How to trace water through project area (Water Overlay)

To track water in a hydrological system, i.e. find where water from a specific point flows to, it is possible to artificially add a chemical emitter in the water system. Any water passing through that construction will pick up the chemical. By having a result type added which highlights that chemical, the flow of the water can be tracked quite accurately.

For the purposes of this scenario, a simple hydrological model will be assumed, although the same technique can be used for breaches and other calamitous scenarios. We will also assume we can use the SUBSTANCE_A particle as our "tracker". We will track any water flowing through a specific location.

If SUBSTANCE_A is already in use for another purpose, any other substance can be used. At least one substance should be unused in order to fulfill this use-case. The instructions on this page will assume SUBSTANCE_A.

Requirements

Before implementing this use-case, make sure you have a basic water model set up. For the specified scenario, the ground overlay is recommended, though any variant will work.

Also ensure the following in your project, if possible:

The hydrological system has some input which allows or causes water flow. An inlet, a pump, or even an incline would be sufficient.
The hydrological system has a SUBSTANCE_A result type, either as main result or as a child result type.
The simulation is set up to output a reasonable amount of timeframes. For most simulation durations, 25 to 50 timeframes will suffice.

Steps

The use-case can be implemented through the following steps.

How to set up water flow tracking:

Configure a base hydrological system.
Find the location, from where you wish to track the water, in the 3D world.
Add an above-ground construction to that location. A construction with the function "reeds" often works best, as it can be placed both on land and in water.
Add the "SUBSTANCE_A" attribute to the added construction, with a value of "1". See How to add and remove an Attribute
Ensure the overlay is recalculated.
Inspect the "Substance A" result overlay. The greater the concentration of the substance in any given location, the more water from the inlet has flowed there.
Select the "play" option in the overlay's legend. The animation will show the flow of the water from the indicated location.

Notes

To track water from different locations or sources (inlets, or other constructions), add the chemical attribute to the construction of which you wish to track the water.

To track water from different sources collectively, each source can be configured with the same chemical attribute. (In the specified example, multiple sources can be provided with the SUBSTANCE_A attribute.)

To track water from different sources with the ability to differentiate between what water came from which specific source, each source can be given a different substance to produce.