export feature allows you to have additional flexibility for presenting your data. Once the data is exported, you can format the Excel file to your specifications.
A crash occurs when duplicating or adding an event, with the following details:
System.InvalidOperationException: Operation is not valid because it results in a reentrant call to the SetCurrentCellAddressCore function.
This is a known issue with version 10.02.01.06 and is resolved by upgrading to version 10.02.02.06 and applying the latest cumulative patch set for version 10.02.02.06 (contact Support for help), or by upgrading to a later version. (when available)
When computing a flushing event, the following error occurs:
Reference to a deleted or inactive element of interest
For the solution, see: Error when running Flushing analysis: Reference to a deleted or inactive element of interest
See: Customizing the Flushing Field Report
Flushing in V8i SS4
Changing the order of Flushing Events or Flushing Areas