Product(s): WaterGEMS, WaterCAD Version(s): 08.11.XX.XX, 10.XX.XX.XX Area: Modeling How does the Pressure Sustaining Valve (PSV) work? Pressure Sustaining Valves (PSVs) throttle (ie. limit or restrict) flow to maintain a user-defined upstream pressure or hydraulic grade. When a PSV is throttling flow: The upstream hydraulic grade and pressure increase. The downstream hydraulic grade and pressure decrease. Situations to use PSVs are useful in situations where unregulated flow would result in inadequate pressures (too low) in the upstream portion of a system. They are also often used to model pressure relief valves. The valve can be in one of three states. Active: Valve is partially opened to maintain the user-defined upstream pressure or hydraulic grade. Inactive: Valve is fully open. Closed Reverse flow through the PSV Reverse flow through a PSV is allowed when the "Status (initial)" is set to Inactive. When the PSV's "Status (initial)" is set to Active, reverse flow is not allowed and "Status (Calculated)" will be set to Closed. Example When the PSV's "Status (Initial)" is set to inactive (ie. fully open): Upstream Pressure = 60psi Upstream Hydraulic Grade = 170ft For: "Setting Type" = Pressure Pressure Setting (Initial) Status (Calculated) 55psi Inactive (1) 65psi Active (2) 80psi Closed (3) (1) If the PSV's "Pressure Setting (Initial)" is below the upstream pressure when "Status (Initial)" is set to inactive, then the "Status (Calculated)" is set to Inactive (ie. fully open) as there is no throttling necessary. This is because even with the PSV fully open, the upstream pressure is already higher than required and any throttling would just increase the pressure more. (2) If the PSV's "Pressure Setting (Initial)" is above the upstream pressure when "Status (Initial)" is set to Inactive, and throttling the PSV will allow the "Pressure Setting (Initial)" to be maintained, then "Status (Calculated)" is set to Active (ie. partially open). (3) If the PSV's upstream pressure can't be raised to the value defined for "Pressure Setting (Initial)", then the "Status (Calculated)" is set to Closed to provide the maximum upstream pressure. Similarly, for: "Setting Type" = Hydraulic grade Hydraulic Grade Setting (Initial) Status (Calculated) 160ft Inactive (4) 175ft Active (5) 200ft Closed (6) (4) If the PSV's "Hydraulic Grade Setting (Initial)" is below the upstream hydraulic grade when "Status (Initial)" is set to inactive, then the "Status (Calculated)" is set to Inactive (ie. fully open) as there is no throttling necessary. This is because even with the PSV fully open, the upstream hydraulic grade is already higher than required and any throttling would just increase the hydraulic grade more. (5) If the PSV's "Hydraulic Grade Setting (Initial)" is above the upstream hydraulic grade when "Status (Initial)" is set to Inactive, and throttling the PSV will allow the "Hydraulic Grade Setting (Initial)" to be maintained, then "Status (Calculated)" is set to Active (ie. partially open). (6) If the PSV's upstream hydraulic grade can't be raised to the value defined for "Hydraulic grade Setting (Initial)", then the "Status (Calculated)" is set to Closed to provide the maximum upstream hydraulic grade. See Also How to model a Combination Pressure Reducing Valve (PRV) and Pressure Sustaining Valve (PSV) Why do I see such a large headloss through my FCV, PSV or PRV?
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Wiki Page: How does the Pressure Sustaining Valve (PSV) work?
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Wiki Page: SewerGEMS For ArcGIS [FAQ]
Product(s): SewerGEMS Version(s): 08.11.XX.XX, 10.XX.XX.XX Area: Modeling How do I open an existing SewerGEMS model inside ArcMap? First, open ArcMap. Then, click the SewerGEMS V8i menu, choose "Project" > Add Existing Project. Select your SewerGEMS model and then click the blue folder icon in the next window, to attach a geodatabase. A separate geodatabase is necessary for ArcMap to interact with the SewerGEMS model. It is recommended that you save a new geodatabase. For example, name it MyModelgdb.mdb and save it in the same folder as your SewerGEMS model. Ensure that you assign the correct coordinate system/spatial reference, before clicking OK in the window that shows the blue folder icon. When you click OK, the Table of Contents will be populated with the SewerGEMS element types and your model should appear. You may need to use the zoom extents button or zoom to an element using the search button at the top of the SewerGEMS properties window. How do I create a new SewerGEMS model inside ArcMap First, open ArcMap. Then, click the SewerGEMS V8i menu, choose "Project" > Add new project. Choose a location to save the SewerGEMS model and then click the blue folder icon in the next window, to attach a geodatabase. A separate geodatabase is necessary for ArcMap to interact with the SewerGEMS model. It is recommended that you save a new geodatabase. For example, name it MyModelgdb.mdb and save it in the same folder as your SewerGEMS model. Ensure that you assign the correct coordinate system/spatial reference, before clicking OK in the window that shows the blue folder icon. When you click OK, the Table of Contents will be populated with the