Product(s): WaterGEMS, WaterCAD, SewerGEMS, SewerCAD, CivilStorm Version(s): 08.11.04.xx and later, 10.xx.xx.xx Area: Modeling Overview This article explains how to use the Scenario Energy Cost and Energy Management tools. The images in this article were taken from WaterGEMS, however the same general workflow applies to all products listed below. The Scenario Energy Cost tool is available in: WaterGEMS and WaterCAD SELECTseries 4 (08.11.04.xx) and later SewerGEMS, CivilStorm, SewerCAD CONNECT Edition (10.00.00.40) and later The Energy Management tool is available in: WaterGEMS and WaterCAD SELECTseries 4 (08.11.04.xx and later) Not available in SewerGEMS, CivilStorm, SewerCAD Table of Contents Background Scenario Energy Cost Analysis Energy Pricing (Tariff Types) Time of Day Block Rate Block Rate Based on Billing Demand Constant Viewing Results Water Power, Wire Power, and Wire to Water Efficiency Multiple Peak Charges in Energy Management Turbine Energy Recovery Modeling Energy Management Power Meters Carbon Emission Analysis Background There are two levels at which energy costs can be analyzed in the software. The tool called "Scenario Energy Cost" calculates energy use and cost for a single scenario. This tool is available in WaterGEMS, WaterCAD, and SewerCAD. "Energy Management" uses the results of multiple Energy Cost scenarios to determine energy costs at a higher level of aggregation to determine the energy cost for pump stations (not just pump-by-pump) for multiple scenarios that can occur over a billing period and determine economic costs such as net present worth of pumping energy. This tool is available in only WaterGEMS and WaterCAD. The Scenario Energy Cost analysis determines the energy cost by pump for all pumps selected by the user. Pricing for energy cost is set up in the Pricing button in energy costing. Price functions are assigned to individual pumps in energy costing. For users interested in a more complete energy analysis, running a single scenario may not be sufficient as block rate charges must be determined based on energy use over a complete billing cycle which may contain low, average and high water use periods which should be modeled as separate scenarios. In addition, the scenario corresponding to the setting of a peak demand charge is usually not an average day but some kind of peak condition that should be modeled in a separate scenario. In order to deal with the complexities of block rates, multiple scenarios, aggregation of pumps within a station, and performing present worth calculation, the user needs to use the Energy Management analysis. Such calculations are usually required because of complex tariffs for electric power. Because there may be other energy uses at the pump station besides pumping, the user can specify non-pumping energy costs to account four uses such as lighting, HVAC, control systems, chemical feed equipment, etc. These costs are added in on a Power Meter basis. There may also be charges on the power bill that are not associated with individual pumping operations such as taxes, discounts, lump sum surcharges, etc. These can be added in to the overall cost and are referred to as "other costs". The usual work flow for using the energy cost and energy management analyses may be followed as shown below: Develop EPS scenarios to be used in energy cost. Run scenarios. Start scenario energy cost analysis. Create price functions and optional carbon emission factors. Assign price functions to pumps. Run energy cost for each scenario of interest. In WaterGEMS/WaterCAD, the user can also conduct a more thorough analysis using the following steps: Close scenario energy cost analysis and start energy management. Create new energy management study. Identify which pump stations/pumps are associated with each power meter. Specify the mix of scenarios to be analyzed. Identify interest rate and number of periods if present worth calculations needed. Compute study. Review results and rerun or create new studies. In the next section we will go through a detailed step by step guide of how to use the Energy Management and Scenario Energy Cost tools. Scenario Energy Cost Analysis To open the Scenario Energy Cost tool in WaterGEMS/WaterCAD Connect Edition, go to Analysis > Energy Cost > Scenario Energy Cost. In WaterGEMS/WaterCAD V8i, the Scenario Energy Cost tool can be opened by going to Analysis > Scenario Energy Cost, or by selecting the Scenario Energy Cost icon in the toolbar. For SewerCAD CONNECT Edition, you would choose Analysis > Energy Cost. This will open the Scenario Energy Cost manager as shown below. On the left side of the manager, it will display the current scenario. If you wish to analyze a different scenario, you can choose it from the Scenario pulldown. Note: The Scenario must be an EPS run. The right side of the manager is where you will set up the energy cost analysis. On the left side of the manager you will see some result fields and specific element options. You can specify which elements will be included in the analysis in the table located on the bottom left of the manager. After selecting the scenario you will be analyzing, you will need to set up the energy pricing. To do this, click in a cell in the Energy Pricing column and click the ellipsis ("...") button. This will open the Energy Pricing manager. There are four types of Energy Pricing. Time of Day Block Rate Block Rate based on Billing Demand Constant Each of these types of Energy Pricing will act differently when you run an Energy Analysis. The Time of Day Energy Pricing will calculate energy cost comparing hours vs. $/kwh. Note: You can change the units for the energy pricing by right-clicking on the current units and choose "Units and Formatting." This allows you to change the units and the precision that the data is displayed. Time of Day The Time of Day Energy Pricing will calculate energy cost comparing hours vs. $/kwh. Energy Supply Rate structure based on a Time of Day Pattern. To create a new Time of Day Energy Pricing definition, click the New icon in the upper left. On the right side of the manager is where the data is entered. The energy pricing data itself is entered in the lower right of the dialog. First, change the Tariff Type to Time of Day. Then enter the “Starting Energy Price.” If the pricing changes over the course of the EPS run, you can enter that data in the table below "Starting Energy Price." If the pricing will include Peak Demand Charge, you must place a checkmark in the box beside “Include Peak Demand Charges?” When this is done, the two fields used with this will become available. Enter the value for Peak Demand Charge and Billing Period. The Billing Period is used to convert the peak demand charge, which may be calculated for the month, year, or another period of time, into a daily cost which can be added to the energy cost to obtain the Daily Cost. Block Rate Block Rate Energy Pricing will calculate energy cost based on a Block Rate Cost Structure. A Block Rate is a certain price charged for the first definite number of units used and a successively lower or higher price for each additional block used. Block rate charges must be determined based on energy use over a complete billing cycle which may contain low, average and high water use periods which should be modeled as separate scenarios. Note: Block Rate cannot work during Energy Scenario Cost Analysis because it