Bob,
Member #1898 tells me you have been following the wisdom (and antics) of this fine collection of pond-mentors much longer than I. For this reason, I presume you have already tapped the pier-construction threads. If not, search the word pier, starting with "Category Intro" so it runs 'em all.
I am right where you are with the same projects before me, albeit a considerably smaller hole in the ground. A little later this morning, I will fire up the digital camera and share some of my trademark "over-kill engineering" plans.