Is there a way to "reset" water age at a chlorine booster station?

Product(s): WaterCAD, WaterGEMS
Version(s): V8i, CONNECT Edition
Area: Layout and Data Input


Is there a way to "reset" the water age to zero at a chlorine booster station?


A PAX-RCS system for example can “refresh” the chloramine levels and in effect reset the water age. In the model, there is no simple way to “refresh” or "reset" the water age by including some type change at the tank.

An age analysis only "resets" age tracking at reservoir nodes, so the only way to do it, whilst keeping the model calculating age is a method such as the one explained below.

  1. Manually create a reservoir pattern for each tank (and replace the tank with the reservoir), based on the hydraulic results for the tank.
  2. Run the model multiple times as needed (each time the results are liable to change).
  3. Note:
    1. It can be challenging to capture HGL changes at intermediate time steps (affects the HGL pattern).
    2. This can be further complicated if tanks have control conditions on them.


Considering the above mentioned difficulties in hydraulics, this can be achieved by using a constituent analysis.

The way to adjust the chloramine levels at a node element can be done using the 4 different constituent source types. The definitions for those are described in the following article. Based on how the system works one of the source type options should work in this case.

See Also

Forum discussion - Is there a way to "reset" water age, our surrogate for water quality, at a chlorine booster station?

Using Multi-Species Extension (MSX) for advanced water quality modeling

Getting data and setting up for a Constituent Analysis in WaterGEMS and WaterCAD

Understanding the Water Quality Time Step