The Flow Balance Tool dialog box allows you to perform a flow balance and/or a volume balance on each pressure zone.

For each Pressure Zone, it displays the Zone (if one is associated with the pressure zone), net inflow (flow across the boundaries but not including flow originating from tanks and reservoirs in the pressure zone) or net volume, the demand in that zone, the minimum and maximum elevations in the pressure zone, the minimum and maximum hydraulic grade lines in the pressure zone, and the minimum and maximum pressure in the pressure zone.

The Report button allows you to generate a preformatted report containing all of the data displayed in the tables.

The Copy buttons (above the Pressure Zones and Boundary Elements tables) will copy the contents of the table to the clipboard in a format that is compatible with spreadsheet programs like Excel.

The Highlight Pressure Zone In Drawing button will toggle on/off highlighting of the the pressure zone for the currently active row in the Pressure Zone table.

For Volume balance, the sum of the flows over the run is found using the following formula:

Where:

N = number of time steps

Qi = flow in i-th time step (cfs)

ti= time step duration for i-th time step

The value of Qi is the net flow into the pressure zone at the start of the i-th time step.

ti is the difference in time between the start and end of that time step (because of pump cycling, the time step size changes).