Bentley CivilStorm CONNECT Edition Help

SWMM Calculation Executive Summary

By default, the SWMM Calculation Executive Summary dialog opens after a hydraulic model has been calculated using the SWMM solver. Uncheck the "Show this dialog after Compute" box to disable the default behavior.

You can also open the summary at any time after calculating by clicking Home > Calculation > Summary.

The dialog consists of the following tabs:

Summary Tab

The Summary tab displays the following information, divided into categories:
  • Run Metrics
    • Label: The label of the scenario just calculated.
    • Flow Continuity Error: A metric that defines how well the computed inflows, outflows, and storage values balance out. The closer the value is to zero the better.
    • Runoff Continuity Error: A metric that defines how well the incoming precipitation, catchment runon.
    • Average Iterations Per Step: Average number of trials required to achieve convergence for each time step.
    • Not Converging: Proportion of simulation time where convergence is not achieved.
  • Routing Summary
    • Dry Weather Inflow: The total volume of dry weather flow entering the system over the course of simulation.
    • Wet Weather Inflow: The total volume of wet weather flow entering the system over the course of simulation.
    • Groundwater Inflow: The total volume of groundwater flow entering the system over the course of simulation.
    • RDII Inflow: The total volume of RDII flow entering the system over the course of simulation.
    • External Inflow: The total volume of flow that enters system via Inflows interface files.
    • External Outflow: The total volume of flow that exits the system to outflows interface file.
    • Overflow Losses: The total flow volume that exits the system as flooding or overflow.
    • Evaporation Losses: The total volume of flow that exits the system via evaporation.
    • Exfiltration Losses: The total flow volume that exits the system via exfiltration at storage units.
    • Stored Volume (Initial): The total volume of flow stored at the start of simulation.
    • Stored Volume (Final): The total volume flow stored at the end of simulation.
    • Flow Continuity Error: A metric that defines how well the computed inflows, outflows, and storage values balance out. The closer the value is to zero the better.
  • System Statistics
    • Time Step (Minimum) - The minimum time step required to achieve convergence, when variable time steps are allowed.
    • Time Step (Average) - The average time step required to achieve convergence, when variable time steps are allowed.
    • Time Step (Maximum) - The maximum time step required to achieve convergence, when variable time steps are allowed.
    • Steady State - Proportion of simulation time where steady state computations are performed.
    • Average Iterations Per Step - Average number of trial required to achieve convergence for each time step.
    • Not Converging - Proportion of simulation time where convergence is not achieved.
  • Process Models
    • Rainfall\Runoff? - Specifies if Rainfall\Runoff analysis was performed during the simulation.
    • RDII? - Specifies if a RDII analysis was performed during the simulation.
    • Snowmelt? - Specifies if a snowmelt analysis was performed during the simulation.
    • Groundwater? - Specifies if a groundwater analysis was performed during the simulation.
    • Flow Routing? - Specifies if a flow routing analysis was performed during the simulation.
    • Water Quality? - Specifies if a water quality analysis was performed during the simulation.
  • Analysis Options
    • Infiltration Method - The infiltration method used by the EPA SWMM runoff method during the simulation.
    • Flow Routing Method - The routing method used by the SWMM engine during the simulation.
    • Start Date - The date which the simulation began.
    • Start Time - The time on the Start Date which the simulation began.
    • Stop Date - The date which the simulation ended.
    • Stop Time - The time on the Stop Date which the simulation ended.
    • Duration - The length of time over which the simulation ran.
    • Start Dry Time - The number of days with no rainfall prior to the start of the simulation. This value is used to compute an initial buildup of pollutant load on the surface of subcatchments.
    • Output Increment - The time step which results are reported for the simulation.
    • Hydrologic Increment - The time step length used to compute runoff from subcatchments during periods of rainfall, or when ponded water still remains on the surface, or when LID controls are still infiltrating or evaporating runoff.
    • Dry Step - The time step length used for runoff computations (consisting essentially of pollutant buildup) during periods when there is no rainfall, no ponded water, and LID controls are dry. This must be greater or equal to the Wet Weather time step.
    • Route Step - The time step length used for routing flows and water quality constituents through the conveyance system.
    • Has Variable Time Step? - Is true if an internally computed variable time step was used at each routing time period.
    • Allows Ponding? - Excess water was allowed to collect atop nodes and be re-introduced into the system as conditions permit. In order for ponding to actually occur at a particular node.
    • Maximum Trials - The maximum allowable iterations for each time step to achieve convergence.
    • Head Tolerance - When the difference in computed head at each node between successive trials is below this value the flow solution for the current time step is assumed to have converged.
    • Threads <Count> - The number of threads used in the simulation.

