Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Draining a pond with a siphon

I've had an 80+ year old farm pond for about 6-1/2 years now. It's full of muck and small skinny bass. Time and funding has caused the timetable to slip a little on starting the renovation. I have read great information on this site. I'm now finalizing the planning. The first step is to drain the pond. I don't want to break the dam so plan to use a siphon. My first question is, will this work?

A few of the facts:
- 2 acre pond, 5' avg. depth (435,600 CF or 3,260,000 gallons)
- 8' elevation difference from siphon inlet to outlet.
- 4" pvc pipe siphon.
- Pond is spring fed, but only enough to keep up with evaporation.
- Avg. rainfall is 3.3" a Month from Sept. to April. I plan on starting siphon in Sept. 20 acre watershed of 35% woods and 65% pastures.

Is it possible to drain this pond with a siphon, based on this information, in a reasonable time frame?

My hope is to remove muck and make other improvements in 2020/2021, add minnows summer 2021, add fish in 2022, retire in 2024 and sit on the dock with pole in hand for 20+ years.

I'm sure this will be the first of many questions throughout this process. I thank everyone in advance for all the help.

Michael

I believe you can get the majority of the water out with a siphon setup. I drained the majority of two ponds - largest about 1.7 acres - with a 2" PVC siphon setup. The smaller 0.4 acres pond I ran it up and over the dam. The larger pond I ran the 2" PVC siphon down the 8" primary spillway pipe in order to avoid the extra dam height.

Note I said majority of the water. At some point the siphon will quit on you and it will be difficult to get restarted. At that point a pump is needed to get additional water out. Build a "trail" on top of the muck with pallets to walk the pump intake to the water. Slip off the pallet and you will be in trouble assuming the muck is several feet deep.

Nice thing about the siphon is it will run 24/7 until it sucks air in.
Have you already talked with a contractor on getting the muck moved?

I drained a 1 acre pond with 4 inch pvc pipe and flex connectors this past spring. A few lessons I learned:
Put a screen over the inlet pipe in the lake to avoid muck and stuff from being pulled in.
I attached a float (duck decoy) about two feet above inlet so it floated out when first setup.
Attach more pipe on inlet when you installsince you have to start over if you need more.
When filling pipe, I used buckets first time and an electric sump pump the second time.
When using flex connectors, wrap each connector with duct tape, a lot, to ensure vacuum is not broken at a coupler. I learned this after trying to get it restarted about 10 times. Fish hatchery guy said wrap each joint that is on vacuum side.
After pipe was filled, I found unscrewing the cap a difficult job. On my last setup, I just loosened the flex connector with a screw gun. A lot easier.
You won’t get all the water out, very hard to seine fish with mucky shores.
4 inch pvc drained lake much quicker than I thought, about 6 days, 12 feet of water, estimated flow rate of >200 GPM.

Send me a PM if you would like additional suggestions or lessons learned.

Thanks for the responses. Good lessons learned from experience. Thanks for sharing.

Red, I did talk with a contractor about three years ago and put it on hold due to the cost. He is the best pond guy in the area but was hinting he may retire. I need to dig up his number and at a minimum find out who he would recommend.

MO, I'm also surprised at the flow you got from a 4" pipe. Good information to have. I was thinking of a 3-4 week drain time to allow the fish to find the deeper water. I may save some $$ using 2" or 3" PVC.

One thought I had was to use a trash pump and make a large hole in the muck (40'x 20' and as deep as possible) near the dam so the fish have a place to go. I can then remove what I can with a casting net. This would also help get the siphon to the low spot without venturing too far out on the muck.

If I place a valve at the bottom of the siphon, will I be able to control the flow? I'll post a sketch of the siphon for comments at a later date, (before I spend any $$).

Thanks again for the help.

Michael

I don’t know about putting a valve on to control flow. It may be necessary to open the valve wide open to get it running at full capacity before you closed the valve to restrict flow.

I have to say a trash pump would be easier. However, I was not on site to tend to refilling the fuel tank. It might be less costly to rent a trash pump for a week instead of buying pipe and fittings. We are planning to reuse our pipe into home made structure for fish habitats.

I have a couple of postings on here about when I drained my 1 acre (deep) pond and used a siphon for probably 70% of it.

As many have said you eventually lose vacuum and then you'll need a pump, but I managed to lower the water level considerably with just the cost of the PVC/flex couplings/trash cleanout/etc. If you can run the PVC through your existing culvert I'd do so - made for a cleaner solution and for me anyway made mowing a lot easier.

I found that I lost siphon less often with a 45 degree coupling on the downhill end of the pipe. Someone on here suggested that and it worked, I don't know why but it did.

Definitely put a screen/similar on your intake end. I stopped up my siphon and had to restart SEVERAL times due to fish too stupid to swim away/turtles/etc. I'd recommend a piece of PVC with a bunch of holes drilled in it and capped so even if a few holes get blocked you still have intake.

The 45 degree angled up on the discharge is to prevent air from traveling up the pipe, killing the siphon. I did the same thing by using three concrete blocks in a "U" shape around the end to keep it submerged. Also served to slow the water after it exited the pipe to keep it from washing out a hole.

Below is a picture of my homemade guard on the intake. Also had a plate to delay air from being sucked it.

[img]https://i.imgur.com/EyBy04p.jpg?1[/img]

I assembled the pond side of the pipe sections (with flexible Fernco couplings) on land then held my hand on the dam end and shoved it out into the pond. It floated until I took my hand off and let the air out, allowing it to sink in place. Should have gone out in the boat to find where the deepest hole was.