Pond Boss Magazine
https://www.pondboss.com/images/userfiles/image/20130301193901_6_150by50orangewhyshouldsubscribejpeg.jpg
Advertisment
Newest Members
Shotgun01, Dan H, Stipker, LunkerHunt23, Jeanjules
18,451 Registered Users
Forum Statistics
Forums36
Topics40,899
Posts557,051
Members18,451
Most Online3,612
Jan 10th, 2023
Top Posters
esshup 28,407
ewest 21,474
Cecil Baird1 20,043
Bill Cody 15,110
Who's Online Now
3 members (Layne, Angler8689, anthropic), 616 guests, and 135 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Joined: Mar 2013
Posts: 46
OP Offline
Joined: Mar 2013
Posts: 46
I rigged up a PVC siphon drain for my 1/3 acre very shallow pond. Basically it is PVC from the pond, up and over the dam, and then downhill. There is a cleanout in the middle of the dam at the high point. I put end caps on both ends, open the cleanout, and fill the entire length of pipe with water from buckets into the cleanout. I replace the cleanout cap, remove the end cap on the pond side, then remove the endcap on the downhill side.

It seems to work famously at first glance. Continues to run as the pond drains down anywhere from 6 inches to a foot. On my first try it continued to drain for about 24 hours. Then, inexplicably, it stops. I thought maybe algae was clogging it up, but then I put the end of the pipe on the pond side into a mesh box trap. I thought maybe air was seeping into the cleanout cap, so I slathered it with thick mud. Same result.

Any ideas?

Last edited by swampmusic; 03/16/15 04:58 PM.

“That boy, I say, that boy's about as sharp as a bowling ball”
Joined: Jan 2014
Posts: 340
Likes: 3
D
Offline
D
Joined: Jan 2014
Posts: 340
Likes: 3
You ever notice a vortex forming at the pond surface? Could pull an air core in if pipe inlet is near water surface.

Joined: Mar 2013
Posts: 46
OP Offline
Joined: Mar 2013
Posts: 46
No I haven't seen that. The pipe is still about 2 feet below the surface and no vortex yet. Certainly something to watch out for though, and something I hadn't considered. Thanks.


“That boy, I say, that boy's about as sharp as a bowling ball”
Joined: Oct 2013
Posts: 6,086
Likes: 93
S
Offline
S
Joined: Oct 2013
Posts: 6,086
Likes: 93
I've not used a siphon, so just repeating what I've read here on PBF or other places.

The outlet has to be below the water level you are siphoning from. If the outlet is not low enough, it could siphon to a certain point to where the outlet was not low enough and stop.

Someone here on PBF had said to put a 45 degree fitting at the outlet to prevent air from following the top of the pipe up and breaking the siphon.


John

I subscribe to Pond Boss Magazine
Joined: Aug 2014
Posts: 154
Likes: 1
Offline
Joined: Aug 2014
Posts: 154
Likes: 1
How much rise vs fall do you have?

Also I would check all the joints for leaks, I had a femco that wasnt tight enough on my siphon stop it one time.

Here is a thread on my pond project where you can see my siphon last summer when I drained it.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Main=30089&Number=390173#Post390173


My pond renovation thread here
Joined: Mar 2013
Posts: 46
OP Offline
Joined: Mar 2013
Posts: 46
I finally figured it out, thanks to your advice, snrub. I put a 90 degree fitting on the bottom end, and it has been gushing like an artesian well ever since. Unfortunately all I could afford was 2" PVC, so it is slow going. When you figure in the rain, well, you get the picture. Now that I have the system figured out (on attempt 11 or 12), I just need about 7 rainless days to finally get it drained.


“That boy, I say, that boy's about as sharp as a bowling ball”
Joined: Aug 2014
Posts: 154
Likes: 1
Offline
Joined: Aug 2014
Posts: 154
Likes: 1
Originally Posted By: swampmusic
I finally figured it out, thanks to your advice, snrub. I put a 90 degree fitting on the bottom end, and it has been gushing like an artesian well ever since. Unfortunately all I could afford was 2" PVC, so it is slow going. When you figure in the rain, well, you get the picture. Now that I have the system figured out (on attempt 11 or 12), I just need about 7 rainless days to finally get it drained.


I drained my 1 1/4ish acre pond last year with a 2" pvc line, the drop rate will speed up as the pond gets smaller as long as you have plenty of drop on the back side. I think it took a little over 2 weeks to get mine lowered down the first time and then there were several restarts after big rains that came thru last fall. I ended up dropping mine over 10 feet using nothing but a siphon.


My pond renovation thread here
Joined: May 2002
Posts: 1,654
Likes: 1
B
Ambassador
Hall of Fame 2014
Lunker
Offline
Ambassador
Hall of Fame 2014
Lunker
B
Joined: May 2002
Posts: 1,654
Likes: 1
I believe that the lower the back side hose is compared to the end that is in the lake, the faster the flow.


