Sounds like a plan. You may not have to engineer it as sturdy as you think.
Yeah, I was talking it over with my father inlaw. He seems to think 1/2 plywood would work. I just worry about plywood and the water. 1 inch plank will be plenty. It's really just the base that needs sturdy I guess.
I would go much larger than 3 inch, probably the 6 inch. You could always put in a homemade designed gate value to divert any excess flow. My 4 inch pipe with 45 gpm is full. Gravity flow water takes up more space than pressure flow. I would always go bigger than needed to play it safe.
I have more of the 6" so I will use that as suggested.
Sure looks like a lot more than 20 or 40 gpm. Are you sure?I would try and capture as much flow as possible. More flow is always better than not enough.
The only way I have to check is a five gallon pail. It fills it in 12 seconds... So 5 x 4 = 20.
I was also thinking of putting in a small pump to move water from the pond back up to the tank for a bit of extra flow if needed. Something like a bilge pump.. 1500 an hour would be a nice addition. The reason I can't do a big pump is it's 800ft from the house..
