Source Specific Water Age

[feleke]

Hi Kester, I hope this message finds you well.

I am currently working on an application that requires estimating water age specific to individual inflow sources (e.g., river discharges, tidal inlets) within the EEMS framework. I understand that the built-in AgeTracer module provides the bulk average water age at each location, regardless of origin.

However, for my use case, I would like to extract the average age of water originating from each source independently.

I would like to ask:

1. Does the current EEMS post-processing environment support calculating source-specific water age, assuming I define unit passive tracers and corresponding age-integrated tracers for each source?
2. If not directly supported in the post-processing tools, is there any recommended workflow or utility within EEMS to assist with this kind of analysis?

• For example, is there a feature to compute Age × Concentration / Concentration directly across tracer fields?
• Are there any built-in masking, thresholding, or formula-evaluation tools in the GUI?

Any documentation, examples, or suggestions you can provide would be greatly appreciated. I am currently exploring external post-processing (e.g., in MATLAB or Python), but I would prefer to use built-in EEMS tools if possible.

Thank you for your continued support and for providing such a powerful modeling platform.

[linhntk03]

Hi @feleke

Is this what you’re looking for?
https://eemodelingsystem.atlassian.net/wiki/spaces/EHG/pages/226165216/Age+of+Water+Tutorial

[kescandrett1]

Using the multiple dye option, you can set a 0-order equation for a dye at each inflow. You can then specify the coefficient rate as -1 to calculate the age of water for each dye.

https://eemodelingsystem.atlassian.net/wiki/spaces/EK/pages/240222322/Dye

[feleke]

Suppose you have five inflow sources and you’re interested in analyzing the water age from two of them. You set up two dye tracers, assigned to different classes, and designated them as “age” in the setup. However, both tracers produced identical age distributions in the model output.

How can I ensure that each dye class is correctly linked to the specific inflow I’m targeting? Is there a step I might have missed in setting up the dye classes or boundary assignments? Any guidance would be appreciated

[kescandrett1]

You can set a different dye class to each inflow and then set to age of water. Be sure to set them as time varying. We have checked this with EEMS 10.3 and later and it gives results as expected.