	Product(s):	WaterGEMS, WaterCAD
	Version(s):	08.11.03.17 and higher
	Area:	Modeling

Problem

Is it possible to run a multi-point trace analysis, where more than one source can be selected? (to see how much water came from each source reservoir) Or, is it possible to track concentration of multiple constituents in a single run?

Solution

For most, small or medium size models, the best option to accomplish this is to use the Water Quality Batch Run (WQBR)tool, available in WaterCAD and WaterGEMS version 08.11.03.17 and higher.

Note: for very large models that take a long time to run, see the MSX-based option further below.

With WQBR you can view results such as graphs, for the concentration of each constituent, volume of water from each trace source, etc. You can also view tabular reports of results and export for color coding.

Note: this tool does not calculate batch trace and constituent at the same time - they are two separate runs.

Using Water Quality Batch Run

The above tabular results are for trace analysis which shows trace results at each time step for all elements in the model. In trace analysis you can choose between multiple sources of trace and then check the trace percentage for all elements in statistics table by changing trace source.

CONSTITUENT

To perform batch run of constituents along with trace, you can select multiple constituents from alternatives as shown below and then see the concentration of each for selected elements. For this first you need to setup respective alternatives for the constituents and select those alternatives and respective scenario in water quality batch run window.

To view the graphs you need to select elements from drawing for which you want to see results in graphical format and in statistics format, results for elements are shown.

See additional resource below and in the Help.

Note that if you want to model the interaction between multiple constituents, you will need to use the Multi-Species Extension (MSX)

Note also if you are using version 10.00.00.55 and the results of a water quality batch run for trace do not match the results of a regular trace run, this is a known issue in that version (reference # 793707). To resolve this, either contact technical support for the latest cumulative patch set for 10.00.00.55, or upgrade to a newer version.

Reporting

Aside from the graphing and statistical table above, starting with the CONNECT Edition Update 2 release of WaterGEMS and WaterCAD, you can now export the maximum, minimum, and average results for a trace or constituent analysis to an Excel spreadsheet or to user data extensions for use with color coding:

Export to Excel: In the Statistics table, click the Export button in the upper left and choose Export to Excel. The data for different source types will be exported to individual worksheets in an Excel file. For instance, if you have three different Trace sources in your Water Quality Batch Run, you will see three worksheets in the Excel file, one for each source. Each worksheet will display the nodes in the model, as well as the maximum, minimum, and average results for the study.

Export for Color Coding: In the Statistics Table export button, the "export for color coding" will create user data extensions (fields in the element properties) with statistical results for the values for the selected source. For example minimum, maximum and/or average. With this, you can perform color coding on the min/max/average field.

Age, Trace and/or Constituent in a single scenario

If you want to take a single scenario and compute age, trace and constituent at the same time and see all three results in the same scenario, select "Age, Constituent and Trace" as the Calculation Type in the calculation options. This is a new option introduced with CONNECT Edition Update 3, and in a patch for version 10.02.01.06 (contact Technical Support if you cannot upgrade).

For older versions, a workaround is to duplicate your calculation options, change the analysis type (age/trace/constituent), then create three separate scenarios and only change the calculation option, then use the batch run feature in the Scenario manager to compute all three scenarios in batch. If you wanted for example to see the age, trace and constituent in the same graph of an element, you could choose all three of the scenarios, then choose the calculate age, trace and constituent and they will show in the same graph.

Batch Trace using MSX

In some situations, using MSX (Multi Species Extension) may be a better option. This is particularly advantageous for very large models that take a long time to run, as the Water Quality Batch Run feature needs to compute the entire EPS and Water Quality for all scenarios. With MSX, you only need to compute the model once, and it can be configured to track separate "constituents" configured with no growth or decay, to act as a way of tracing different sources. Note: this approach is currently not appropriate for models that utilize SCADA overrides as this is not currently supported in MSX runs.

Here is an example of what the MSX Setup would look like for a multi-source trace run:

;
; ** See the MSX Manual for input file format **
;

[TITLE]
Chlorine Decay
[OPTIONS]
; AREA_UNITS [FT2/M2/CM2]
AREA_UNITS FT2 ; Applies to wall species.

; RATE_UNITS [SEC/MIN/HR/DAY]
RATE_UNITS DAY

; SOLVER [EUL/RK5/ROS2]
; EUL = Standard Euler Integrator
; RK5 = Runge-Kutta 5th Order Integrator
; ROS2 = 2nd Order Rosenbrok Integrator
SOLVER EUL

; COUPLING [NONE/FULL]
; NONE = Solution to algebraic equations is only updated at the end of each integration timestep
; FULL = Updating is done whenever a new set of values for rate-dependent variables in the RATE expressions is computed.
; Note: FULL only has any effect when RK5 or ROS2 are being used.
COUPLING NONE

; COMPILER [NONE/VC/GC]
; NONE = Equations are not compiled
; VC = Visual C++ compiler is used to compile equations (NOT CURRENTLY SUPPORTED IN WATERGEMS)
; GC = GNU C++ compiler is used to compile equations (NOT CURRENTLY SUPPORTED IN WATERGEMS)
COMPILER NONE

TIMESTEP 90 ; Seconds
ATOL 0.001 ; Absolute tolerance for comparing species concentrations.
RTOL 0.0001 ; Relative accuracy level on species concentrations. Only applies to RK5 and ROS2 methods.

; WaterGEMS ONLY Advanced Options
; See https://bentleysystems.service-now.com/community?id=kb_article_view&sys_kb_id=daba334847dd7250557fd8de536d433c
; LTOL [Length tolerance]
; FTOL [Flow tolerance]
; ERRCHECK [ON/OFF]

[SPECIES]
;Acknowledged SPECIES UNITS MG/UG/ MOLES/MMOLES/ N/KN/MN
;BULK <specieID> <units> (<atol> <rtol>)
;WALL <specieID> <units> (<atol> <rtol>)
BULK WTPReservoir mg
BULK WellReservoir mg
BULK WaterburyConnect mg

[COEFFICIENTS]
;PARAMETER <paramID> <value>
;CONSTANT <paramID> <value>

[TERMS]
;<termID> <expression>

[PIPES]
;EQUIL <specieID> <expression>
;RATE <specieID> <expression>
;FORMULA <specieID> <expression>
RATE WTPReservoir 0.0
RATE WellReservoir 0.0
RATE WaterburyConnect 0.0

[TANKS]
;EQUIL <specieID> <expression>
;RATE <specieID> <expression>
;FORMULA <specieID> <expression>
RATE WTPReservoir 0.0
RATE WellReservoir 0.0
RATE WaterburyConnect 0.0

The MSX model configuration is as simple as setting the ratio to 1.0 for each water source:

[QUALITY]
NODE 49416 WTPReservoir 1.0
NODE 30 WellReservoir 1.0
NODE 71490 WaterburyConnect 1.0

Using Water Quality Batch run for multi-point trace and multiple constituents

Problem

Solution

Using Water Quality Batch Run

Age, Trace and/or Constituent in a single scenario

Batch Trace using MSX

See Also