Here in Northern AL we average about 45-50 inches rain a year. In fact, it took only about 2 months to fill up.
We're lucky to live in an area with that much rainfall. Ponds of 6ft depth and less are fine (and arguably even preferable)in that climate. Since we don't have drought or freezing problems, and deep ponds have problems of their own, you are probably better the way you are.
Watch out on the creek fish. Make sure you don't transfer undesirable fish such as carp, bullheads, etc. They can be real hard to identify when they're small.
