One of the tests that we are currently doing with the Mälaren PyGETM model is to add tracers to the inflows. This serves partially as a proof-of-concept (is the model working correctly?), but also visualises preferential flow paths and an indication of how fast particles spread throughout the lake.
In this short animation, you can see how a tracer (with a fixed concentration of 1.0 mol/m3 in the inflows and an initial concentration of 0.0 mol/m3 in the lake) spreads through Mälaren over a period of 6 months.