SewerGEMS element types and you can now lay out or import your SewerGEMS model. How can I convert my GIS to a SewerGEMS model inside ArcMap? First, follow the steps above for creating a new SewerGEMS model. Then, use Modelbuilder to import the GIS. Modelbuilder is located under the "Tools" menu inside the SewerGEMS V8i menu. Select ArcGIS geometric network or ArcGIS Geodatabase features as the data source type, select your geodatabase features to import and follow the subsequent steps. Using ModelBuilder to Import External Data What is a Geotable? See: What is a GeoTable? Basically it determines the fields available in ArcMap's attribute tables. Which versions of SewerGEMS support which versions of ArcGIS? See below article: Compatibility Chart Note that versions of ArcMap earlier than the ones listed in this article are also supported. The chart shows the latest available versions that were fully certified. Since the SewerGEMS menus always show up in Arcmap, am I always using a SewerGEMS license? What if I want to use ArcMap without SewerGEMS? As of version 08.11.01.21, SewerGEMS license utilization only occurs when you open a SewerGEMS project (Via SewerGEMS > View > Project manager). For previous versions (08.11.00.08 and below), license utilization will always occur. For information on un-integrating older versions of SewerGEMS with ArcMap, see problem number 35731 in the Knowledgebase. After working on a project in ArcGIS mode and saving a .mxd, why does the SewerGEMS model not appear when reopening the .mxd? After reopening the map, you must first load the SewerGEMS project, under SewerGEMS > View > Project Manager. When working in ArcGIS mode, why are the tools in the SewerGEMS layout toolbar grayed out? First, you must open or create a SewerGEMS model in your current map, using the Bentley SewerGEMS > Project menu. (see further above) Also, you must be in editing mode to use the tools. Go to Editor > Start Editing. How can I enable the flow arrows and active topology colors when working in ArcGIS mode? Go to Bentley SewerGEMS > View > Apply SewerGEMS renderer. What is the easiest way to color code SewerGEMS elements inside the ArcMap platform? Click the element type layer from the table of contents, then click the Bentley SewerGEMS V8 menu, choose Tools > Layer Symbology. This tool will allow you to use the familiar SewerGEMS color coding interface to automatically create ArcMap symbology entries. When annotating or color coding in the ArcMap platform, why aren't all the SewerGEMS attributes available? The attributes available to color code/annotate on are dictated by the attributes included in the geotables. So, click the Bentley SewerGEMS V8 menu > View > Flextables. In the Flextables manager, open the "Geotable" corresponding to the element type in question. Use the yellow 'edit' button to choose the attributes thatwill be available to color code/annotate on. What is the best approach for creating a polyline shapefile or feature class that will be used to build your model using Modelbuilder? How can I convert my GIS data to a water or storm-sewer model inside ArcMap? See Also Product TechNotes and FAQs Haestad Methods Product Tech Notes And FAQs External Links Bentley LEARN Server
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Wiki Page: WaterGEMS V8 Automated Fire Flow [FAQ]
Product(s): WaterGEMS, WaterCAD Version(s): V8 XM, V8i Area: Modeling This is a list of articles containing general FAQs on Automated fire flow for Bentley WaterGEMS and WaterCAD V8i products. To search within this page, press [Ctrl]+F. How does the Automated Fire Flow analysis work? Why do the hydraulic results seen in my junction/pipe table and element properties do not seem to account for fire flow? Why do I see "N/A" for all my nodes in the fireflow report (flextable)? How do I remove the "N/A" entries in the fireflow report for nodes not included in my fireflow nodes selection set? My fire flow report shows fire flow nodes failing due to low pressure at the suction side of a pump. What can I do about this? What is the Fire flow results browser used for? How much pressure is available exactly at the total needed fire flow? Do I need to set the upper limit equal to the needed fire flow? Is there an easier way to check residual pressures at a hydrant for a range of flows? Understanding the "Fire Flow (Needed)" and "Fire Flow (Upper Limit)" Fields for a Fire Flow Analysis See Also Understanding Automated Fire Flow Results Product TechNotes and FAQs Haestad Methods Product Tech Notes And FAQs [[General WaterGEMS V8 FAQ|General WaterGEMS V8 FAQ]] WaterGEMS V8 Modeling FAQ [[WaterGEMS for ArcGIS FAQ|General WaterGEMS for ArcGIS FAQ]] Hydraulics and Hydrology Forum External Links Bentley LEARN Server
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Forum Post: pumps in sewerGems
Hello everybody, I use the Explicit SWMM solver dynamic wave as a solver in SewerGems to model two pumps in parallel. But I see that the solver doesn't account for losses and uses only the last point of the pump curve. My question is to know if is it possible that the solver takes into account the curve of the pumps as input (taken into account the pressure drops) and is not limited only to the last point of the curve?
