Units

The plugin uses the same sets of units as Epanet, including both SI-based units and US customary units. Some units also depend on the equation used. For reference, Table 1 includes unit conversions.

Note

Within the WNTR python module all units are in pure SI. This plugin automatically translates units to and from SI when reading and writing QGIS Layers.

Table 1 EPANET INP File Unit Conventions

Parameter	US customary units	SI-based units
Concentration	mass /L where mass can be defined as mg or ug	mass /L where mass can be defined as mg or ug
Demand	Same as flow	Same as flow
Diameter (Pipes)	in	mm
Diameter (Tanks)	ft	m
Efficiency (Pumps)	percent	percent
Elevation	ft	m
Emitter coefficient	flow / sqrt(psi)	flow / sqrt(m)
Energy	kW-hours	kW-hours
Flow	CFS: ft 3 /s GPM: gal/min MGD: million gal/day IMGD: million imperial gal/day AFD: acre-feet/day	LPS: L/s LPM: L/min MLD: million L/day CMH: m 3 /hr CMD: m 3 /day
Friction factor	unitless	unitless
Hydraulic head	ft	m
Length	ft	m
Minor loss coefficient	unitless	unitless
Power	horsepower	kW
Pressure	psi	m
Reaction coefficient (Bulk)	1/day (1st-order)	1/day (1st-order)
Reaction coefficient (Wall)	mass /ft/day (0-order) ft/day (1st-order)	mass /m/day (0-order) m/day (1st-order)
Roughness coefficient	0.001 ft (Darcy-Weisbach) unitless (otherwise)	mm (Darcy-Weisbach) unitless (otherwise)
Source mass injection rate	mass /min	mass /min
Velocity	ft/s	m/s
Volume	ft 3	m 3
Water age	hours	hours