Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Siphon Questions Building next week!!

Hi Guys,

Well I think I got most of the permiting stuff out of the way but I want to make sure I'm doing this thing right. I've decided to go with 10" pvc pipe for my siphon which should give me 55% greater flow compared to the old 15" stand pipe. My biggest concern is my pipe length. Starting in the pond I'' have about 25ft of pipe going up the dam. 25ft across the dam and maybe 30ft down the back side of the dam to the stream. That means I've got 55ft of pipe before it hits the downward slope. Any issues with this? Does the long section in the middle matter? From what I've been reading it only matters that the pipe going down the back side of the dam is 4ft longer than the piece going down the front side right??

Not 4 foot longer, but 4 foot lower. Lower in elevation than the intake. There has to be more water being pulled down by gravity on the back side than that being pulled up on the pond side. Not sure, but I don't think a long stretch going through the dam will matter as long as it is level or sloping towards the outlet some.

How'd you determine your flow rate for the siphon? Just curious, I couldn't figure out how to calculate it when I did mine. Couldn't find any online calculators for siphon flow. I found formulas, but they were all pretty complex.

Thanks for the reply. I got my technical info from easywayplastics.com They have all the flow information.


Would you guys take a look at my parts order and let me know if I forgot anything for this system? The 8" pipe is so I can drain the pond next year and let it empty for 6 months to dredge. The contractor said he will make two anti seep collars with concrete.

60ft of bell end sch40 pipe 10"
50ft of bell end sch40 pipe 8"

3 10" 22 Elbow
1 10" 45 Elbow
1 10'' x 4'' Vent Tee
1 10" trash guard


1 4" 90* Elbow
1 4" Tee
1 4" Cleanout w/plug
1 4" Coupling

1 8" Clean out with plug

Did you guys use anti seep collars on the siphon piping? I was under the impression that they were not needed because there is little to no head pressure at water level?

I'm a suspenders and belt type of guy. I'd rather spend a little bit more up front and go a bit overkill rather than have to spend a lot later to repair a dam. Not saying that it'll cause problems if you don't use an anti-seep, just that if it were mine, I'd feel a lot better if I did.

I don't see anything you're missing except a trashgaurd for your ventpipe. If that gets clogged with some debris and your system starts siphoning, it may not allow enough air to cut the siphon action when the water level comes back down. Then you'll lose all your water down to the intake level.

I did not do an anti-seep colar for the reason you stated, but we backfilled the trench with good clay and compactted the crap out of it with one of those jumping-jack plate compactors. But that was my choice, there are plenty that would recommend anti-seep collars for insurance.

Post some pictures when you install the pipe, I'd love to check it out!

I also didn't go with anti-seep collars. Since the pipe isn't going straight across the dam with water on the outside of it I didn't see the need. Where would you put them if you actually used them?

I don't see the use of the 8" pipe? I don't see any 8" connectors. I don't see any 4" pipe. What am I missing?

I don't see any adapters going from 10" to 8" either.

why are you using the more expensive sch 40 pipe instead of SDR-35 bell & spigot sewer pipe? You're not dealing with any pressure and the pipe will hold up fine underground.

buzz

Hi guys. The 8" 50ft pipe is for a maint drain. DEP wont let me dredge it now so my plan is to wait until February and lower the pond down and then just open the cap and let the water run thru the 8" pipe for a few months.

The 10" pipe is the sipon system.

I was told sch40 is only good to about 14ft underground. I'm right around that so I didnt want to take any chances with the drain collapsing. The Dep wanted me to incase it in concrete for added strength.

The 10" pipe in sdr-35 was only a dollar or two less expensive. Thats why I went with it all in sdr40

I forgot the 4" pipe. I figure I can pick it up at lowes. All the other pipe and fittings are bell end

Never mind I now see the answer

Well the pipe just showed up and there was a mistake. The 8" came straight and not belled. I could use couplers but the pipe only pushes in about 4" on them compared to 6" on the belled stuff. Back it goes. I also ordered a trash guard, 10ft of 4" pipe and broke down and bought the 10" cleanout. It's almost $300.00 just for the cleanout!!! Thats crazy

For all those wondering it's looking like I'll have about $1500.00 in pipe and $1500.00 in labor to put it in. So $3000.00 to do this. Does that sound about right?

In the interest of saving a few bucks, perhaps you could use a slip-on cap instead of cleanouts. If, and when you need to remove them, cut the pipe off a few inches back from the cap, leaving a sufficient length of pipe attached to the cap so that it can be re-installed with a coupling.

You may get a little wet while cutting off the end of the drain pipe, but you're probably going to get just as wet un-screwing the cleanout plug. And, if the plastic threads are damaged on the cleanout, repairs may involve cutting and gluing, anyhow.

Shoot.. Thats a really good suggestion. I never thought about just cutting off a cap. In reality I'm probably only going to use the drain once in my life time when I have it dredged. It will be buried 3ft under the rest of the time.