Funny this thread popped back up again, I actually found it through google today when doing some research. I remember when you built it and have always liked it. I think I am also going to be adding one very similar for my turtles in the next few weeks.
http://pondplants.biz/index.php?page=TimberPond
Take a look at this link, it has step by step instructions for timber ponds.I love this pond! I am getting ready to attempt my first pond, and this looks like something I could do. Is there some way that I could get you to give me more details? Like, perhaps, what you used (sizes, etc.)? I am a total newbie at this and anything that you could tell me would make my day!
http://pondplants.biz/index.php?page=TimberPond