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Wiki Page: ArcMap .mxd is losing its association with a hydraulic model after moving all project files
Product(s): WaterGEMS, SewerGEMS, HAMMER Version(s): 08.11.XX.XX 10.XX.XX.XX Area: Layout and Data Input Problem When opening a .mxd in ArcGIS/ArcMap that had a WaterGEMS model attached, the model is no longer associated. If the model is added to the .mxd again, then duplicate layers are created. This behavior is common when the files are moved to a new location. Note: This behavior applies to using WaterGEMS, SewerGEMS and HAMMER models in ArcGIS/ArcMap, but for simplicity this article will reference WaterGEMS. Background Basically ArcGIS has historically stored the "absolute" path to data sources in the .mxd. Meaning, when you open a .mxd file, it looks for all the associated layers in the exact original path that they were saved in. This applies to other layers you may have added, not just WaterGEMS layers. So, if you move the .mxd file, WaterGEMS model files, geodatabase, and other layers you had to a new location and try to open it, it won't be able to load any of those layers, because they're referring to the old path. This is why you see red exclamation points next to all the layers in the table of contents. In short, the problems you're having with moving projects are due to ArcGIS limitations, which WaterGEMS has no control over. With that being said, recent versions of ArcGIS have added the ability to use the "relative" path. This way, it will look for the other data sources in the same folder as the .mxd file. In ArcGIS 9.3.1, this option is under File > Document Properties > Data Source Options. In ArcGIS version 10.X, this is under File > Map Document Properties > "store relative pathnames to data sources". So, you would simply need to have this option checked before moving the files to the new location. Solution Here is the full workflow for moving a WaterGEMS for ArcGIS project from one location to another: 1. On the old location/computer, open the .mxd file associated with the WaterGEMS model 2. Go to File > Document Properties and make sure the option to use relative paths is selected. 3. Save the .mxd file and close ArcGIS 4. Move the .mxd, .wtg, .wtg.sqlite, .mdb and any other data sources/layers to the new location/computer 5. Open the .mxd file file on the new computer - it should automatically see the data sources in the same folder as the .mxd and load them. Symbology changes should be retained. See Also WaterGEMS For ArcGIS [FAQ]
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Wiki Page: WaterGEMS For ArcGIS [FAQ]
Product(s): WaterGEMS, HAMMER Version(s): CONNECT Edition, V8i Area: Modeling Create/Open/Save Models How do I create a new WaterGEMS model inside ArcMap? How do I open an existing WaterGEMS model inside ArcMap for the first time? How do I open a WaterGEMS model that is already associated with an ArcGIS MXD file? How do I save my model files when working in the ArcMap environment? ArcMap .mxd is losing its association with a hydraulic model after moving all project files Installation, Compatibility, Integration Which versions of WaterGEMS support which versions of ArcGIS? I've integrated WaterGEMS with ArcGIS and I have the correct versions, but I don't see the WaterGEMS menu. Why? When working in ArcGIS mode, why are the tools in the WaterGEMS layout toolbar grayed out? What is the difference between using the "WaterGEMS for ArcMap" shortcut versus opening ArcMap normally? Data Conversion (ie. import/export) Preparing GIS data for use in the hydraulics and hydrology products How can I convert my GIS data to a water or storm-sewer model inside ArcMap? What is the best procedure to use when creating a shapefile or feature class to help ensure that when I create a model from it using modelbuilder I won't run into problems with pipe or junction connectivity? General What are some operations that I should NOT be performing in WaterGEMs for ArcMap? How do I use and display Active Topology for elements on the ArcGIS/ArcMap Platform? Why a double clicking on element doesn't show the properties for the element inside ArcMap? Geodatabase (.mdb), Geotable, and ArcMap Document File (.mxd) How does the geodatabase (.mdb) file function in WaterGEMS for ArcMap? What is a Geotable? Can I add a field to a WaterGEMS layer without corrupting the feature class or geodatabase? After working on a project in ArcGIS mode and saving an .mxd, why does the WaterGEMS model not appear when reopening the .mxd? Licensing Why is my license listed as "Not Available" under the extensions (Customize > Extensions) in ArcMap? If I'm working in ArcMap without a WaterGEMS model open, am I still using a WaterGEMS license? Element Symbology How do I color code my elements in WaterGEMS for ArcMap? How do I color code different properties on the same layer in WaterGEMS for ArcMap? How do I automatically get my layers in WaterGEMS for ArcMap to populate the WaterGEMS symbology that's in standalone or in the WaterGEMS/CAD for AutoCAD version? How can I enable the flow arrows and active topology colors when working in ArcGIS mode? How do I remove a color coding from a WaterGEMS layer? In WaterGEMS for ArcMap I do not see a dashed line connecting the customer meters to the associated element like I do in WaterGEMS standalone. Why is this? Why aren't all the WaterGEMS properties available when color coding or annotating in ArcGIS? See Also Haestad Product TechNotes And FAQs WaterGEMS and WaterCAD TechNotes and FAQs
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Wiki Page: Model created in older version using an engineering library contains incorrect values in a newer version of the software
