Pond Boss Forums POND CONSTRUCTION Building a dam Siphon specifics

All: Great discussion and link on siphoning extremes. I've learned a bunch. Thanks!

After getting back from fishing (3 people, 1 boat, @ 165 minutes, power plant lake, after white bass = 1 released LMB about 16") this morning, I checked it out. The water had dropped enough that the siphon had stopped. As feared it might, the water force had worn through the tarp. In retrospect, I should have known to place a big piece of sheet metal there to absorb the force. I was a little surprised that the tarp also didn't hold up that well in a couple other spots too. I'm not sure what I'm going to do different to improve that situation when I restart it.

Overall, I was very impressed with how well it worked and how easy it was to start. I'm going to order another saddle so that we can have two 8" siphons going when restart it. I'm also awaiting delivery of the remaining 14" pipe. I can only imagine how fast two 8" and one 14" siphons can pull out water.

I'm going to check again into the cost / availability of a check valve for the pond end. From safety / convenience standpoint, it'd be great.

As an alternative, I'm going to check into the cost / availability of a flexible connector / elbow to connect section from dam top to pond. If that piece could flex enough so water end could be raised easily even when in deep water and possibly be easily installed on the dam then swung out over water, it could make it a lot easier.

Barring those, we'll use the balls and straps again. They worked far better than I anticipated. I just realized that I hadn’t mentioned… We drove a four wheeler unto the pontoon boat and then used its winch to pull the pipe end up close enough I could see / reach the end to pop the ball. We then lowered it when siphoning started. Maybe an improvised redneck work around, but that worked fairly well… Each joint makes it about 5 foot deeper and I’m not confident the pipe will have enough flex to allow us to do that ahead out. We might find out…

Given that the siphon has stopped before having chance to add joints, that I doubt if enough flex exists to bring near enough to surface, that lake fills quickly (see spillway pic below), and that the water is cold now; I'm now debating whether to wait a bit to restart siphon.

Which reminds me… I don't remember what type of paint I should use on the pipe to protect it from sun and elements. Any suggestions?

Sorry in advance for size of spillway picture. I cropped it, reduced resolution, and etc.; but it still shows up huge.

Edited: Pic was too huge so I removed it. I can email if anyone knows how to shrink and doesn't mind.

Ranger:

Email it to me and I'll cut it down to size, then post it.

Ranger,

Thank you for your input...you are right about the check valve and ball valve at the end. I was trying to find a ball small enough for a 3" pipe.

I'll post photos when complete.

Rangersedge's Pond Runneth Over:

Rangersedge :

Have you calculated how much water you want to remove and appx. time to do so. We drop our 16 acre pond ( avg. depth 8-9 ft. max 20 ft. little shallow water) 3-4 ft. in a week with a 8 in. siphon. How big is the lake and avg. depth ? The water level can drop in a hurry at the end of the drawdown because the remaining water is in a smaller basin.

Thanks Theo! P.S. I like your signature.

Ewest: It took 17 hours to drop it the first 6" inches. You are right in that it would drop faster as it lowers. I believe the pond is currently a little over 17 acres, current max depth maybe 23 feet, no guess as to average depth. I think I need to pull about 15 vertical feet of water out to get it to the depth I need to do all the work I want. I'm guessing might leave 3-4 acres with a pretty uniform 8 feet of water to support the existing fish. After seeing the 8", I don't think I really needed the 14"; but got a good deal / already received and paid for most. Complications are that the pond seems to fill up really fast when get much rain (see above photo), that we should receive spring rains prior to work, and that exposed dirt will probably need plenty of time to dry before doing the work. P.S. Subscriber and book owner too.

I'm wondering about the impact drawing down and maintaining level throughout spring / summer will have on fish population. 40# fatheads stocked in 2003, BG/RE/CC stocked in fall 2004, LMB stocked in June 2005. BG/RE/CC/LMB stockings all based upon 9 acres I had thought I had.

Rangersedge :

You are wise to think about that now. My concern would be that what you stocked has grown in size and number thus the carrying capacity of the lake as drawdown will become an issue when hot weather arrives. Do you aerate? The LMB will have a field day when it starts to warm with the concentration of 17 acres of forage fish into 4 acres. You may need to stock some 3-5in. BG and RES in spring 07. Do you have a place you could move some to and bring back later? You might want to cull some this spring. The other question that comes to mind is the effect on this years spawn. Have your BG spawned in the pond in summer 05 ? Were the LMB 2in. when stocked in 05 ? If so they may or may not spawn this summer. If not that would be good. Anyway you will have to watch and see if any year class is lost this summer and adjust to the situation , if needed. Brush up on recognizing stress factors in fish as a precaution.

Rangersedge,

This is very interesting, pictures really help too.

What are your plans during the draw down?

