Pond Boss Forums POND CONSTRUCTION Building a dam Another Siphon Question

Under Siphon Specifics, I was asking if the siphon would work. It did. Now my question is, will it stop?

I drained the lake down, built sediment dams, etc. Lake is now almost full again. I'm not quite ready for it to be full again and would like to drain some water out.

I put the siphon through the dam with a 2" valve on top where I could fill it up and hopefully stop it by opening the valve. I ran 8" pipe to the deepest part of the pond and clear to the edge of a creek on my property. There is now a bigger drop and lot more pipe on the downhill side than previously. I'd like to drain some water out now; but someone raised the possibility that a two inch valve may not be sufficient to stop the siphon on a eight inch pipe with that much pressure. If I start the siphon and opening the valve isn't sufficient to stop the flow, it'll totally empty the lake and I won't be able to stop it. Any thoughts? Will a two inch valve stop an eight inch siphon with lots of drop?

All you have to do to break (stop) a siphon is let air in to the pipe, so that water can flow down both sides. I don't know if a pinhole would be big enough for an 8" siphon, but 2" of airflow should be plenty.

Agree with Theo. 2" should put the breaks on quickly.

I'm not sure if it will stop it. Hopefully a fluid engineer will chime in. That is a 16 to 1 volume ratio. I know you can have an air leak and still get a pretty good syphon. I would be ready with a battery powered sawzall if it were me.
I think it would stop, but I wouldn't bet my lake on it.

A 2" valve stop will stop an 8" siphon with lots of drop. Also if you don't use other options you can cut the pipe in half. You can call me directly at the office mon thru fri from 8 to 12 at 940.665.2258 or email me at [email protected]

I'm planning to give it a go this weekend.

Rangersedge,
Can you get a picture of the siphon at full flow?
I'd love to see it!

Ranger, we usually have the opposite to worry about I gurantee it will stop. If we have the slighest leak it will shut itself off.

You do realize also that you will need a full pipe of water on downslope pipe to get the siphon started? Fairly easy to accomplish with 8"plug and small pump to fill it thru the valve you installed.

Jersey: I'll take pictures.

Greg: The reassurance helps. Thanks! Yes. Won't be a problem. We'll plug the downside and use a gas water pump to fill it up. Planning to do it Sunday. Will check it out in a.m. though. Was wanting to prevent water backing up into one sediment basin. We've gotten so much rain recently, it may have done that already. If so, water level may be mute point.

For years I have used a somewhat simpler method of syphoning. I have several lengths of 2 or perhaps 2 1/2 inch green plastic hose that I buy at farm supply stores. My pond is about three acres and when I draw it down in the fall I am in no particular hurry to drop the lake level.

It might take me three weeks or more to drop it four or five feet.

I attach a brick and a one gallon jug to the lake side end of the hose and, with one person standing on the dam, and another on an opposite bank or in a boat pull the hose out into deeper water. The reason for the person on the bank is to make sure the lakeside hose does not get pulled into the lake. If you don't have help you just stake one end to the bank so it isn't pulled into the water.

With the brick and jug, the hose is underwater but not on the bottom where it might pick up muck and stop the syphon. If you have someone on the bank they make sure the hose enters the water and fills rather than floats. If no one helps you all you need to do is make sure the hose goes underwater as soon as it is the water by forcing it under a heavy object. If you have a concrete block with holes in it and run the hose through it as it goes in the lake you won't have a floating problem.


When the hose is all the way in the lake and full of water, I put an adjustable plug we get where we get the hose and then pull the full hose over the dam until I am sure the dam side hose is lower than the lake side hose.

I then merely open the valve and let the water flow. I monitor the lake level each day and when I have removed as much water as I want I just pull the dam side hose up the back of the dam until the elevation breaks the syphon.

It may take a little longer than you have time for, but it often drops a couple of inches a day when the lake is full and then 5 or 6 inches when the level is down. The most I have dropped the water is about six feet in my pond which has 18 foot depth in spots.

At times I have started two of three shorter syphons and that really draws it down.

All together I have probably spent less than $150.00 for hose, clamps and plugs.

Bing

Nice explanation, Bing.

For a variety of reasons, I never got it done this weekend. I'll let you know and provide pictures as soon as I do. Currently shooting for next weekend.

I thought I'd post a quick update. I haven't tried the drain yet. By the time I had the opporunity, the rains had backed up the water into some of the sediment basins so it was somewhat pointless. The spring / summer in our area has been very dry. It would have been a good year to do more work; but it has been a busy year with lots of stuff going on. The lake has been on the back burner. The biggest personal event was getting married.

I do plan to drain the lake down before the rains hit this fall so I'm taking that old water off the bottom and preventing as much water from going over the overflow. I'd like to find a really good, relatively inexpensive 8" valve for the bottom end; but I'm not sure what type of valve would even be best and haven't taken time to scan ebay or the internet much.

I'll let everyone know how the siphon works (if it starts and does ok and also if it quits when I open the 2" valve - I'm pretty confident it will based upon the responses). I'll try to take some good pictures while I'm at it.