Product(s): WaterGEMS, WaterCAD, HAMMER, SewerGEMS, SewerCAD, StormCAD, CivilStorm, PondPack Version(s): CONNECT Edition, V8i Area: Layout and Data Input Problem A model was created in older version of the software using engineering libraries, but when the model is opened in a newer version of the software it contains incorrect component values. For example, this has happened for catch basin inlet throat angles. The inlets were added to the model using an engineering library. That engineering library, originally created in the older version of the software, still contains the correct values when added in the latest version. Solution 1. Go to: Components > Catalog > Engineering Libraries. 2. Add the engineering library that was originally used to add the component. 3. Go to: Components > Catalog > Inlet Catalog (or the catalog corresponding to the incorrect value). 4. Select the inlet, click the Synchronization Options icon at the top, then click Synchronize from Library. (Make sure not to click "Synchronize to library"). Repeat for all inlets used in the model. See Also Modifying and using Engineering Library Data
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Forum Post: Error: An item with the same key has already been added
I am getting this error “An item with the same key has already been added” when changing Scenarios. Particularly after adding additional Nodes after reaching 100 Nodes (even though I have CivilStorm activated)
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Wiki Page: Skelebrator Skeletonizer branch collapsing only updates customer meter associated element fields for the active scenario
Product(s): WaterGEMS, WaterCAD Version(s): CONNECT Edition, V8i Area: Modeling Problem After running the Skelebrator Skeletonizer tool for Branch Collapsing, the customer meters (associated with junctions that were removed) are automatically reassigned to the node that the demands were moved to. However, Skelebrator will only run against the active scenario and won't update the customer meter associated element fields for all scenarios. How can I apply the updated customer meter associated element fields to the other scenarios? Solution It is recommended to skeletonize a model early when you don't have a lot of scenarios. For models with multiple scenarios, skeletonize the base, so that the updated associated elements will be inherited by child scenarios. Running Skelebrator on the base scenario won't update customer meters that don’t inherit properties from the Base scenario. To update other scenarios to match the base scenario's customer meter associated element field, do the following. 1. Run Skelebrator on the Base scenario. 2. Export customer meter labels and associated element labels to a shapefile. 3. Switch to another scenario (that doesn't have the updated associated elements). 4. Use ModelBuilder to import the associated element labels from that shapefile. After you run ModelBuilder the first time, that run is saved to the Modelbuilder Connections Manager dialog. You can switch to another scenario (that doesn't have the updated associated elements), open the ModelBuilder Connections Manager, select that ModelBuilder run, and then click the icon "Sync-In To Model". See Also Exporting model elements to Shapefiles Using ModelBuilder to Import External Data
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Forum Post: RE: Error: An item with the same key has already been added
Hello Kenneth, Please provide the following: The .dgn file. The contents of the text after clicking Details on the error dialog. The application you are using and the version number. See: Sharing Hydraulic Model Files on the Haestad Forum
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Forum Post: RE: Error: An item with the same key has already been added
Hi Craig, I've just uploaded the .dgn, the contents of the text after the error dialog, and the application/version information to the Bentley Secure File Upload site.
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Forum Post: RE: Manhole Headloss HEC-22 3rd Edition
Hello Luis, The headloss calculated by the chosen method is indeed passed to the SWMM engine and used during the SWMM calculations. The headloss through the structure can change as the flow changes, according to the chosen method. This can have an impact on the the upstream flow, for example if the headloss causes the water depth to "back up" (act as a tailwater). The impact would be similar to the impact of increasing pipe roughness, except the loss is concentrated at the structure (the drop in HGL is between the incoming and outgoing side of the structure) instead of across the pipe length. Here is an article explaining the supported Structure Loss Methods for each solver, for each version of the software: Structure Loss methods supported by each solver The Explicit (SWMM) solver in the CONNECT Edition of SewerGEMS supports the Absolute, Standard and HEC-22 3rd edition. This article explains how Bentley has enhanced the SWMM solver to enable such functionality as the HEC-22 3rd edition structure losses: EPA SWMM solver versions used by SewerGEMS and CivilStorm
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Wiki Page: Smart Water Networks
