Lead and Lag Pump Options in SWMM 5

Introduction: If you have a lead and lag pump connecting the same upstream and downstream nodes the normal behavior for the two pumps is to have the the lead pump turn on first followed by the lag pump. The turn on and turn off depths for the pumps determine when the pumps turn of. The pump will work as a simple lead and lag pump based on a wet well elevation without any real time controls.

If you want to add real time controls (RTC) to the lead and lag pumps you can add more sophisticated controls. For example, if you wanted to turn on and off the lead pump at successive time steps then you can add these RTC rules

; New Real Time Control (RTC) Rules

RULE RULE-1

IF PUMP LEAD_PUMP STATUS = ON

AND PUMP LAG_PUMP STATUS = ON

THEN PUMP LEAD_PUMP STATUS = OFF

PRIORITY 1.000000

RULE RULE-2

IF PUMP LEAD_PUMP STATUS = OFF

AND PUMP LAG_PUMP STATUS = ON

THEN PUMP LEAD_PUMP STATUS = ON

PRIORITY 1.000000

RULE RULE-3

IF PUMP LEAD_PUMP STATUS = OFF

AND PUMP LAG_PUMP STATUS = ON

THEN PUMP LEAD_PUMP STATUS = ON

PRIORITY 1.000000

If you want to add a pattern of 2 time steps and 1 time step off for both pumps then you can add this RTC new rule to control the lag pump:

RULE RULE-4

IF PUMP LEAD_PUMP STATUS = OFF

AND PUMP LAG_PUMP STATUS = ON

THEN PUMP LAG_PUMP STATUS = OFF

PRIORITY 1.000000