must be determined based on Energy use for a complete billing cycle. Block Rate Energy Prices can only be calculated using the Energy Management tool. Block Rate Energy Pricing will compare Energy Use (kWh) vs. Energy Price ($/kWh) Block Rate based on Billing Demand Block Rate Energy Pricing will calculate energy cost based on a Block Rate Cost Structure. A Block Rate is a certain price charged for the first definite number of units used and a successively lower or higher price for each additional block used. Block Rate Energy Pricing will compare Energy Use per Billing Demand (kWh) vs. Energy Price ($/kWh) Note: Block Rate Energy Prices can only be calculated using the Energy Management tool. Constant Constant Energy Pricing will use a constant Energy Price ($/kWh) for the entire model simulation. If the pricing will include Peak Demand Charge, you must place a checkmark in the box beside “Include Peak Demand Charges?” When this is done, the two fields used with this will become available. Enter the value for Peak Demand Charge and Billing Period. The Billing Period is used to convert the peak demand charge, which may be calculated for the month, year, or another period of time, into a daily cost which can be added to the energy cost to obtain the Daily Cost. Click "Close" to return to the Scenario Energy Costs manager. When you click a cell in the Energy Price column, the energy price definition that was created will be available for selection. Viewing Results Once the energy pricing and the elements to be used in the analysis are selected, the analysis can be run. Note : You must compute the scenario before you can calculate the energy cost. Click the Compute icon in the upper left of the Energy Cost manager. Once completed, the pumps for which the calculation was run will appear in the window on the left side of the dialog. To view the results for an individual pump, select one of them from the window on the left. A Results table will appear on the right side of the manager. You can also view the available results fields as a graph by selecting the Graph tab. To select which result field to view, click the pulldown and select the field. Depending on the item you highlight different results are available. For instance, if you click on the top-most item in the tree, you will see a summary of results that include information on the energy used, the cost, the volume of flow, and the run duration. The Pump/Turbine Usage (or Pump Usage for SELECTSeries 6) folder includes this same information, but broken down by the pumps, VSPBs, or turbines that are in the model. The Pump Time Details folder shows the combined results such as volume, flow, wire power, energy cost and energy usage for all pumps over time. There is also a graph tab that allows you to view these results in a graphical format. You will also be able to view these results, plus results for water power, motor efficiency, wire to water efficiency, and cost per unit volume. As with the Pump Time Details, this shows the results per time steps. The results can also be graphed. Tank costs are accounted for in the Storage item. Peak Energy Demands shows when the peak occurs and any costs that are associated with that. Water Power, Wire Power, and Wire to Water Efficiency Many of the results that the Scenario Energy Cost manager generates are relatively straight forward. As an example, Volume Pumped (Incremental) is the volume pumped during that time step. For a few results, such as water power, wire power, and wire to water efficiency, some additional information may be needed. Water power is the amount of energy transferred to the water by the pump. This is related to the flow rate and the head added by the pump, in addition to the specific weight of the liquid (typically water). The equation used is: Wire power is the amount of energy delivered to the pump motor. Information below will show how this is derived in the program Wire to water efficiency is the ratio of water power to wire power. This can found by taking the dividing the water power by the wire power. It can also be determined by multiplying the pump efficiency and the motor efficiency. In addition to the items above, two other properties are important in the calculation of the energy used by the pump. This is the pump efficiency and the motor efficiency . Pump efficiency is derived based on the efficiency data you enter in the pump definition. You can choose to energy a Best Efficiency Point, Constant Efficiency, or Multiple Efficiency Points. Best Efficiency Power generates a curve based on the BEP Efficiency and the flow that the best efficiency occurs. Multiple Efficiency Points allows the user to enter the efficiency for different flow values. Constant Efficiency is a single efficiency value for all flows. Best Efficiency Point or Multiple Efficiency Points would likely yield the best results. Motor efficiency is also added in the pump definition under the Motor tab. It is a value set by the user. Putting it all together The energy results are determined using the wire power. In WaterGEMS and WaterCAD, the wire power is calculated by first finding the water power using the equation above. Once the water power is determined, this value is used to find the brake power using the equation: where WP is the water power and ep is the pump efficiency at the given flow that the pump is pumping at. Once the brake power is calculated, this is used to find the wire power using the following equation: where IP is the wire power and em is the motor efficiency. With the wire power, the energy used by the pump can be calculated by multiplying the wire power and the time for the energy cost simulation. Multiple Peak Charges in Energy Management The software can also be used to manage tariffs with multiple peak charges. Availability: WaterGEMS and WaterCAD V8i SELECTseries 4 (08.11.04.xx) and later Not available in SewerGEMS, SewerCAD, CivilStorm After placing a checkmark in the box, the user can now edit the multiple peak changes. The Peak Charge Type can either be based on Clock Time or Simulation Time. The user will include the start and end times for the peak charge and enter the value for the peak demand change. With this data entered, multiple peak charges can now be taken into account when running the Scenario Energy Cost simulation. For information and assumptions on multiple peak charges, see the below Support Solution: Using Multiple Peak Demand Charges Turbine Energy Recovery Modeling Starting with the CONNECT Edition release of WaterGEMS and WaterCAD, it is now possible to model turbines for energy and revenue generation using the Scenario Energy Cost module. Turbines are more often used in HAMMER's transient analysis because of potential transient impact of startup and shutdown, however they can also be modeled in WaterGEMS and WaterCAD as well. The general setup for turbines will be the same as for pumps. In the Scenario Energy Cost manager in WaterGEMS/WaterCAD CONNECT Edition, you will now see a Turbine tab. As with pumps and pump stations, you will select Energy Pricing and, if applicable, Unit Carbon Emissions. The pricing data you use may be the same as the pump pricing data, depending on the setup of your system. One key takeaway is that turbines are typically used for energy generation . For this reason, the energy data in the turbine energy results is the energy generated, and the cost