Product(s): WaterGEMS, WaterCAD, HAMMER Version(s): CONNECT Edition, V8i Area: Other Problem How do I incorporate “Smart Water” into my hydraulic model? Background “Smart Water” is a marketing slogan that refers to the ongoing trend to automate more and more of processes in water and wastewater systems and collect a great deal of data. It is a slogan that became popular in the 2010’s and has many definitions. It reflects all of the computerization efforts that have occurred since computers were first introduced into the industry in the 1960’s. Today, hydraulic modelers have access to more data than ever before and the Bentley Hydraulics and Hydrology products are continually adding capability to access that data. The Smart Water Analysis Network defines Smart Water as, “There are a lot of varying definitions out there, but we define smart water as a group of emerging technology solutions that help water managers operate more effectively. These solutions harness state-of-the-art hardware and software to provide increasing levels of system intelligence, visibility, automation and control, and customer service.” Bentley Systems also has an e-book outlining the recent trends in Smart Water technology GIS Data GIS data is often used to build hydraulic models with ease. But the usage of this data is limited to the modeling or planning stage and is absent during the operational and maintenance period. The GIS data-set can store intelligent information such as asset life cycle, cost, operational history etc. for the hydraulic elements modeled which can be useful in making “smart” decisions. E.g. Pump operational history, life, make etc. information can be stored as attributes which can be imported into the hydraulic model. This information can then be used to simulate “What If?” scenarios for various pump operations. SCADA Data Connecting a SCADA system to a hydraulic model is a great example of making “smart” decisions and eventually “smart” utilities. The SCADA system can provide real time inputs to the hydraulic model such as flow and pressures which can be used as data for predictive analysis of the network under simulated conditions. SCADAConnect Simulator is an existing tool within WaterGEMS which can incorporate real time data by communicating with the SCADA server and report the values once configured. 3-D Visualization 3-D visualization of utilities has become imperative to generate layouts. The Subsurface Utility Design and Engineering is a module available on the MicroStation® Platform. Using this we can model utilities in the 3-D environment to understand the physical and functional considerations. This can also help in clash detection and optimization of network layouts. Asset Management To develop a smart model, management of assets is imperative. Asset management involves incorporating field or on-site data regarding assets and analyzing it to develop methodologies to reduce cost, optimize workflow and increase productivity. Bentley’s AssetWise has a host of solutions for monitoring, analyzing, predicting and dashboarding asset information and functionality. Cloud Cloud storage and computing are the next generation in data handling. This is a great tool to conveniently store intelligent information and access it with ease. With multiple “smart” engines collaborating with the hydraulic model, this can be a reliable resource. We continue to work on solutions to leverage the cloud with your Bentley Haestad hydraulic modeling software. Check back for more information on this subject in late 2018. Automation Automation of routine activities is a logical trend which can be effectively implemented to automate routine activities for the network. Automation can be effectively used to automatically track changes in pressure and flow and follow the prescribed decision matrix (pre-configured) to make changes in the network. This can be as simple as the closing of a valve to isolate part of a network. Your hydraulic model can be used to check the impact of these actions, to help develop these routines. Automatic Meter Reading (AMR)/Advanced Metering Infrastructure are more popular these days where AMR replacing the human component of meter reading with remote access and control. Primarily, AMR is used for reading data beneficial to billing cycles. AMI on the other hand is a more complex and powerful tool which measures hourly data in real time and can be configured for reader feedback. IOT is yet another emerging technology which focuses on capturing data for analysis. The performance of a pump can be tracked in real time by collecting important data. Operation & Maintenance Considering the future performance of a water supply or any other utility, operation and regular maintenance has become imperative in today’s world. A hydraulic network can be very useful in understanding the operation and maintenance requirements throughout the design period. Often there is need of upgradation or replacement of components. By integrating the hydraulic model with operation and maintenance schedules one can prepare the hydraulic model to incorporate changes by following “smart” decisions. Tools in WaterGEMS Some other existing tools in WaterGEMS which can help develop “smart” utilities; 1. Darwin Designer – Optimize networks based on cost, pressure and pipe size. 2. Darwin Calibrator – Calibrate models as per field data. Helps improve model accuracy. 3. Darwin Scheduler – Optimize pump operations and schedules for a time horizon. 4. Pipe Renewal Planner – Scores pipes based on breaks, criticality and capacity. 5. Pipe Break Analysis – Analyzes historical pipe break data to score pipes. Can be incorporated into the asset maintenance of pipes. 6. Criticality – Analyze your model to identify critical segment and outage events. See Also Using Darwin Designer to design pipes in WaterGEMS Using Darwin Calibrator Using Darwin Scheduler SCADAConnect Simulator for WaterGEMS Understanding Haestad Hydraulics and Hydrology Functionality in Subsurface Utilities / OpenRoads
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Forum Post: RE: pumps in sewerGems
Hello Julia, The pump operation follows the pump curve setup in the pump definition. How are the parallel pumps set up? Pumps in parallel should have the same curve so as to work in parallel. What pump definition are you using? If you can share a snapshot of how you have set up your pumps in parallel it would help us understand the operation. Hope this helps.
