Introduction: InfoSWMM for ArcGIS (Esri, Redlands, CA). InfoSWMM enables engineers to work more efficiently and reliably with very large and complex network models, thanks to improvements in such areas as built-in 64-bit simulation, enhanced water quality modeling, and batch run scenario management using many of the Arc Map tools developed for InfoWater and InfoSewer.. All operations of a typical sewer system — from analysis and design to management functions such as water quality assessment, pollution prediction, sediment transport and deposition, urban flooding, real-time control, and record keeping — are addressed in a single, fully integrated geoengineering environment. The program’s powerful hydraulic and water quality computational engine is based on the current SWMM 5 version, which is endorsed by the USEPA and certified by FEMA.
The Pump Summary Table in Report Manager tells you how often the pumps turn on (Start-Up Count), the percent of the simulation time it was used (Percent Utilized) and the maximum, minimum and average flow for the pumps (Figure 1).
You can also see flows in the downstream links from the pumps in the force mains along with the pumps.
If you use the Mixed Graph Control you see the Pump flows and Link Flows on the same Graph (Figure 2).
You can control the replay of the HGL Plot by altering the stepping time in Graph Settings(Figure 3).
The basic force main system consists of (Figure 4):
- Wet Well and its associated physical parameters,
- Pump Type
- Defined Pump Curve,
- Downstream Pressure Node and
- Downstream Force Main
Here are a few common steps in making a force main system.
Step 1: Wet Well Data
Enter the invert elevation, maximum depth of the Wet Well, the physical shape as either a function or shape table and any evaporation or infiltration (Figure 5).
Step 2: Define the Pump Type (Figure 6)
The pump type is defined by a Pump Curve and the On and Off elevations:
The four types of pumps are:
- Volume – Flow
- Depth – Flow
- Head – Flow
- Depth – Flow
Step 3: Define the Pump Curve in the Operation Tab (Figure 7)
Step 4: Set a Surcharge or Pressure Depth at the Downstream end of the Pump (Figure 8)
Any positive Surcharge Depth in the Node will allow the program during the simulation to keep the node under pressure forcing flow through the Force Main. This is similar to a sealed manhole in InfoWorks ICM.
Step 5: Force Main Data (Figure 9)
Define the downstream pipe(s) from the pump as Force Main conduits with either a Hazen Williams or Darcy-Weisbach coefficient (defined in the the Run Manager of InfoSWMM or H20Map SWMM, Figure 10).
Step 6: HGL Plot of the Force Main System with Advanced Labeling (Figure 11)
Step 7: Pump Operation Curve over time in the Output Report Manager (Figure 12)
There are five ways to model a force main in InfoSWMM or H2OMap SWMM for the combination of full and partial flow in the force main (Figure 15). The InfoSWMM St Venant solution involves three computational points in the Link/Node system (Figures 13, 14 and 15).
- Full Flow using Darcy-Weisbach for the friction loss
- Full Flow using Hazen-Williams for the friction loss
- Full Flow using Manning’s n for the friction loss
- Partial Flow uses Manning’s n for the friction loss for ForceMain Equation options
- All non FM or Gravity Main pipes use Manning’s Equation.
If you use Darcy-Weisbach or Hazen-Williams then an equivalent Manning’s n for a force main that results in the same normal flow value for a force main flowing full under fully turbulent conditions is calculated internally in InfoSWMM (Figure 16).
- Equivalent n for H-W is 1.067 / Hazen-Williams Coefficient * (Full Depth / Bed Slope) ^ 0.04
- Equivalent n for D-W is (Darcy-Weisbach friction factor/185) * (Full Depth) ^ 1/6
A few blogs on Force Mains and Pumps in InfoSWMM and InfoSewer:
The all-important Break Node
Theory behind FM Transitions
Pump Summary Table