Are you set on digging a pond? If you want a raised pond....I bought a nice raised pond from Costal Pond Solutions (http://coastalpondsolutions.com/index.php) (a.k.a. Kim's Ponds http://kimsponds.com/). It is about 6 x 6, 425 gallons and 30" deep. It is a complete kit with pond frame, preformed EDPM liner and pump or filter (2 options). They have one that is larger, too.
This is a pic from when I first installed it in early April.
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Oh that looks great, just might be my next project.