Nodes Tab

The Nodes tab displays statistic attributes for the following node types: Manhole, Catch Basin, Cross Section, Headwall, Outfall, Transition, Wet Well, Pressure Junction and Pond.
  • Node Depths: When the Node Depths category is selected, the Nodes tab displays a table displaying the following:
    • ID - The unique element ID.
    • Label - The element's label.
    • Element Type - The type of element.
    • Depth (Maximum) - The maximum computed flow depth that occurs at this element over the course of the simulation.
    • Time to Maximum Depth - The time at which the maximum depth occurs.
    • Depth (Average) - The average depth that happens at the node over the course of the simulation.
    • Hydraulic Grade (Maximum) - The maximum hydraulic grade that occurs at the element over the course of the simulation.
    • Time to Maximum Hydraulic Grade - Time when maximum hydraulic grade occurs.
  • Node Inflows: When the Node Inflows category is selected, the Nodes tab displays a table displaying the following:
    • ID - The unique element ID.
    • Label - The element's label.
    • Element Type - The type of element.
    • Local Inflow (Maximum) - The maximum amount of flow injected into system at the node.
    • Time to Maximum Local Inflow - The time at which the maximum local inflow occurs.
    • Local Inflow (Total Volume) - The total volume of flow injected locally at the node over the course of the simulation.
    • Flow (Total In Maximum) - The maximum inflow that occurs during the simulation. This flow is the sum of all incoming piped flow, and flow injected into the system at the node.
    • Time To Maximum Inflow - Time when the maximum inflow occurs.

Links Tab

The Links tab will display statistic attributes for all the conduits, channels and pressure pipes in the model.
  • Link Flows - When the Link Flows category is selected, the Links tab displays a table displaying the following:
    • ID - The unique element ID.
    • Label - The element's label.
    • Element Type - The type of element.
    • Flow (Maximum) - Maximum flow that occurs in link over the course of simulation.
    • Time (Maximum Flow) - Time (measured from the start of simulation) when the Flow (Maximum) occurs in this link.
    • Velocity (Maximum Calculated) - In conduits, this value is the maximum average velocity that occurs during the simulation. In pressure pipes, this value is the maximum actual velocity that occurs during the simulation. In gutters, this value is the maximum velocity computed during the simulation under the assumption of a uniform depth of bypass flow.
    • Time (Maximum Calculated Velocity) - The time (measured from the start of the simulation) when the Velocity (Maximum) occurs in the link.
    • Flow (Maximum)/Full Flow - The ratio of the max flow that occurs in the link to the full flow of the current link.
    • Depth (Maximum)/Rise - The ratio of maximum calculated flow depth in the link, to constructed rise of the link.
    • Adjusted Length/ Actual Length - The ratio of the adjusted length of the link to its actual length. This will be a value greater than one if length was increased during the simulation to help the solution to converge.
  • Flow Classification - When the Flow Classification category is selected, the Links tab displays a table displaying the following:
    • ID - The unique element ID.
    • Label - The element's label.
    • Element Type - The type of element.
    • Time (Dry) / Time (Simulation) - The fraction of the total simulation time that the current link spends completely dry.
    • Time (Upstream Dry) / Time (Simulation) - The fraction of the total simulation time that the upstream of the current link spends dry.
    • Time (Downstream Dry) / Time (Simulation) - The fraction of the total simulation time that the downstream of the current link spends dry.
    • Time (Subcritical) / Time (Simulation) - The fraction of the overall simulation time that flow regime in the current conduit is subcritical.
    • Time (Supercritical) / Time (Simulation) - The fraction of the total simulation time that flow regime in the current conduit is supercritical.
    • Time (Upstream Critical) / Time (Simulation) - The fraction of the total simulation time the link spends with upstream critical depth.
    • Time (Downstream Critical) / Time (Simulation) - The fraction of the total simulation time the link spends with downstream critical depth.
    • Time (Normal Depth) / Time (Simulation) - The fraction of time where the flow in the link is governed by Normal Depth.
    • Time (Inlet Control) / Time (Simulation) - The fraction of total simulation time that the culvert spends under inlet control.

