I haven't been on here for many months. Anyways I see some concerns about my setup the OP referred to.
When I first set up what I referred to as a pit (where the vent meets the water level inside the dam), I had an 18 inch dia. x 36 inch long piece of plastic culvert pipe with an 18 inch grate flush with the dam. When it went into siphon, it was really loud. So I cut the pipe off 12 inches below ground level and capped it while running a 4 inch pipe over 3 feet with an elbow then up to the surface with a vent cap flush with the ground. Now you can't hear it unless you are on the dam. The 4 inch pipe acts as a muffler.
In my picture of my 2 intake pipes, I took the picture before I glued on the caps. I drilled enough holes in the pipes to equal over 2x the flow capacity of the pipes.
With out the vent to the surface, the system would air lock. Which I know someone already mentioned that.
You could make this system with one pipe instead of two. When I designed my system, I figured that I needed around 50 square inches of pipe for my calculated rainfall per acres of watershed. 8 inch pipe = 50.24 square inches and 6 inch = 28.26 square inches. The cost of 6 inch pipe was half of the 8 inch. Two 6 inch pipes gives me 56.52 square inches of pipe. So I decided to go with two 6 inch pipes.
Last edited by DC70; 09/19/18 05:07 AM.