information is the revenue from the turbine. If you consider a case like the screenshot below, there is a pump and turbine in parallel. The setup of the model is such that the pump will be filling a downstream tank until the tank is full. The tank will then drain, passing through the turbine back to the reservoir upstream of the pump. The purpose of passing through the turbine is so that energy is generated as water flows into the reservoir. In running the scenario energy cost analysis for this system, you can see that some of the cost for running the pump is recouped by having the turbine in place. The energy cost data in the summary table above is a negative value because energy is being generated by the turbine. This allows you to see the net cost that includes the cost of running the pump and the revenue generated by the turbine. Note that turbines are not included in the Energy Management tool, which is discussed below, at this time. Energy Management The Scenario Energy Cost Manager is ideal for comparing different scenarios based on energy cost. However, if you would like to do more thorough analysis of Block Rates, Multiple Scenarios, or would like to consider all Energy Use you should open Energy Management tool. Note that this tool is not available in SewerCAD at this time. The Energy Management tool will allow you to use Block Rates and compare Multiple Scenarios using a single tool. You will also be able to add other Energy Costs that are not associated with WaterGEMS/WaterCAD elements such as Lighting, HVAC, Taxes, etc. Below is a list of the main differences between running the Scenario Energy Cost vs. Energy Management: Scenario Energy Costs Energy Management Detailed Energy Use Results Summary of Energy Costs Single Scenario One or More Scenarios Cost by Individual Elements and System Wide Cost by Individual Elements, Power Meter, Scenario and Systemwide Pumps and VSPB’s and Tanks Pump Stations, Pumps, and VSPB’s Cost based on Unit Energy cost or Time of Day and Peak Demand charge Cost based on all types of Energy Tariffs including Block Rates and all those from Scenario Energy Cost Considers Pump Energy and Demand Considers All Energy Use Considers only Energy Costs Considers Pump, Non-Pump and Extraneous costs To open an Energy Management Study in WaterGEMS/WaterCAD CONNECT Edition, go to Analysis > Energy Cost > Energy Management In WaterGEMS/WaterCAD V8i, click on the Energy Management icon or go to Analysis > Energy Management. Once you open the Energy Management dialog you will see the following window appear. Click the New button in the top Left Corner to create a New Energy Management study. Once you create a New Energy Management Study you will see multiple Tabs to enter data. The first Data Tab is the Options tab. Here you are able to set the Billing Period, Calculate Net Present Value, and Scenario Data. The most useful part of using the Energy Management tool is the ability to compare scenarios in the same study. As shown below you can add and compare Scenarios based on Percentage of Billing Period. The model uses the Billing Period value entered to calculate the Total cost of the study. Billing Period - Enter the total Billing Period for the Energy Study. EX. (730 days - 2 years) Calculate Net Present Value - Check to calculate the Net Present Value using the Interest Rate and Number of Years variables. Scenarios Table - Add all of the scenarios you would like to compare in a single Energy Management Study. In this example, Average Day and Peak Day scenarios are included. Include in Cost Calculation - Check Box to include or exclude the Scenario from the Management Study. Percent of Billing Period - Percentage of Billing Period entered above to use the specified scenario for the Energy Management Calculation. Compute Scenario and Energy - Dropdown menu where you can select whether to recompute the Hydraulic model Data as well as recompute the Scenario Energy Cost. (Note: Leaving this as "None" will save Calculation Time.) Use for Peak - Check Box to use the specified Scenario for Peak Demand Charge. Power Meters An important concept in energy management analysis is that of a "Power meter". A Power Meter is the basic unit that is billed by an electric utility. A Power Meter usually corresponds to a pump station. However, in WaterGEMS/WaterCAD, a pump station is a collection of pumps serving a single pressure zone. Therefore, if a pump station building has a single electric service but has a set of Low, Medium and High service pumps, for WaterGEMS and WaterCAD hydraulic calculations, it is three Pump Station elements but for energy management, it corresponds to a single Power Meter. The figure below shows how a single power meter can include multiple pumps and pump stations in a single building. Power meters are used during Energy Management. To enter data for a Power meter click on the Power meter Icon on the main toolbar inside the Energy Management dialog box. The Power Meter Dialog box looks like the following. There are Tabs to enter Pump Data, Non-Pumping Energy, and Notes. To create a New Power Meter click on the New button in the top left corner of the Power Meter window. Pumps Tab - Enter the Pumps corresponding to the specified Power Meter. Non-Pumping Energy - Enter other cost data associated with the Power Meter such as HVAC, Lighting, Control Panels, Security Systems, Temperature Control Systems, or any other Extraneous data. Notes - Enter any Notes or Instructions associated with this specified Power Meter. Once all the Power Meter data is complete you can exit the Power Meter Dialog. In the Power Meter tab, enter the applicable Energy Pricing for the Various Power Meters. Once all of the data for the Energy Management tabs has been entered you are ready to calculate the Energy Management. Click on the Calculate button on the Taskbar. Once the Calculation process is complete you will get numerous detailed results. The Results Summary section will give you detailed results about the Energy Management study. In the Results Summary you can compare results based on the entire billing period. An example is shown below: Carbon Emission Analysis Carbon Emissions can also be considered when running a Energy Cost analysis. You can choose the pumps to be included in the analysis at the same time as you select which pumps to include with the energy cost analysis. In order for the carbon emission analysis, you need to enter a Carbon Dioxide Emission Factor to complete the analysis. To do this, click in a cell under the column header Unit Carbon Emission. This will open the Unit Carbon Emission dialog. Create a new definition by select the New icon, then enter your value for the carbon dioxide emission factor. Click “Close” to return to the Energy Cost dialog and choose the new unit carbon emission definition from the pulldown menu. When you select the Compute icon in the upper right, it will now calculate the carbon emissions from the pump. To view the results, select “Pump Usage” directly under the scenario name in the window on the left. In the table, scroll all the way to the left. The Carbon Emission results field will be the last column. See Also Product TechNotes and FAQs Haestad Methods Product Tech Notes And FAQs External Links Hydraulics and Hydrology Forum Bentley SELECTservices Bentley LEARN Server Comments or Corrections? Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