Catchments Tab

The Catchments tab shows the following statistics for all catchments in the model:
  • ID - The unique element ID.
  • Label - The element's label.
  • Element Type - The type of element.
  • Precipitation (Total) - The total calculated precipitation depth that falls on the catchment over the course of the simulation.
  • Runon (Total) - The total depth that flows onto this catchment from other catchments or outfalls over the course of the simulation.
  • Evaporation (Total) - The total volume of flow that evaporates off of the catchment over the course of the simulation.
  • Infiltration (Total) - The total volume of flow that infiltrates into the catchment over the course of the simulation.
  • Volume (Total Runoff) - Total volume of the runoff hydrograph.
  • Flow (Maximum) - Maximum flow that occurs in element over the course of simulation.
  • Time (Maximum Flow) - Time (measured from the start of simulation) when the Flow (Maximum) occurs in this link.
  • Runoff Coefficient (Calculated) - The ratio of the total runoff depth to the sum of the total precipitation and runon depths.

Storage Tab

The Storage tab shows various statistics for all Wet Wells and Ponds in the model. The following attributes are displayed:
  • ID - The unique element ID.
  • Label - The element's label.
  • Element Type - The type of element.
  • Volume (Average) - The average stored flow volume over the course of the simulation.
  • Percent Full (Average) - The ratio of the average stored flow volume to full volume of the current storage unit.
  • Evaporation Loss - The ratio of the volume of evaporation loss to the total cumulative flow volume stored over the course of the simulation.
  • Exfiltration Loss - The ratio of the volume which exits the storage unit via exfiltration to the total cumulative flow volume stored over the course of the simulation.
  • Storage (Maximum) - The maximum volume of flow that is stored at one time over the course of the simulation.
  • Percent Full (Maximum) - The ratio of the maximum stored flow volume to full volume of the current storage unit.
  • Time to Maximum Storage - Time when the maximum storage level is reached.
  • Flow (Out to Links Maximum) - The maximum flow that exits to bounding links over the course of the simulation.

Pumps Tab

The Pumps tab displays the following statistics for all Pumps (regular and variable speed) in the model:
  • ID - The unique element ID.
  • Label - The element's label.
  • Element Type - The type of element.
  • Utilized - Fraction of total simulation time which the pump is turned on.
  • Number of Start-Ups - The number of time during the simulation in which the pump turns on.
  • Flow (Minimum Pumped) - The minimum flow pumped over the course of the simulation.
  • Flow (Average) - The average of the flow pumped over the course of the simulation.
  • Flow (Maximum) - The maximum flow supplied by the pump over the course of the simulation.
  • Volume (Pumped) - The total volume of flow supplied by the pump over the course of the simulation.
  • Power Usage - The total energy utilized by the pump over the course of the simulation.
  • Time Below Pump Curve - The fraction of the time utilized the pump operates below its pump curve.
  • Time Above Pump Curve - The fraction of the time utilized the pump operates above its pump curve.

Report Tab

The Report tab displays the original SWMM source report, divided by category. There is also a Save button to save the summary as a .txt file.

Parent topic: Calculating Your Model