This video gives you a quick look at how the dual/interacting systems work. Water seeps into surrounding ground, irrigating lands and spreading in 3 dimensions. You can view it with a hydrology meter tool, and use that as you work to get the right amount of irrigation to farm land, digging canals to do so.
On top of that is the pollution simulation. From this refinery here you can see a mound of pollution being generated, that’s mining tailings, the waste ore after extracting the minerals. If it’s left exposed to the elements like this, runoff from rain will pollute the surrounding environment.
You can see it seeping into the water supply as well, changing it to a pinkish brown. This can have a huge impact on the surrounding plant and animal life, and players will need to make plans to contain or bury waste efficiently in order to generate enough minerals without destroying the surrounding area.