Jayman,

From the contour map and picture provided, it appears as if you have sufficient slope to incorporate an impoundment pond versus an excavated one, which may end up being the cheaper of the two as far as construction costs. Having said that, with a flowing stream to deal with during construction, you might be looking at some type of coffer dam to divert the stream during construction. I have zero experience in dam construction so take these comments on their face value.

You touched on one issue that I think would be key and that is the soils, especially depth to bedrock. If you had adequate soil depth that would allow you to construct a proper keyway and dam I think you could end up with a nice trout pond, one that, after all my hard work typing out this reply, would be happy to help you fish. Then again, if my memory serves me right, your first pond is one I wouldn't mind having for a lawn ornament!

The permitting process (DEC stream classification) is one item you'll have to do some homework on (or not). Your location says western NY so I'm curious to know what type of critters you have around your area. If you do construct a dam and have beavers/muskrats move in, you'll need to police the activities of these residents. If present, otters would look at a trout pond with happy thoughts. A search on this subject will yield the opinion that they are not welcome at all to most fish raising pond owners.

The best part about this new project is that you'll never have a dry hole by the looks of that stream.

Keep us posted.