Hi Gumby,
Here is a link to an older post of mine showing how I did my standpipes.
Prior post with diagram of standpipe.
Fastening my pond standpipe was easy, I made a big tripod and used stainless steel anchors into the bedrock. The hard part is (as you said) the concerns about ice and ice flows.
This has been in since 2004 and working great. Normal summer operation is drawing off the bottom with the level set by the standpipe in the dam. For winter I draw down to the pond standpipe. Since I have the springs overflowing year round, I put an insulated & counterweighted 32 gal plastic trash can over the standpipe in the pond. It has a couple of pvc pipes inside across the top so it can't suck down onto the pipe. The flow (5-10 gpm in winter) and the insulated cap keeps it from freezing.
I was planning on an exposed overflow down the backside (because we like the sound), but the more cautious and practical side of me is glad I went with the PVC culvert. No worries about erosion etc. If there is no reason for you to draw off the top, you could certainly skip the pond standpipe. I would still put a flap valve on the inlet side so you work on the outlet should you need to.
Hope that gives you some more ideas to consider.
I have some other thoughts and observations on this design if you are interested, otherwise I'll save the paper.