What we are trying to simulate is the storage volume in our network at ADWF flows after a pump failure into our WWTP. So how long before we overflow at the lowest manhole elevation, and from that point, how much storage volume do we have on top of normal flows at ADWF. We are using the Sewergems implicit engine, is this the best option? Thanks

I have missed the webinar of SIG on Fire Flow yesterday, can anyone share the link of the said webinar recorded video?????? Anyone who has attended this webinar must have receive the link of the video from Bentley. Bentley Hydraulics & Hydrology Special Interest Group Workshop: Fire Flow 21 December 2016 07:00 PM EST - 08:00 PM EST

Here is the link to the recording of the workshop, posted on YouTube. (Please visit the site to view this video)

Hello Stephen, Here is the article which explains the differences between the solvers. The Implicit or Explicit solvers are best for analyzing problematic systems or flooding since they use dynamic numerical solvers that can calculate overflow rate and several other things. You also could use hydraulic reviewer tool to see the overflow in the wet well, which is available with Implicit and explicit solvers. Analysis>Hydraulic Reviewer. .

Product(s): Bentley SewerGEMS, SewerCAD, CivilStorm, StormCAD Version(s): 08.11.XX.XX Area: Modeling Problem What are the differences between the SewerCAD (GVF Convex Solver), SewerGEMS/CivilStorm (Implicit and Explicit Dynamic solvers), and StormCAD (GVF Rational Solver)? When should I use StormCAD instead of CivilStorm? Solution The SewerCAD GVF Convex solver uses convex routing and a gradually varied flow profile for design and analysis of of sewer networks including mixed gravity and pressure flow. SewerGEMS is a superset of SewerCAD, including all its functionality, plus two fully dynamic solvers (Implicit and Explicit SWMM) and ArcGIS integration support. SewerGEMS Sanitary was a separate program included with older versions of SewerGEMS V8i (08.11.01.21, 08.11.02.46, 08.11.02.49 and 08.11.02.75). It is installed automatically when installing these versions of SewerGEMS and includes all the functionality of the Bentley SewerCAD product, plus the ability to work inside of ArcGIS. As of SewerGEMS V8i SELECTseries 3 (08.11.03.77+) SewerGEMS Sanitary is no longer available with this specific brand name because of the conversion of all of our storm and sewer products into a unified file format. The unified file format now allows all the storm sewer products (StormCAD, SewerCAD, SewerGEMS, CivilStorm, and SewerGEMS) to open a model created in another product. In creating the unified schema SewerGEMS has been changed to incorporate all the storm sewer solvers, so if you want to run the SewerCAD solver (GVF-Convex) on your network you have the option to. This is really the same thing as having SewerGEMS Sanitary come with SewerGEMS, except you no longer need to open a separate program, and you also have the option to run the GVF-Rational (StormCAD) solver for your model if you choose. In other words, With the SewerGEMS SS3 release Bentley accomplished a convergence of SewerGEMS Sanitary modeling fully into SewerGEMS. As a result SewerGEMS embodies effectively a superset of the capabilities delivered in StormCAD, CivilStorm, SewerCAD, and SewerGEMS. All consolidate into a common data store. All differentiate by the computational solvers that are selectively packaged into each product in service to a range of commercial use-cases across stormwater, sanitary, and combined systems. With this release SewerGEMS Sanitary was deprecated. It was cleanly folded into the SewerGEMS application. How do I know which solver is best for me to use? SewerCAD (GVF Convex) vs. SewerGEMS (Implicit and Explicit) The SewerCAD application (and the GVF Convex numerical solver in SewerGEMS) is best used in systems that have complicated pumping, pressure sewers, and only need to use extended period simulation convex (EPS) routing as opposed to fully dynamic routing. SewerCAD should also be used if you need to perform a constraint-based automated design or if you need to run a steady state simulation, such as for a peak flow analysis with Extreme Flow methods. SewerCAD can be thought of as a bread-and-butter package that delivers conventional design and capacity analysis. Municipal-scale master planning is certainly part of it, but serves very well in site/civil arena as well. Routing is hydrologic with conventional back-water dominant hydraulics. Gravity analysis is complete with well-accepted state-of-the-practice hydraulic grade analysis with form losses. Diversions or splits are handled in explicit ways. I&I, similarly, is modeled using an array of fundamental and appropriate simplifying models. On the other hand, the SewerGEMS/Civlstorm applications layer into the mix solvers for dynamic wave simulation (implicit and