As you pointed out I have even missed setting it perfectly in a few places.

The water effect which btw is a unity standard asset is just a layer thick and doesnt provide such a feature - or atleast thats all I can make out. Ah yes the under water scenario is totally non existent currently, and i even thought about adding a fence to prevent that type of interaction. If you walk into the lake the colors of everything are the same above and below the water + edge of water sticking out I agree those flowers do look a bit too tall but I just assumed the were originally supposed to be some sort of tall grass type plants without putting too much thought into it. I think the camera should be a little bit higher But most importantly for me - what I realised after doing this over that last few days is that it is not impossible to make something half decent even with the standard/free assets once you put in a bit of effort and imagination.

I must say it was a bit of a steep climb getting familiar with the terrain system at first.

Unity grass asset free