567234ta:
Couple of points on your list that you may want to consider.
1. The pond may require permits depending on the use and size. Check with your building inspector, town forester, or cooperative extension.
2. Trash dumps should be left alone, or completely removed. Movement and reburial is likely to get you in super hot water with the EPA, with fines that will bankrupt you. Cans & bottles can be recycled. Automotive parts should be recycled - if only as scrape metal - and might net you enough money to cover transport costs. Roofing shingles are usually considered petroleum contaminated and require either burning or recycling - check with a paving company - they might pick them up for nothing. I'd a haul out those cement block pieces, and the slab, and bust them up for road material.
3. Check with your state laws on damming that stream. There are EPA considerations for all wetlands, and safety considerations for all dams on streams. Look for Permit by Notification on the state website. And fines for violations on dam construction can ruin you too.
I'm from New Hampshire which is getting more nanny state by the day. You look like you're in the west, so you might have fewer regs to worry about.