explicit (SWMM), with ArcGIS integration support. So, if you have challenging cross-connections, loops or dynamic surcharging and ponding, this gives you the capabilities of EPA SWMM along with Bentley's own implicit solver. SewerGEMS (Implicit or Explicit Dynamic numerical solvers) is best for analyzing existing problematic systems, where catchment rainfall-runoff calculations are required or dynamic wave solutions are needed (if required by the reviewer or by way of the complicated nature of the particular network) or if you must work inside the ArcGIS platform. SewerGEMS can handle complex things like control structures, diversions (without having to enter a diversion rating curve required in SewerCAD/GVF Convex solver) or ponds. Long term continuous simulations would be done using the Explicit solver in SewerGEMS. The "solver" refers to the type of numerical finite difference solution used to solve the St. Venant equations, which describe unsteady one-dimensional, free surface flow. The software contains two different solvers:: Implicit solver - Uses a four-point implicit finite difference solver to find the numerical solutions for the hydrodynamic Saint-Venant equations. The implicit solver tends to be more stable than an explicit solver. This solver is based on the National Weather Service FLDWAV model. SWMM solver - Uses the solver from the EPA Stormwater Management Model version 5. This is an explicit solver which is more prone to stability problems. The results from this solver should exactly matches the results from SWMM 5. There is an initial elevation attribute for manholes using the SWMM engine so that the calculation can simulate a filling process if the initial elevation is lower than the downstream start elevation. However in the Implicit engine the manhole initial elevation is not considered, so the initial manhole elevation is assumed to be the same as the downstream start elevation. Inflow hydrographs are also handled differently by the two engines. The implicit engine interpolates flows between the final flow in the hydrograph and the end time. The SWMM engine assumes that all flows after the final inflow point are zero. *Note: If a catchment is using the EPA SWMM runoff method and not using the default infiltration method specified in the SWMM calculation options then neither hydrology or network will calculate. If you are not using the EPA SWMM runoff method, then any combination of other runoff methods can be used. SewerCAD (GVF Convex solver) is not intended to handle overflow situations such as a case where you want to analyze a problematic existing system. When an overflow condition arises with the GVF Convex solver, the HGL is reset to the rim for an overflow condition. However, the dynamic solvers in SewerGEMS (Implicit and Explicit SWMM solvers) do handle overflow, as they are intended for situations like this (problematic existing systems and/or complex situations). SewerGEMS Implicit and Explicit solvers automatically calculate the overflow using the weir equation. So, SewerGEMS differentiates in the market as being a singular, "top of the line" tool that will carry the engineer though all stages of design and analysis from conventional capacity and automated design of pipe networks into complex hydraulics of combined-sewer systems. SewerGEMS will handle both storm and sanitary models. Importantly, if you have any old StormCAD, SewerCAD or CivilStorm files they can all be loaded into SewerGEMS and brought cleanly ahead. The GVF Rational Solver Note: Currently the StormCAD numerical solver is included with CivilStorm, so CivilStorm has all of the functionality of StormCAD included, by way of selection of GVF Rational as the active numerical solver. The StormCAD product (and the GVF Rational Solver in SewerGEMS and CivilStorm) uses the rational method to analyze or design a system under peak flow conditions based on peak rainfall intensity, while the other solvers in CivilStorm and SewerGEMS such as the Implicit or Explicit, takes rainfall hyetographs (rain vs. time) and develops hydrographs (flow vs. time) for each pipe and routes the flows dynamically. If you are studying a small area where only peak flow is of interest, or if you need to design a system based on the standard rational method, then StormCAD or the StormCAD solver (GVF Rational) should be adequate. If you are working on a large area where hydrograph routing and storage are significant, where you need to use a dynamic solver, or if you need to otherwise analyze more complex effects such as flooding and controls structures, then the Implicit and Explicit solvers in CivilStorm (or SewerGEMS) is what you need. If you get involved with combined sewers where rain and sanitary sewage is carried in the same pipe, we recommend you use one of the dynamic solvers in SewerGEMS. See Also StormCAD FAQ SewerCAD FAQ SewerGEMS FAQ

