I've got a 1/4 acre pond that's maybe 12' "deep" but the bottom of the culvert pipe where it will overflow is like 18"-20" below the 12', so I've been questioning what I could do to get a bit more out of it while it's only 5' deep. Looking around here and researching I found a few people using what I think is called a weir overflow? I think that's the type that's supposed to be adjustable? I've never done any concrete forming like I'd imagine I'd have to do for this, basically making a concrete box in the end of the culvert with a cutout on the pond side to the height I want to pond to fill to. And I was imaging putting some galvanized walkway grating on top of it.

And the dock, I was thinking floating in the beginning, but the floats are expensive. Right now thinking a fixed 6'x16', and have been questioning how to make the posts, the pond is dug in clay, I just dug a 20" hole maybe a foot from the water and no water is going in so I need to get this done as soon as possible as the last rain raised the water level about a foot. I was thinking I'd auger and put in some 8" sonotubes, get some of those 4x4 concrete post anchors, but am questioning how long the hardware would last in the water. I see others using telephone poles straight into the dirt, or straight into the concrete in sonotubes.