Measurement Units

GeoSWMM performs model computations either in the US Customary units or in the Metric system units. It automatically takes linear measurement units (either meters or feet) from the spatial reference of the data layers and sets the flow units accordingly. The choices for the flow units are:

1.     CFS (Cubic Feet per Second), GPM (Gallons Per Minute), or MGD (Million Gallons per Day) if the linear unit is set to feet.

2.     CMS (Cubic Meters per Second), LPS (Liters per Second), or MLD (Million Liters per Day) if the linear unit is set to meters.

The model results are sensitive to the specified flow units and therefore they should be carefully assigned. Note that the object properties (except the spatial geometry) are not automatically adjusted if the flow unit system is altered.