Rangersedge,
I just drained my pond down (I have a bottom drain) about 70". I did it over the course of several weeks using a 2" ball valve to control the flow. I have an 8" pipe through the dam. I may be overly cautious, but I was concerned about going too fast and having the saturated soils slide down with the decreasing water level. I did a fairly fast (.75"/Hr) draw down of about 18" a year ago and had a sandbar area that separates two sections erode when the water got down that far.

Don't know how big your pond is or how steep your banks are, but that 8" pipe is going to move a lot of water and with no means of throttling you may want to limit how far you drop the level.

I'm sure others can respond with experience, where I am supposing...
Good Luck; waiting for pictures.

Update: Only 26 months later! We started the siphon last night on the fourth attempt. 1st = didn't have hose in right way so pumped most of the water back into pond. 2nd = ball too flexible and conformed around straps to allow major leaks. 3rd = straps came loose. 4th = we made sure hose was in right direction, straps were tight, two balls were in pipe and heavy iron plate over end. Worked fine. Just have to ensure have enough water on backside to pull up and over the dam. Solid 8" diameter stream of water shooting out the end.

Weather has changed. Been getting into freezing temps at night last few nights. Worried that pond temp dropping to point that fish moving to bottom; but don't really think so yet so decided to go ahead. We put a great big cage over the end so we could get an idea if it is sucking out fish. Checked this morning. Expected loads of bullheads; but cage only contained two dead channel cats (about 1# and 3#).

We'll see how it goes; but I like having the siphon pipe buried so don't have to worry about it weathering and it is not in the way.

FWIW: We had a few rains recently and the spillway was running over. After about 9 hours of full siphon flow, the spillway is still running over this morning and I couldn't tell that the water level had dropped any.

Thanks for the update. That must be a lot of water coming into the pond. IMO the fish will do ok - they can avoid the siphon if there is enough water away from the inflow. Got any new pics ?

No new pics yet. I need to take some. Intended to this time; but was way past dark when fixing and didn't have extra person to take pics. I guess should / could have stopped to take them myself... I wish now that would have taken pics when were busy burying the pipe; but...

We have confirmation. A 2" valve will stop an 8" siphon with lots of drop. We stopped the siphon this evening. I recorded some video and pics with my Blackberry. I'll upload it within the next few days.

An interesting and logical observation was made. One of my nephews was at the discharge end and another pulled the leash to open the valve (thought it might have a vacuum at the valve - and it did). The nephew at the discharge end said that all of a sudden, the water shot out two feet further than it had been, before stopping. I guessing that when the valve opened and broke the suction, the water was able to run out faster because it didn't have to pull the water up the other side of the pond.

It has been below freezing several of the nights it has been draining and I was worried about losing fish. To my knowledge, we had 6 - 10 channel cats go through the siphon and no other fish. Apparently, being sucked through the pipe, around a couple 45 corners, and shot out into a metal cage is not a fun trip as many were dead when found. The water turbulence and freezing temps may have contributed to that too.

A delay in uploading. I need to figure out a way to convert the videos from Blackberry format to some format that everyone can view.

Update: We've had a few rains and the water level is now much higher. I may have to look at draining it again before spring. At least it prevented a lot of water from going over the spillway and provided an opportunity for bigger fish to eat smaller fish. I've been waiting on an upgrade to version 7 of Photoshop Elements and Premier. It hasn't arrived yet; but I'll work on posting pics and video of the 8" siphon this week whether it comes or not.

My wife, a brother and I set up and started another siphon in a small pond (about an acre) near our house. Just used 20" joints of 2" PVC pipe left over from putting in a water line and a Y shaped piece and valve (plus water pump). Started easy and is running well. Plan to drain that pond down completely, transfer / kill off any remaining fish, possibly rework a little bit, and then stock with fish in the Spring (thinking Rosey Red fathead minnows, possibly some bluegill from selected sources, and possibly some smallmouth bass).

Keep us posted

I have been reading about siphoning....I could do the bucket brick method easily in my little pond...if you have seen my pictures you will see a white overflow pipe...also there is a white plastic bag down in the pond where i think the leak is...when is it appropriate to siphon...when is the best time of year for pond repair ...since it is so low I am thinking maybe herons can enjoy the BG...i realize my pond is a minature...but it is so great to be able to walk out the back door and go fishing...it used to be so fun...anyway I know I am ignorant on this subject so bear with me...

Nancy, ignorance is only a temporary deal.

Only 49 years so far, in my case.

Update: The 2" siphon quit when the plastic valve froze and burst. In hindsight, I should have just put an 89 cent cap over it instead of the $24 valve. Live and learn. I'll start it again soon.

Nancy: We are all ignorant on some things and this is a great site to learn. You can look at all my posts to see how ignorant I still am; but I'm learning! I don't remember how big your pond is; but a siphon can be a good, cheap way to lower your water level if you have enough drop in the topography. As far as being able to conduct the repairs, the summer works far better for me. The trouble is that the dirt (i.e. area in pond previously underwater) may need to dry out fairly well and that may take a while. Downside to lowering your water level in summer or winter is that it may be more likely to result in a fish kill. If that isn't a concern, I'd say drain it so water is at level you want after main portion of rains in late spring so can dry out over summer.