Use this to choose the kind of Water Quality analysis you want to run. Also specify the different parameters for the analysis run.

Click on any Tab for more information.


Options

As any of quality options are selected, pertinent fields will be made available for editing.

  • None - No water quality analysis will be performed. No parameters are displayed.

  • Chemical/Temp - Trace the movement of a reactive or non-reactive substance or trace the water temperature. The temperature modeling capability can be effectively used if the temperature of the pipe wall can be considered at a constant value. If the heat transfer mechanism is more complex, then users should use the InfoWater Multi-Species Modeling (MSX) capability. See: Multi-Species Water Quality Modeling Overview.  Also note that the Quality Timestep also controls the temperature calculation timestep. See: Simulation Time  It is recommended that the Quality Timestep should be set at 1/10th of the hydraulic timestep or smaller for best results.

  • Water Age - Calculates the water age over time in an EPS analysis. No additional parameters are required. Water age is the time spent by a parcel of water in the network. New water entering the network from reservoirs or source nodes enters with age of zero.

  • Source Trace - Source tracing tracks over time what percent of water reaching any node in the network had its origin at a particular node. The source node can be any node in the network, including tanks or reservoirs. Internally, the program treats this node as a constant source of a non-reacting constituent that enters the network with a concentration of 100.

  • Multi-Trace - Multiple source tracing tracks over time what percent of water reaching any node in the network had its origin at a particular set of nodes. The source nodes can be any node in the network, including tanks or reservoirs. Internally, the program treats the nodes as a constant source of a non-reacting constituent that enters the network with a concentration of 100. Please Note: the Multi-Trace function described above is a batch process that runs multiple and separate source trace analysis for each individual trace. It is not a simultaneous solution of multiple source traces. It is therefore possible that the combined traces do not fully satisfy continuity especially with tanks that experience both incoming and outgoing flows. The total percentage of water combined from each source may not total 100%.

  • Advanced - The Advance Option is used to select a Multi-Species model (See MSX Model below). The Quality Tab changes to the following display:



Parameters

  • Trace Node - Used for a trace analysis.  For any network node the program will report the percent of water reaching the node that had its origin at the selected source node over time.  The user must specify one node that will act as the origin for the tracing procedure.

  • Multi-Trace on - Select All Sources, Domain or Selection Set from the pull down menu. The Selection Set option requires the Selection Set name or use the Browse  Button to open the Domain Manager or Selection Set Manager as required. The Multi-Source tracing function tracks the percent of water over time  that reaches any node in the network with its origin at a particular set of nodes. The source nodes can be any node in the network, including tanks or reservoirs. Internally, the program treats the source nodes as a constant source of a non-reacting constituent that enters the network with a concentration of 100. Please Note: the Multi-Trace function described above is a batch process that runs multiple and separate source traces for each individual source. It is not a simultaneous solution of multiple source traces. It is therefore possible that the combined traces do not fully satisfy continuity especially with tanks that experience both incoming and outgoing flows over time. The total percentage of water combined from each source may or may not total 100%.

  • Chemical Name - The name of the chemical being analyzed during a water quality analysis.

  • Temperature Modeling - Select this option for water temperature modeling.

  • WQ Tolerance - Solution tolerance for the water quality calculation. The smallest change in quality that will cause a new parcel of water to be created in a pipe. A typical setting might be 0.01 for chemicals measured in mg/L as well as water age and source tracing.

  • Mass/Temp Unit - The unit of mass or temperature for the chemical/temperature being analyzed (usually mg/L).

  • Global Bulk - This reflects the rate at which a chemical will grow or decay due to reactions in the bulk flow of water over time.

  • Global Wall - This reflects the rate at which a chemical will decay due to reactions with the pipe walls over time.

  • Diffusivity (ratio) - For chemical trace the diffusivity is the ratio of the diffusivity of that chemical to the default diffusivity value; for temperature modeling, the diffusivity ratio is the user water thermal diffusivity to the default water thermal diffusivity.


For Water Quality Diffusivity:


      • The default value is 1.3*10e-8 ft2/sec, if no value is given

      • If the given Diffusivity term is > 1.0e-4, it is used as a ‘relative ratio’, i.e. a multiplication factor to the default value,

      • If the given Diffusivity term is < 1.0e-4, it is assumed as the user supplied Diffusivity value


For Thermal Diffusivity:


      • The default value is 1.4*10e-6 ft2/sec, if no value is given

      • If the given Diffusivity term is > 1.0e-3, it is used as a ‘relative ratio’, i.e. a multiplication factor to the default value,

      • If the given Diffusivity term is < 1.0e-3, it is assumed as the user supplied Diffusivity value

  • Limiting Potential - Used to specify a limiting concentration that a chemical can either grow or decay.

  • Global Pipe Bulk Reaction Order - With a water quality analysis, the rate of growth or decay of a chemical may be zero-order, first-order, second-order, etc. (depending on the water quality and the chemical analyzed).

  • Global Pipe Wall Reaction Order - Unlike global bulk, the order of global wall can only be zero-order or first-order (0 or 1).

  • Global Tank Reaction Order - Like the Global Pipe Reaction Order (either 0 or 1), specifies the order of growth or decay for a chemical in a tank only.

  • Roughness Correlation Coefficient - Enter a value that relates to the wall reaction rate constant that is dependent upon the headloss equation being used.  

  • MSX Model - Select the Multi-Species model from the list or use the Browse  button to open the Multi-Species Model editor. See: Multi-Species Model