Product(s): Bentley SewerGEMS, CivilStorm Version(s): 08.11.XX.XX Area: Modeling Problem How do I model wet well overflow? Background When the pump fails to operate then wet well start saturating the water, which causes overflow and the flooding as well. SewerGEMS/CivilStorm can provide you the volume of overflow encountered within the wet well with the use of Implicit solver. Basically, Implicit or Explicit solvers are best for analyzing problematic systems or flooding since they use dynamic numerical solvers that can calculate overflow rate and several other things. Whereas GVF-Convex solver uses the standard EPANET solver for pressure networks, allowing for solid stability with complex pumping situations like manifolds and pumps that cycle faster than the hydrologic time step. However, it is not intended for use with quantifying overflow, so you wouldn't be able to see the overflow with convex solver. Solution The wet well overflow volume can be graphed and seen in the hydraulic reviewer with Implicit engine. Analysis>Hydraulic Reviewer When we talk about overflow it also could include flow at the surface area above the wet well, as it can influence the overflow rate and potentially pond up and recede. To account for the surface above the wet well top Change the wet well type to depth-area and set up the table so as to include the volume above the actual wetwell top. It would be narrow at the bottom where the wetwell actually is, and wide at the top where “overflow” would pond up above the wetwell. This only works if the surface above the wetwell top slopes uphill. If there are depressions at the surface that are lower than the wetwell top, or if the surface slopes downhill and away from the tank, this approach won’t work. If the land slopes away but if you need to account for tailwater effects, then you could try modeling it as a conduit with a start control structure, attached to the wetwell, with an outfall at the other end. The control structure could consist of a weir to simulate the water spilling over the side, and the conduit would represent the slope of the surface. That way the depth in the conduit could influence the overflow rate. Or simply accept the free-outfall overflow over the wet well top. See Also

Hello Stephen, Please also see the below newly created wiki about Wet well overflow modeling, which includes more information.

Dear All, I developed a model which is assigned mainly to simulate the resulted flow from the groundwater levels fluctuations using SWMM/groundwater package through sewerGEMS. The model consists of a main pipe line in the middle of some consecutive sub-catchments. The problem is when I am trying to display the outfall flow graph; the flow appears initially in a certain distribution over the time, which is totally different if I switched to another model in the same window and then got back to the first one and displayed the same graph again without changing any single parameter. the figures are as below ??????? is it a kind of Bug or anything ???