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Wiki Page: Modeling Grinder Pumps
Product(s): SewerGEMS, SewerCAD Version(s): 10.XX.XX.XX, 08.11.XX.XX Area: Modeling Overview This tech-note discusses how to configure grinder pumps while modeling a pressure sewer system. Background A grinder pump is generally used to convey sewage from the source (typically a house connection) to sewer main. Typically, this pump system consists of a sump/storage well, the pump itself and an instrument panel. The function of the “grinder” pump is to pump wastewater from the customer’s sump into the pressure sewer system and grind solids to that they will not clog sewers. Generally, these pumps are installed for individual houses or commercial buildings connecting to a common sewer main. In a locality such grinder pumps are useful in conveyance of sewage to the main sewer which would ultimately terminate at the treatment plant. There are two general categories of grinder pumps: 1. Semi-positive displacement pumps characterized by the E/One style pumps and 2. Small centrifugal pumps manufactured by numerous companies. Solution For this tech-note we are considering the “E/One” grinder pumps commonly used in designing sewerage networks for localities. The “E/One” grinder pumps work on the “E/One Probability Method” which provides data to run the pumps simultaneously. The E/One pumps have a near vertical Head vs. Discharge curve which enables them to run over multiple points of operation. This ensures that multiple pumps can run simultaneously efficiently over a range of discharges. Grinder pumps may be either positive displacement or centrifugal type. The E/One grinder pumps are semi-positive displacement pumps which discharge whatever their design flow is without much dependence on pressure whereas centrifugal pumps operate on their defined pump curve. For centrifugal pumps, the user can assign a flow, HGL or an effective pump curve for each node. The effective pump curve approach is the most accurate. Obtain a typical pump curve and combine it as you would for any other pumps in parallel, i.e. keep the same head values and multiply flow by the number of running pumps. For E/One pumps or those using similar technology, the E/One Probability Method provides a table defining the maximum number of grinder pumps operating daily (Table 3, Low Pressure Sewer Systems Using Environment One Grinder Pumps). To model multiple grinder pumps in a sewer system the above table needs to be converted into an Extreme Flow Table which will govern the flows in the sewer system. Converting Data to Extreme Flows Table The Extreme Flows Factors can be used with the GVF-Convex Solver available in SewerGEMS and SewerCAD. Note: If dynamic solvers (Implicit and Explicit) are used to design the pressure sewer system, the user has to set up inflow hydrographs for each of the nodes and then define them in SewerGEMS (which has both the dynamic solvers). From the above Table 3, the values of number of cores connected and maximum daily running cores are extracted and analyzed to develop the extreme flow factors. No. of grinder pump cores connected Max. number of pumps operating simultaneously Min Max 0 1 1 2 3 2 4 9 3 10 18 4 The above table is just an expanded form of Table 3 to simplify the understanding of the maximum simultaneous operation of pumps; No. of Pumps No. of maximum simultaneous operating pumps Extreme Flow Factor (Col2/Col3) 1 1 1 2 2 1 3 2 0.67 4 2 0.75 No. of Pumps No. of maximum simultaneous operating pumps Extreme Flow Factor (Col2/Col3) 1 1 1 2 2 1 3 2 0.67 4 2 0.75 E.g.: As per Table 3, for 4 pumps set up on field a maximum of 2 pumps can be operating simultaneously. Hence the extreme flow factor is 2/4 = 0.5 The above table can be expanded to include all the ranges provided in Table 3. This table can be setup as an extreme flow method which the software will follow to decrease the peak flow as flow moves downstream. The table can be prepared in Excel and copied in the Extreme Flow Setup. Alternatively, it can be converted into an equation. We have already done this in our book "Wastewater Collection System Modeling and Design" on pages 474 and 475. The coefficients for the equation depend on things like flow per pump and people per pump. Using a table to define the extreme flows is preferred as there is no limit on the number of pumps that can be configured. This means that the computed flows from SewerGEMS/SewerCAD will always match the flow calculated by the E/One Probability Method. On the other hand, if the equation is used you may get some fluctuations in values as they do not conform to a continuous function. Setting up the model For the extreme flow setup to function, the system must be modeled as a gravity system with bolted manholes rather than a pressure sewer system with pump elements representing the grinder pumps. In pumping hydraulics, the pressure solver computes the flows in the system based on actual flows which may exaggerate the downstream flows and may not conform to the extreme flow setup. If the system is designed as a gravity system with bolted manholes, when the system is surcharged, there won’t be overflow due to the bolting and the conduits would behave as pressure pipes simulating a pressure sewer system. Setting up the grinder pumps For a small locality there might be hundreds or thousands of houses and it will be practically time consuming to model hundred to thousand individual pump elements based on the H vs. Q provided in the E/One Manual. In SewerGEMS/CAD the number of contributing grinder pumps can be set up as “Loading Unit Count” for a manhole. E.g. Suppose 5 houses having 5 grinder pumps respectively, are contributing or connecting to a common manhole (of the trunk/main sewer line), then the “Loading Unit Count” at that manhole can be 5. Based on the type of grinder pump selected the “Unit Load” can be kept as 15 or 11 gpm which is as per the E/One Design Manual. The E/One Manual assumes fixed flow for the pumps, but the user can define the pumps as per the project requirements. Note: The method described above works well for the GVF-Convex Solver. If dynamic solvers (Implicit & Explicit) are used, the results might be unstable. In such a case, the user would have to develop inflow hydrographs for each of the nodes and define them in SewerGEMS (which uses both these solvers). Response to Power Outage One of the worst cases for a pressure sewer system occurs immediately after an extended power outage. In this situation, when the power is restored, most sumps will be full and many (if not all) of the pumps will start simultaneously. This can result in very high pressures. It is worthwhile to check the pressures during this situation although it is usually not necessary to size pipes to carry all the flow through all the pumps simultaneously. FAQ’s 1. In the absence of a pump element how will be sewage flow in the system? The HGL at the manhole will be as per the loading defined for that manhole. 2. How to find the pump head at the manhole? To get the HGL at which the pump is delivering (pump head), the suction head needs to be subtracted from the HGL developed after analysis. 3. Does the loading count have to be “lots”? Can “population” be used? For the particular E/One Probability Method, the pump cores/lots serving a manhole is considered as “Loading Unit Count”. Population can be used when you don’t know the number of grinder pumps connecting to the manhole. Sample Model The sample model available at this link contains a model setup using the extreme flows setup. Supporting files contain the extreme flow factors in excel and the E/One Design Manual. See Also Forum Discussion Using Extreme Flow Factors Wastewater Collection System Modeling and Design
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Wiki Page: Which Pump Definition Types can be used by the GVF-Convex, Implicit and Explicit solvers?
