Subject: Pump / Force Main System in InfoSWMM and SWMM 5

The basic system consists of:

· Wet Well and its associated physical parameters,

· Pump Type

· Defined Pump Curve,

· Downstream Pressure Node and

· Downstream Force Main

Figure 1: The Basic 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.

Step 2: Define the Pump Type

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

Step 4: Set a Surcharge or Pressure Depth at the Downstream end of the Pump

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.

Step 5: Force Main Data

Define the downstream pipe(s) from the pump as Force Main conduits with either a Hazen Williams or Darcy-Weisbach coefficient (defined in the SWMM 5 options or the Run Manager of InfoSWMM)

Step 6: HGL Plot of the Force Main System

Step 7: Pump Summary in the RPT File