Welcome to the forum Chris!

You'll find great help here. It sounds like you are on the right track. From what I have read (I'm not even a novice in the pond arts (yet))a pond of your type will be a clay bowl up to the level you desire. That leaves you with the task of successfully building the "bowl". My advice has to stop here as there can be a lot of details to constructing a water tight clay bottom and sides. Those in the know will be by soon to add to your thread I'm sure.

It sounds like you currently have a ground water pond. If you have no appreciable water shed, it will be likely that you will have to pump water to it from the creek (or well) even if your clay bowl keeps it from leaking out. Evaporation and plants can lower water levels over the course of time and supplemental water will be needed. That's probably not too big of a deal for you as it sounds like you have the equipment, the time for the hobby, and the pond is pretty small and it would not take much time to "top it off" on occasion.

Fish on!,
Noel