Product(s): SewerGEMS, CivilStorm, SewerCAD Version(s): 08.11.XX.XX and 10.XX.XX.XX Area: Calculations Problem Which Pump Definition Types can be used by each solver? Solution There are many types of pump definitions in Bentley storm and sanitary sewer models. These pump definitions are established by going to Components > Pump Definitions. These definitions can be assigned to any pump element. Pump definitions contain the pump curves describing pump performance. The only curve that is mandatory for modeling a pump is the head curve. Efficiency and motor curves are only used in Bentley water models. Some of the definitions are used only in the implicit and explicit dynamic wave solvers while others are only used in the pressure portion of the GVF-convex solver. The only definition type that is common to all solvers is the Multipoint pump head curve. The chart below shows which Pump Definition Types are available for each of the solvers. Pump Definition Type GVF-Convex Implicit Explicit Constant Power YES NO NO Custom Extended YES NO NO Depth - Flow (Variable Speed) NO YES YES Depth vs. Flow (Type 2) NO YES YES Design Point 1 Point YES NO NO Multiple Point (Type 3) YES YES YES Standard 3 Point YES NO NO Standard Extended YES NO NO Volume vs. Flow (Type 1) NO YES YES See Also Differences between solvers: GVF-Convex vs. GVF-Rational vs. Implicit vs. Explicit (SWMM) Help Topic "Pumps"
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Forum Post: Negative pressure in system due to D2A element (Hammer/WaterGems)
I have a system (shown below in Option 1) which consists of two pumps (1 working + 1 standby) which is supplying water to three tanks. The pump is considered to be VSP type, with a target flow of 575 m3/hr. The demand at D2A-1, D2A-2 & D2A-3 are 101 m3/hr, 373 m3/hr and 101 m3/hr respectively. I have to carry out surge analysis for the system. To make things simpler, I have considered three D2A elements (orifice type) in place of the tanks. However while computing the intitial conditions I get a notification regarding negative pressure in the system stating "Negative pressures in system at one or more time steps." After referring to the profile of HGL and elevations, I found that the HGL at D2A-2 and D2A-3 goes below the physical elevation at the respective D2A. Moreover, the flow supplied is coming out to be 1265 m3/hr inspite of setting the target flow to 575 m3/hr. I tried increasing the head of the pumps keeping the pump discharge constant, but that didnt help as well. I created another model (shown below in Option-2) where I replaced the D2A with tanks and then assigned a D2A at the outlet of each tank. I assigned the respective demands at each D2A from the outlet of tanks. After computing the model, the model did not render any warnings. So why were there negative pressures in the system while I was using D2A in place of the tanks?
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Forum Post: RE: pumps in sewerGems
Hello Yashodhan, I use the pump definition type : multiple point (type 3). The two pumps don't have the same starting and stopping levels. Here are the parameters of each pumps. They don't have the same pump curve. Thanks
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Wiki Page: Creating Formula-Based User Data Extensions
Product(s): WaterGEMS, WaterCAD, StormCAD, SewerCAD, SewerGEMS, CivilStorm, HAMMER, PondPack Version(s): CONNECT Edition, V8i SELECTseries 2 + Area: Calculations Overview The purpose of this technote is to briefly review the methodology for setting up a formula-derived User Data Extension, also known as Formula UDX. Additional information can be found in the Help section for the program. Background User Data Extensions (UDX) have been a feature available in the water and waste water products for some time. With the release of SELECTseries 2 builds of the software, a new 'Formula' ability was added to give extra flexibility to the user. This feature will allow the user to calculate results that the programs might not otherwise generate and display these results in the element properties or FlexTables. NOTE : a formula-derived user data extension currently only evaluates at a given time step. Meaning, you currently cannot perform functions against time-series data, such as the maximum, minimum or average value of a result field over the simulation duration. General Information on User Data Extensions User Data Extensions allow the user to create new fields for use in reporting, graphing, or data analysis. For example, you can add a field for keeping track of the date of installation for an element or the type of area serviced by a particular element. The UDX dialog can be accessed directly by going to Tools > User Data Extensions. Selecting this will open the User Data Extension dialog. There are a number of data types available. These include integers, real (or any fraction decimal number), text, date/time, boolean (true or false), and formula. There is a label field to allow the user to give the UDX a unique name so that it can be easily viewed in the element properties or FlexTables. With real and formula UDX fields, the user must also enter Dimension, Storage Unit, and Numeric Formatter. To create a UDX, highlight the element and select the New icon. The section on the right will fill in with default data. As this technote is related to formula-based User Data Extensions, change the Data Type to “Real (Formula)”. When this is completed, the Units section will appear. Enter the appropriate Dimension, Storage Unit, and Numeric Formatter for analysis you will be conducting. You should also change the label to something recognizable for the analysis. Once you have done, select Okay. Note: Once you select Okay, some fields, such as Data Type, Dimension, and Storage Unit, cannot be changed or edited. The formula itself can still be