I can't find a tutorial on this anywhere, nor can i figure out how to do it. i just wanna make a small lake, that you can swim in, please someone find me a tutorial or tell me, it would be much appreciated.
Hi, please disregard the stampede of hyped up kiddies, trolling the TES modding community like they do their own CoD forums; they will soon pass like a nasty spell of diarrhea.
To answer your perfectly legitimate question: as the other more serious user said, you need to raise the water level. To do this, you need to right-click-edit the cell you're currently working in, in the cell window. In the pop-up that shows, there's a field for water level, that is set to a standard of about -450000 or something - it doesn't matter. What I found is that, in the CK, a water level of around -500 to -250 will do nicely (don't forget the "-").
One problem that I had, however, was that I could set the number like I told you above, but nothing would happen in the renderer. If that's the case with you as well, just navigate to another cell through the cell window, let it load, and then load up your original cell again (it helps if you name it something you can remember).
I hope this helps.