Product(s): SewerGEMS, CivilStorm Version(s): 08.11.05.58+ Environment: N\A Area: Calculations Problem How do I interpret the results when using the surface storage option in a manhole or catchbasin, to check if surface storage is occurring and working properly? What does it mean when a positive value is seen for the "overflow" result field of a node that uses the surface storage option? Solution When the "Surface Storage Type" is set to "Default Storage Equation", "Ponded Area" or "Surface Depth-Area Curve", this models additional storage above the top of the node. For example it can be used to assess depth of flooding in a parking lot about a grate inlet in sag. When using the surface storage option, when the HGL at the node rises above the rim elevation, flow will start to "spill" into the surface storage and the HGL will be allowed to rise further. You can either graph the "Depth (Flooding)" result or graph Hydraulic Grade In and Rim elevation together with the "Flow (Total In)" and "Flow (Total Out)" result to visualize this. When using the Default Storage Equation or Surface Depth-Area Curve, you may see a positive value shown in the "Flow (Overflow)" result field. This overflow is lost from the system and indicates that the surface storage has been exceeded. For the Surface Depth-Area Curve, this happens when the flooding depth exceeds the maximum depth in the curve. For the Default Storage Equation, this occurs at a flooding depth above 2.0 ft (previously this was limited to 0.4 ft which you may see mentioned in the Help Documentation, but was recently increased). Note : Currently, the Ponded Area surface storage type is supported by the Explicit (SWMM) numerical solver. See Also

Thank you, this is helpful. What discharge coefficients are typically used in Pondpack for an XY cross section. For V-notch weirs, I was using 0.6, but I know for rectangular weirs a value of 2.6 was used.

Applies To Product(s): Bentley WaterCAD, Bentley WaterGEMS Version(s): 07.00.xx.xx, 06.xx.xx.xx, 05.xx.xx.xx Original Author: Scott Kampa and Mark Pachlhofer Bentley Technical Support Group Problem How do I import old WaterCAD or WaterGEMS files (such as version 7 and older .WCD file) into WaterCAD or WaterGEMS V8i or How can I import WaterGEMS 3.0 or WaterCAD 7.0 files to WaterCAD V8 XM or V8i standalone while preserving the old presentation settings? Solution To open the model, you must select "database files" from the "files of type" dropdownl, and browse to the .mdb file associated with the older model. The exact steps to take depend on the version that the models were last saved in. The first option is for files saved in version 6.0, 6.5 or 7.0, where the model consists of both a .WCD and .MDB file. The second option is for files saved in version 5.0 and below, in which there is only a WCD file. There is also an option to save presentation settings (color coding, annotation, etc) that are stored in the .wcd file. They will NOT be imported by default. In most cases, this is fine and you can skip the prompt for presentation settings, since V8 XM includes more robust options for color coding and annotation. If you would like to retain the presentation settings, you must export them from version 7 first, by opening the model in version 7 and going to File > Export > V8 XM Presentation Settings. Note, however, that this menu item will not be present unless the exact build of version 7 is 07.00.061.00 and WaterGEMS/CAD V8 XM must have been installed second, since the installation of V8 XM is what places that menu item in V7. WaterCAD or WaterGEMS files from version 7, 6.5 and 6.0 If you have model files from version 6.0, 6.5 or 7, they will consist of a .WCD and .MDB file. The .WCD file contains presentation settings, such as color coding and labeling. The .MDB file contains most of the model data. If you have the .MDB file, you can import the older model by opening WaterCAD or WaterGEMS V8 or V10 (CONNECT Edition) and going to File > Import > WaterCAD/WaterGEMS database. Browse to the .MDB file for the older model and select it. A file upgrade wizard will open. Follow the steps and dismiss the first prompt about presentation settings. The model will open in a new untitled worksheet. Save the model and the model will now be in the WaterCAD/WaterGEMS V8 format. Using the above approach, any color coding or annotations with the older model will not be retained. These can be recreated through Element Symbology (View > Element Symbology). However it is also possible to retain these by first exporting the presentation settings to a special .XML file. This requires that WaterCAD/WaterGEMS V7 and WaterCAD/WaterGEMS V8i is installed on the same machine and that V8i has been installed second. Further steps to do this can be found below in the section "Exporting Presentation Settings". Exporting Presentation Settings Prerequisites: a) You need to have version 7 and 8 both installed on the same machine. b) Version 7 must be installed prior to version 8 in order to have this functionality active, since the installation of V8 XM is what places that menu item in V7. Presentation settings, such as color coding and annotation are not included when importing an older model database, since these are stored in the .WCD file. You can recreate them in the Element Symbology manager in V8i, but if you have WaterCAD/WaterGEMS version 7 installed on the same machine as WaterCAD/WaterGEMS V8i, there is another way. Note that V8i needs to be installed after V7. Also, note that V8i SELECTseries 1 did not have this option (in this case, it is recommended that you upgrade). Instructions: 1. After saving the .WCD file into the version 7 format, go to File > Export > Bentley WaterCAD V8 XM Presentation Settings .This will create a .XML file in the folder that the model is stored. 2. Open up WaterCAD/WaterGEMS V8 XM or V8i and then go to File > Import > WaterGEMS/WaterCAD database 3. When you import the .MDB file and open the file upgrade wizard, the .XML file should be automatically detected as long as the file is stored in the same folder as the .MDB file. Continue through the wizard to upgrade the model. Once it is imported, go to View > Refresh Drawing. The color coding should now be applied. WaterCAD or WaterGEMS files from version 5.0 or older If you have model files saved in version 5.0 or older, you need to use V7 as a bridge. Previous to version 6.0 all model data was saved into the .WCD file. Starting in version 6.0, most of the modeling properties were stored in the .MDB file, while presentation settings were stored in the .WCD file. If you're a SELECT customer and want access to version 7 of WaterCAD that uses a SELECTServer compatible license version please contact technical support by submitting a service request or by phone. To import these old model files, the first step is to open the WCD file in WaterCAD/WaterGEMS version 7. There is a version of WaterCAD/WaterGEMS version 7 that will work with SELECTserver licensing, however that version of the program is not compatible with Windows Vista or later operating systems. If you are installing on a Windows XP machine (or a virtual machine using XP) it can be installed on the same machine as the current V8i program. It will use the same licensing information as well. Next, open the WCD file in WaterCAD/WaterGEMS version 7. You will see a message stating that the program has detected that it is an older version and that it will upgrade the files to the version 7 format. Once the program opens, save the file. If you now browse to the folder that the model is stored, you will find a .MDB file as well. Now open WaterCAD/WaterGEMS V8i. Go to File > Import > WaterCAD/WaterGEMS database. Select the .MDB file associated with the model and follow the steps in the file upgrade wizard. The model will open in an untitled worksheet. Save the file and it will now be in the V8i format. What if I don't have access to the older version and need to retain presentation settings? If you do not have access to version 7 (or a Windows XP computer/VM) and need to retain presentation settings or convert a V5.0 (or below) model, compress the model files (.WCD or .WCD and .MDB) into a zip file and submit them to technical support for conversion. This can be done via the Hydraulics and Hydrology Forum (a confidential file transfer process is available) or by Service Request. What if my model file was saved in Cybernet? (Pre-WaterCAD) Converting Cybernet model files to the V8i format

