I was thinking of a scenario like below. I know Gus's situation is a bit different. In the sketch below, the pond bottom is lower than the discharge area, so by the time you raise the inlet(for flow rates) it would be near the surface. The green line is a capped pipe to force water into the bottom. Do you think this would work in getting the water flow to stay optimal and still pull water from the bottom?
Granted, the inlet of the red pipe line could be just down on the bottom where the blue arrows are and avoid all the fancy pipework upwards. Should still act like a siphon right? But with your comments above about how the drop of water thru the pipe makes the flow rate increase, the lower it is than the outlet it must decrease significantly? Does it drop to where it's like a standard horizontal drain pipe, or does it even get lower than that?
The larger diameter pipe (12 inch) is the siphon spillway. There is a three inch air vent directly above the pipe. The smaller pipe (6 inch) is a straight pipe that runs through the bottom of the levee. I'm in the process of attaching a cast iron valve to this in order to draw the pond completely down if ever the need arises.
That outlet pipe can drop considerably, a 12" pipe can move some serious water in siphon mode even with a 2' drop from the inlet, I wish you were here, I would just give you a huge piece of road fabric to place under it with a pile of rock for normal flowing. If that thing does go into siphon mode that water is going to be shooting 30'-50' and moving some earth.
On your air vent did he install it so was a couple inches ABOVE the BOTTOM of the horizontal water line pipe ( basically the waterline in normal mode) or are you saying it's above the 12" pipe?
I will add I see a couple things that would worry me, but I'm really nervous about the power of water. If you're throwing rip rap around that inlet then I wouldn't worry much but as it sits now, the inflow through that 12" pipe will eat the dirt/clay away around it and keep eroding it until that pipe is probably sticking out 3'.
The 12" valve is a complete waste of money because you already have the 6" main drain valved, open that and the pond is gone and fast.
The angle of the outlet pipe when in normal mode will not drip out and away from the dam but follow the 12" pipe back into the dam and eat the dirt away until it hits bottom or is being diverted.
If it were me, I would cut that 12" outlet considerably, dig out around it a little and have it as the same height as the 6" pass through, with about 1' of 12" pipe exposed and cleaned well, I would then use purple primer to cover it completely and quickly and while primer is still wet cover it completely in medium dry glue, then take some sand and cover the glued area with sand and start to Press and rub the sand onto the pipe as the glue sets, the next day you will notice you have a 12" emery cloth that you can pour concrete against and get great adhesion and with a couple bags of concrete, trowel in a nice place for the water to flow away from the dam.
What I was planning to do was to cut the 12 inch outflow pipe down to the same level as the 6 inch run through. Then take a 45 degree connector and a 20 foot length of pipe to get any possibity of heavy water flow well away from the levee. I was also gonna run a 20 foot length of 6 inch off the valve. Then lay a couple tons of very heavy rock right around where the pipes will discharge.
If it were me, I would cut that 12" outlet considerably, dig out around it a little and have it as the same height as the 6" pass through, with about 1' of 12" pipe exposed and cleaned well, I would then use purple primer to cover it completely and quickly and while primer is still wet cover it completely in medium dry glue, then take some sand and cover the glued area with sand and start to Press and rub the sand onto the pipe as the glue sets, the next day you will notice you have a 12" emery cloth that you can pour concrete against and get great adhesion and with a couple bags of concrete, trowel in a nice place for the water to flow away from the dam.
What I was planning to do was to cut the 12 inch outflow pipe down to the same level as the 6 inch run through. Then take a 45 degree connector and a 20 foot length of pipe to get any possibity of heavy water flow well away from the levee. I was also gonna run a 20 foot length of 6 inch off the valve. Then lay a couple tons of very heavy rock right around where the pipes will discharge.
Another option I have seen done that would save you some serious cash and it looks really nice is instead of buying expensive 12" and 6" PVC buy one piece of corrugated black sewer pipe with the smooth inner wall (looks like pipe when you look inside) and cut it in half and tuck it under your outlet pipes and fill with dirt level across feathered out to all slopes and plant grass. I would put a 45 on the end of that 12" but it wouldn't be necessary to actually buy a seriously expensive fitting.
Cut your 12" pipe on a 22.5 at the height of your 6" and using a grinder work the cuts until you make a mitered 45 that lays inside the 1/2 piece of black corrugated "gutter" once you have a decent fit, tack the miter together with gorilla tape and pull the "gutter" out.............prime the miter and wrap a roll of PVC tape around the seam to hold it tightly.......then do the sand trick I described place the "gutter" back under the fitting and using a couple bags of concrete make a nice finished fitting and cover it with dirt and seed. If you want the concrete fitting to last for ever take a scrap of chain link or no climb fence and wrap it around the sand prepped 45 first which will act as rebar. Put a extra large Rainbird box over your 6" valve that is cut to form with the corrugated "Gutter" ...... back fill everything with feather dirt, throw some seed down and you have one classy looking finish for next to nothing money wise
A lot of excavation companies have "scrap" or remnants of nice pipe they are willing to sell for pennies on the dollar, we bought 40' of 24" 3034 pipe that was $25 a foot for $5 a foot DELIVERED for our latest pond!
Thanks! The sewer pipe approach sounds promising. I'm not sure I understand how to construct the tie-in. Can you post a picture of how that goes together?
Thanks! The sewer pipe approach sounds promising. I'm not sure I understand how to construct the tie-in. Can you post a picture of how that goes together?
Gus
If you can get a cheap 45 do that but I'm really cheap so I would make my own by first trying to heat bend a 45 using a torpedo heater, if it wasn't do-able I would just miter cut the pipe and do the ole primer, glue sand rub, use some zinc strapping with self tapper screws once I got the fit good using a grinder with a sandpaper pad.
Before I made the concrete outer "shell" I would wrap the 45 with a scrap of chain link and/or No climb fence scrap ( both I have) then drive a couple rebars into the ground and mix up some concrete and make a shell around my fabricated 45
that or just get a piece if 12" Sonotube and make a concrete fitting after placing my corrugated pipe and prepping my 12" PVC pipe with the Primer/glue/sand trick