"I love living. I have some problems with my life, but living is the best thing they've come up with so far." � Neil Simon,
Joined: May 2011
Posts: 733
F
Offline
F
Joined: May 2011
Posts: 733
Originally Posted By: Bing
I believe that the lower the back side hose is compared to the end that is in the lake, the faster the flow.


Because you don't start gain head pressure till that point right. The hieght of water above the inlet has no effect so long as your not sucking air.


Water is the basis of all life, by design!
Joined: Jun 2007
Posts: 7,099
Likes: 22
R
Ambassador
Field Correspondent
Hall of Fame
Lunker
Offline
Ambassador
Field Correspondent
Hall of Fame
Lunker
R
Joined: Jun 2007
Posts: 7,099
Likes: 22
FWIW, the inlet depth of a siphon only effects the maximum draw down point. Since water seeks the lowest point to flow to, when you remove air from the siphon tube, you essentially set a lower water level point at wherever the outlet is. You need about a 4' drop on the outlet below the pond level to ensure you overcome water tension and friction to maintain a positive discharge PSI and good water flow.

It is actually atmospheric pressure that makes the water flow rather than a vacuum. The siphon system used on ponds is a Pascal's Siphon and atmospheric pressure causes the flow. The maximum lift for a water siphon is just over 34', or atmospheric pressure.

Flow (speed) will drop some as the pond level drops, because net head pressure drops. A pond "appears" to drain faster as it lowers only because there is far less water volume per vertical foot than at full pool due to the sloped sides of the pond, like in a V.

Last edited by Rainman; 03/31/15 01:59 AM.


Joined: Mar 2013
Posts: 46
OP Offline
Joined: Mar 2013
Posts: 46
Ok, Rainman, it looks like this is more complicated than I thought. I have had a couple restarts since my last post. Even with the elbow at the bottom it still won't seem to flow very long. Maybe it's because of atmospheric pressure changes...?

On my first attempt after adding the elbow, it flowed for over 48 hours and looked like it was going to draw all the way down to the inlet. Then overnight it stopped when presumably the pond was almost done draining, judging by how it looked in the evening. But naturally, after it stopped siphoning that night we got torrential rains and the pond was almost full again by morning.

I restarted it and it flowed for almost 24 hours, dropping the pond level about 6 inches. Restarted again yesterday, and as of this morning dropped maybe another 6 inches. Could my fits and starts be the result of atmospheric pressure changes? My outlet is definitely a few feet below the inlet level, but not much more than a few feet.

Thank you all for the great help and info!

Last edited by swampmusic; 03/31/15 08:50 AM.

“That boy, I say, that boy's about as sharp as a bowling ball”
Joined: Jun 2007
Posts: 7,099
Likes: 22
R
Ambassador
Field Correspondent
Hall of Fame
Lunker
Offline
Ambassador
Field Correspondent
Hall of Fame
Lunker
R
Joined: Jun 2007
Posts: 7,099
Likes: 22
Originally Posted By: swampmusic
Ok, Rainman, it looks like this is more complicated than I thought. I have had a couple restarts since my last post. Even with the elbow at the bottom it still won't seem to flow very long. Maybe it's because of atmospheric pressure changes...?

On my first attempt after adding the elbow, it flowed for over 48 hours and looked like it was going to draw all the way down to the inlet. Then overnight it stopped when presumably the pond was almost done draining, judging by how it looked in the evening. But naturally, after it stopped siphoning that night we got torrential rains and the pond was almost full again by morning.

I restarted it and it flowed for almost 24 hours, dropping the pond level about 6 inches. Restarted again yesterday, and as of this morning dropped maybe another 6 inches. Could my fits and starts be the result of atmospheric pressure changes? My outlet is definitely a few feet below the inlet level, but not much more than a few feet.

Thank you all for the great help and info!


The atmospheric stuff was just for the techie's needs.

How far below the water surface is the inlet? Is it creating a whirlpool in the pond that could allow air to be pulled into the siphon tube? Only 3 things can stop a siphon flow once started...Air entering the tube, a blockage, or water levels equalizing.

Is it possible your pond bottom is deeper than the height of your outlet? I would also suggest using electrical tape to help seal every joint.

The high point of your outlet needs to be about 4 feet lower than the level of your pond water and your inlet must always be submerged in water. If a whirlpool is forming over your inlet, air can be drawn down the center of the whirl over a couple feet deep.

Did you put a screen of some type on the inlet? If the inlet is getting plugged by a fish or other debris, tiny air leaks could be drawn in an breaking the siphon also. I use a capped length of pipe drilled with hundreds of smaller holes (1/2" holes in 2" pipe and 3/4" holes in 4" or larger) to reduce inlet velocities, preventing whirlpooling and preventing clogs.

Last edited by Rainman; 03/31/15 10:17 AM.