Thanks but while that information is helpful, it doesn't solve our issue. Specifically, how do we simulate a pump failure with the SewerGems implicit engine AND the second part is then how do we calculate available storage in the mains downstream of the first overflow point. Obviously we could just look at length, volume, and size of pipes and work out how many hours storage we would have, but that only works for zero flow. What we are really trying to discover is, if the pumps fail at ADWF flows, how much available storage do we have until the first overflow point and what is the HGL of that outfall?

Hello Stephen, I would set the pump on and off elevations such that the pump does not turn on. Compute the model and animate some profiles of the area in question to observe what happens. You should be able to see from this when flooding first occurs and what happens afterward. Maximum HGL figures are typically also found in the properties of most elements. Additionally, you could graph the Overflow result field for your low manholes and/or add and sort on the overflow or "is overflowing ever?" results in a flextable.

I personally like to draw a profile of the first several pipes upstream of the pump station and watch the HGL rise until it hits the first manhole rim and the second ... Depending on how flat the sewers are and what the HGL at the pump wet well is when the pump shuts off, you may be able to store a lot of water (or not) in the wet well and pipes.

Thanks Jesse, that is what we tried to achieve, however, when I set the "on" level to above the HGL (for example, something that could never be reached "99999", we get the validation error "pump on elevation is not in the range of the upstream node bottom and top elevation". Should we make the upstream Wet Well artificially high (above our HGL) to overcome this?

Stephen, You could do that, but you could also consider making the pump and downstream pressure network inactive ("Is active?" = false). This of course assumes that the downstream hydraulics are not significant for this particular flooding analysis.

Thanks Tom, that is exactly what we have been doing. We have identified the overflow point and from this noted several manholes at low elevations that could have their lids "bolted" and provide additional emergency storage.

Thanks that seems to have worked a treat. I wasn't aware the model would run without an outfall. After further inspection, it seems our results don't give us what we were looking for and don't make sense. We have over 4hrs of storage at ADWF in our trunk mains from first principles, but the model shows it is full at less than two hours. This appears due to higher than expected flows because some of the pump stations in the network are not variable speed and are in fact pumping to Peak Wet Weather. What this exercise has identified are deficiencies in our network design and recommendation for a storage ballast main upstream of the WWTP would be dependent on pump station upgrades to variable speed. EDIT: Additionally, the network flows are below ADWF when we are overflowing and the mains are full when they shouldn't be? So the model is showing inconsistent results that just don't add up. Does the sewergems implicit engine "initialize" the network at the start of a run?

And how do I use the Bentley Open Utilities Designer ....? Because I tried to find it at WaterGEM and I did not find it.