# EPANET: [SOURCES]

[SOURCES]

Purpose:

Defines locations of water quality sources.

Format:

One line for each water quality source containing:

- Node ID label
- Source type (CONCEN, MASS, FLOWPACED, or SETPOINT)
- Baseline source strength
- Time pattern ID (optional)

Remarks:

1. For MASS type sources, strength is measured in mass flow per minute. All other types measure source strength in concentration units.
2. Source strength can be made to vary over time by specifying a time pattern.
3. A CONCEN source:
   - represents the concentration of any external source inflow to the node
   - applies only when the node has a net negative demand (water enters the network at the node)
   - if the node is a junction, reported concentration is the result of mixing the source flow and inflow from the rest of the network
   - if the node is a reservoir, the reported concentration is the source concentration
   - if the node is a tank, the reported concentration is the internal concentration of the tank
   - is best used for nodes that represent source water supplies or treatment works (e.g., reservoirs or nodes assigned a negative demand)
   - do not use at storage tanks with simultaneous inflow/outflow.
4. A MASS, FLOWPACED, or SETPOINT source:
   - represents a booster source, where the substance is injected directly into the network regardless of what the demand at the node is
   - affects water leaving the node to the rest of the network in the following way:
     - a MASS booster adds a fixed mass flow to that resulting from inflow to the node
     - a FLOWPACED booster adds a fixed concentration to the resultant inflow concentration at the node
     - a SETPOINT booster fixes the concentration of any flow leaving the node (as long as the concentration resulting from the inflows is below the setpoint)
   - the reported concentration at a junction or reservoir booster source is the concentration that results after the boosting is applied; the reported concentration for a tank with a booster source is the internal concentration of the tank
   - is best used to model direct injection of a tracer or disinfectant into the network or to model a contaminant intrusion.
5. A [SOURCES] section is not needed for simulating water age or source tracing.

Example:

[SOURCES]
;Node Type Strength Pattern
;--------------------------------
N1 CONCEN 1.2 Pat1 ;Concentration varies with time
N44 MASS 12 ;Constant mass injection