Multi-species model configuration consists of data for multi-species analysis that is dependent on the model (as opposed to setup data which is independent of the model). The configuration is entered under calculation options. Picking the ellipse next to Model Configuration opens the dialog where model configuration data are specified. The semi-colon is used to designate a comment. Text is not case sensitive (e.g. SOLVER and solver are treated the same), but coefficients are (e.g. Kb and kb are different coefficients).

Descriptions of the individual sections of the data are given below:

[SOURCES]

Purpose: Defines the locations where external sources of particular species enter the pipe network.

Formats:

sourceType nodeID specieID strength (patternID)

Definitions:

sourceType: either MASS, CONCEN, FLOWPACED, or SETPOINT

nodeID: the ID label of the network node where the source is located

specieID: a bulk species identifier

strength: the baseline mass inflow rate (mass/minute) for MASS sources or concentration (mass/L) for all other source types

patternID: the name of an optional time pattern that is used to vary the source strength over time.

Remarks:

Use one line for each species that has non-zero source strength.

Only bulk species can enter the pipe network, not wall species.

The definitions of the different source types conform to those used in the original EPANET program are as follows:

MASS type source adds a specific mass of species per unit of time to the total flow entering the source node from all connecting pipes.

CONCEN type source sets the concentration of the species in any external source inflow (i.e., a negative demand) entering the node. The external inflow must be established as part of the hydraulic specification of the network model.

FLOWPACED type source adds a specific concentration to the concentration that results when all inflows to the source node from its connecting pipes are mixed together.

SETPOINT type source fixes the concentration leaving the source node to a specific level as long as the mixture concentration of flows from all connecting pipes entering the node is less than the set point concentration.

If a time pattern is supplied for the source, it must be one defined in the [PATTERNS] section of the MSX file, not a pattern from the associated EPANET input file.

Examples:

[SOURCES]

;Inject 6.5 mg/minute of chemical X into Node N1

;over the period of time defined by pattern PAT1

MASS N1 X 6.5 PAT1

;Maintain a 1.0 mg/L level of chlorine at node N100

SETPOINT N100 CL2 1.0

[QUALITY]

Purpose: Specifies the initial concentrations of species throughout the pipe network.

Formats:

GLOBAL: specieID concen

NODE: nodeID specieID concen

LINK: linkID specieID concen

Definitions:

specieID: a species identifier

nodeID: a network node ID label

linkID: a network link ID label

concen: a species concentration

Remarks:

Use as many lines as necessary to define a network's initial condition.

Use the GLOBAL format to set the same initial concentration at all nodes (for bulk species) or within all pipes (for wall species).

Use the NODE format to set an initial concentration of a bulk species at a particular node.

Use the LINK format to set an initial concentration of a wall species within a particular pipe.

The initial concentration of a bulk species within a pipe is assumed equal to the initial concentration at the downstream node of the pipe.

All initial concentrations are assumed to be zero unless otherwise specified in this section.

Models with equilibrium equations will require that reasonable initial conditions be set so that the equations are solvable. For example, if they contain a ratio of species concentrations then a divide by zero condition will occur if all initial concentrations are set to zero.

Examples:

[QUALITY]

;Set concentration of bulk species Cb to 1.0 at all nodes

GLOBAL Cb 1.0

;Override above condition for node N100

NODE N100 Cb 0.5

[PARAMETERS]

Purpose: Defines values for specific reaction rate parameters on a pipe by pipe or tank by tank basis.

Formats:

PIPE: pipeID paramID value

TANK: tankID paramID value

Definitions:

pipeID: the ID label of a pipe link in the network

tankID: the ID label of a tank node in the network

paramID: the name of one of the reaction rate parameters listed in the[COEFFICIENTS] section

value: the parameter's value used for the specified pipe or tank.

Remarks:

Use one line for each pipe or tank whose parameter value is different than the global value