edited though. Formula-based User Data Extensions Bentley's Hydraulics and Hydrology products give a wide range of results that are generated after the computing a model. In most cases, these results are sufficient for analyzing and reporting on a system. However, there are times when a user may want to see a set of results that are not available in the program. It was for cases like this that the formula-based User Data Extension was developed. Note: You cannot create a formula that uses properties from more than one element type, and the results of a formula UDX are only evaluated at a given timestep (you currently cannot find the max/min/average for example, of a result over time) The formula-based UDX allow the user to generate new results based on the data already calculated after computing the model. The basic steps below are universal, with only the element types and available properties differing depending on the product. The example below will be using WaterGEMS. Let us say that you want to display the percentage of pressure head compared with the calculated hydraulic grade for the junctions in a WaterGEMS model. To begin, open the User Data Extension dialog. Create a new UDX by selecting the New icon at the top of the dialog. Change the label to something recognizable to these results and change the Data Type to “Real (Formula)”. Since the result will be a percentage, change the Dimension field to “Percent”, the Storage Unit to “%”, and Numeric Formatter to “Percent”. Next, click in the Formula cell. An ellipsis (...) will appear. Click this to open the Formula dialog. In the upper left is a list of all available properties for the junctions. The list is in alphabetical order. The same properties are accessible through the “>” icon above the list. In the upper right are all of the mathematical functions available. The empty window in the lower part for the dialog is where the formula is built. To move a property to the lower window, simply double-click the name. It will then appear in the window. Note that the appearance is not the same as the property list; the window shows the Access database table name for that property. To include a simple math function, like multiplication or subtraction, click the corresponding button. For the geometric or trigonometric math functions, double-click the name to include in the formula. In the example where we want the percentage of the pressure head compared with the calculated hydraulic grade, first select the “(“ icon. Next, find “Pressure Head (ft)” in the properties list and double-click. Next choose the divide icon, then the “Hydraulic Grade (ft)” property, and then the “)” icon. Since we want this as a percent multiply this by 100. Once completed, select 'OK' to return to the User Data Extension dialog. Click 'OK' again to save the UDX. *Note: Many features, including the Data Type, Dimension, and Storage Unit, cannot be changed or edited after selecting 'OK'. Viewing Results Since the results are saved as user data extensions, you can view the results in either the element properties or the FlexTables. After computing the model, double click on a junction to open the Properties dialog. Find the “User Defined” section. This is where the formula UDX field will be located and, since the model was computed, you should see the results. To see the results in the FlexTables, open the element FlexTable (View > FlexTables, for instance). With the FlexTable open, select the Edit icon. Scroll through the list on the left to find the UDX field. The list is in alphabetical order. Select the 'Add' button and it now appears in the list on the right. Click 'OK' to return to the FlexTable. The statistical analysis results should now be available. This data is also available for results presentation in graphs and data tables. You will also be able to created color coding and annotation through Element Symbology once the User Data Extension is created. Exporting UDX If you want to use the User Data Extensions that you have created, you can export them to a .XML file for use in another model. To do this, click the Export to XML button in the upper left. This will allow you to save the UDX as an .XML file for later use. To add the exported UDX's into a new model, open the User Extension Manager in the new model. Then click the Import button in the upper left and browse to the .XML file with the User Data Extensions you wish to use. The UDX's will then appear in the model for use. Video demonstration www.youtube.com/watch See Also Wiki: How do you create an IF / THEN / ELSE statements using Formula derived user data extensions? Can a user data extension with an IF, THEN, ELSE (iif) statement assign a value to another field? User Data Extensions in the Fireflow report Add custom data to profile with User Data Extensions How is the “max” operator used with formula-derived user data extensions? User data extension fields are not showing up in the section they were created in and cannot be graphed. Blog: Creating Custom Calculated Results with Formula User Data Extensions
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Wiki Page: PondPack TechNotes and FAQs
This article provides a list of in-depth TechNotes and FAQs for Bentley PondPack. To search within this page, press [Ctrl]+F. Frequently Asked Questions PondPack General FAQs Moving from V9/V10 to V8i FAQs Modeling Creating formula-based User Data Extensions Entering Underground Storage Chamber Information Understanding the Modified Rational Method Using PondMaker Using The Network Navigator What's new What's new in PondPack CONNECT Edition? See Also PondPack Product Information Haestad Product TechNotes And FAQs Haestad Methods Water Solutions on Bentley Website Bentley Application Support Policy for PondPack, FlowMaster and CulvertMaster
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