Water Course Models

I don't really know anything about modelling rivers, but I know Sally and Lian are interested so I had a look.
A quick google scholar search found The influence of grid shape and grid size on hydraulic river modelling performance (2019).
So, unsurprisingly, there is an active research area in computational models for rivers. A new term for me from the abstract was bathymetry accuracy. Can anyone explain?
Another paper An integrated modelling framework for regulated river systems describes an Integrated Modelling System.
These models include things like rain fall, water basin shape, water basin composition, and plants.
It seems they are making advancements in managing the water basin to deal with flooding and water quality using In silico models.
I don't really know, but it seems to me that if you're doing research in these areas, you should at least know about these models.