I think we need to focus on the difference between "Simulating" and "Modelling".

A model is a representative of a system you interested in - in this case stream flow.

A model is a simplified system of interest. and modelling is building a model.

But simulation is studying the characteristics of your system (hear streamflow) which cannot be done in real life or it's too hard to do it. and how simulation does that: by using a model.

Right. A model is a tool that provides the user with simulation runs/results.

thanks for contributing.

I meant can we use the terms Modeling and Simulation interchangeably?

Typically, yes, because you need a model to simulate a process. So, I would think yes. I know that "simulation" is used in the title of modeling papers.

I think you can use both terms.