Joined: Mar 2013
Posts: 46
OP Offline
Joined: Mar 2013
Posts: 46
I have been operating on the assumption that if it siphons for several hours or days and then stops, it must be getting air in it somewhere. Whenever I go to restart it, there is never any evidence of a clog. On attempt 6 or 8 I slid my last section of 2" PVC (at the inlet) into a ten-foot section of 4" corrugated pipe. I am hoping that will deter a vortex.

If my outlet is low enough for the siphon to work, then it should keep right on siphoning until air gets in somewhere, right?


“That boy, I say, that boy's about as sharp as a bowling ball”
Joined: Aug 2014
Posts: 154
Likes: 1
Offline
Joined: Aug 2014
Posts: 154
Likes: 1
I think you definitely have air getting in the system somewhere but it also sounds like you are right on the edge with drop of having enough differential in water levels to make things work as well.

Can you post a picture of your setup, may help us see if something doesn't look right about the setup.

Last edited by BLUE72CAMARO; 03/31/15 11:24 AM.

My pond renovation thread here
Joined: Jun 2007
Posts: 7,099
Likes: 22
R
Ambassador
Field Correspondent
Hall of Fame
Lunker
Offline
Ambassador
Field Correspondent
Hall of Fame
Lunker
R
Joined: Jun 2007
Posts: 7,099
Likes: 22
A blockage on the inlet can be hard to discover sometimes. For example, a fish gets sucked onto the inlet, broadside, and IF air is entering, once the siphon breaks, the water in the pipe will fall down both the inlet and outlet sides, flushing the fish off the inlet. You restart the siphon, water currents pull more onto the inlet, reblocking and reflushing....



Joined: Jun 2007
Posts: 7,099
Likes: 22
R
Ambassador
Field Correspondent
Hall of Fame
Lunker
Offline
Ambassador
Field Correspondent
Hall of Fame
Lunker
R
Joined: Jun 2007
Posts: 7,099
Likes: 22
Originally Posted By: swampmusic

If my outlet is low enough for the siphon to work, then it should keep right on siphoning until air gets in somewhere, right?


Air will stop it, trying to lift the water over 34 feet will stop it, the highest point of the outlet being less than required drop below the pond's water level will stop it.

In my old pond, the pool side of my dam was dug out 10 feet below the grade level of the dry side, so I had to run pipe several hundred feet down a slight slope and into a creek bed to get the required outlet drop.

Last edited by Rainman; 03/31/15 11:41 AM.


Joined: Mar 2013
Posts: 46
OP Offline
Joined: Mar 2013
Posts: 46
Aha! I hadn't thought about a fish blocking it then getting flushed away. I could see a bluegill doing that. I guess I'll just keep re-starting it. I really think I can get it low enough to harvest, because I was a hair away from it last weekend before the rain came, and it should be dry here for a few days. Thanks so much for the help. Maybe next time I restart I'll slide a box trap over the inlet again. I have to admit I am almost dreading success because there is so much muck on the bottom. My wife thinks this whole project has made me even crazier than my usual. I'm like a man possessed draining this pond.


“That boy, I say, that boy's about as sharp as a bowling ball”

Link Copied to Clipboard
Today's Birthdays
Bob Lusk, GaryK, GrizzFan, PhotographerDave
Recent Posts
Happy Birthday Bob Lusk!!
by Rainman - 03/28/24 02:53 AM
Relative weight charts in Excel ? Calculations?
by Mark Dyer - 03/27/24 10:18 PM
Reducing fish biomass
by esshup - 03/27/24 06:17 PM
New 2 acre pond stocking plan
by esshup - 03/27/24 06:05 PM
1 year after stocking question
by esshup - 03/27/24 06:02 PM
Questions and Feedback on SMB
by Donatello - 03/27/24 03:10 PM
Paper-shell crayfish and Japanese snails
by Bill Cody - 03/27/24 10:18 AM
Brooder Shiners and Fry, What to do??
by esshup - 03/27/24 08:47 AM
2024 North Texas Optimal BG food Group Buy
by Dave Davidson1 - 03/27/24 08:15 AM
Dewatering bags seeded to form berms?
by esshup - 03/26/24 10:00 PM
Freeze Danger? - Electric Diaphragm Pump
by esshup - 03/26/24 09:47 PM
Newly Uploaded Images
Eagles Over The Pond Yesterday
Eagles Over The Pond Yesterday
by Tbar, December 10
Deer at Theo's 2023
Deer at Theo's 2023
by Theo Gallus, November 13
Minnow identification
Minnow identification
by Mike Troyer, October 6
Sharing the Food
Sharing the Food
by FishinRod, September 9
Nice BGxRES
Nice BGxRES
by Theo Gallus, July 28
Snake Identification
Snake Identification
by Rangersedge, July 12

� 2014 POND BOSS INC. all rights reserved USA and Worldwide

Powered by UBB.threads™ PHP Forum Software 7.7.5