Gator

Ewest:

I have considered aeration, but have not done so. The pond is about ¼ mile from my electricity. Considered windmill, but don’t foresee problems when wind is blowing as it catches enough now to create waves (which I presume oxygenate water some?). I posted a question about Solar Bee systems last year, but remember receiving any responses pro or con. I need to check into aeration more.

I do have a couple places I could probably move some BG/RES to. That may be a good idea. Any other suggestions?

All fish were small (2"?) when stocked. I didn’t see any signs of bluegill spawn (nests, etc.) in 05.

I have a plethora of yellow bullheads. Maybe the bass will chomp on them / their young instead of bluegill?

I haven’t tried fishing yet. How large do you think the BG, RES, LMB, CC should be by now?

Alligator:

Plans? What plans? I wouldn’t be doing this now if I actually planned in advance! ;-)

Update:

Yesterday, we added two joints of pipe and started the siphon on the first try again. This should pull out about 10 more feet of water. That may be where we stop. Since I now don’t anticipate using the 14” pipe for siphon, we added those on the end of the 8” pipe to get the water to the ditch without causing problems. I should have done that to start with. It has been raining most of the day today.

Rangersedge :

Good question. The timing of when 2in. stocker fish have their initial spawn in a pond is different from south to north. Down here it is not unusual for age 1 fish (LMB and BG born in the spring) to spawn the next ( 2nd) summer. That is not the case up north. From what I understand it will be age 2 before they spawn up north. Bill or CB1 or Theo or Dave or a host of other northern PBers. can answer that question better. If you don't see small LMB or BG fry/yoy then they probably have not spawned in your pond yet. Bob I think uses Solar Bees in his NY project. You might catch a few CC ,BG/RES just to see their size and condition. That would be good to know.

R:

We stocked 3"-4" BG/RES in May 2003, had a (small) late spawn (of both, I honestly believe) in late Summer the same year.

If I read back correctly, you put in 2" BG/RES in the Fall of 2004. My guess would be that they didn't grow much by Spring 2005, and would have had a lesser chance of a spawn in 2005 than my bream did their first year.

This is just an amateur's guess. You've got a lot more water than I do, probably making it easier to miss seeing what limited spawning activity you might have had in 2005 or the relatively low numbers of new fingerlings that would have resulted. Like ewest said, your direct observations and catch results (and seining, if you did any) are by far the best source of info.

Rangersedge,
AERATION DURING DRAWDOWN
If you have 7’ to 8’ of water depth during draw down you should not have to aerate during this summer. Wind action on 3 to 4 acres of water should keep the upper warm water layer mixed down to 6 ft probably 7 ft deep and 8 ft deep if you have really good wind exposure. If it were my pond I would not worry about aeration unless it does not receive any wind action. Without any wind the water area should contain adequate oxygen down to 4 ft minimum and likely 5 ft. Even in that situation the volume of unmixed anoxic layer should not be large enough to cause a major fish kill if a summer turn over (destratification) occurs.

FISH DURING DRAWDOWN
Basically I foresee no problem with your fish numbers unless you stocked those small fish in with existing adult fish.
1. Your initial stocking densities were for 9 acres, so you under stocked as far as numbers and the actual total acreage of 17 ac. Thus your existing fish densities are not as far off as if you stocked for 17 acres. Food supplies for the NON-PREDATORS may be a little short this summer thus their growth may not be optimum. However they may make up some of this growth when the pond refills and extra biomass or production occurs in 2007 due to the new inundated pond areas.

My opinion is: Fathead spawning and survivability during draw down is dependent on several things; primarily existing cover and availability of spawning substrates. Lack of fathead spawning and spawning of some BG should even itself out as far as fish biomass in the draw down pond. If the LMB haven’t eliminated the fatheads by now they will probably complete that job during drawdown. Thus further lowering fish densities to a more normal carrying capacity of 3 to 4 acres.

Stocking of BG –RES (1”-2”) in fall 2004 should be at 4”-6” this spring (2006) and CC (fall 04) could be up to 8”, maybe? 10”. I suspect CC are mostly 6”-8” this spring if they were not fed pellets. It is possible a few of the advanced BG spawned in late 2005, but I sort of doubt it. It mostly depends on the variability of the size of BG that were supplied. The first main spawn of BG- RES will likely occur this spring (2006). Noticeable water fluctuation during spring and summer and substrate composition may affect their spawning success and recruitment. Survivability of the 2006 hatchlings should be based primarily on the existing size of the pond during draw down.

Your 6/05 stocking of 2” LMB should be 4”-7” this spring. They will eat and grow just fine this summer. Reduced amounts of shallow water during draw down conditions SHOULD allow LMB to adequately crop the young that are produced this summer. Water clarity this spring summer will have a big impact on the efficiency of the LMB predation factor and their growth for 2006.

PS - I have discovered that larger sized bullheads >7") will eat small fish. I cleaned a 10" yellow bulhead last summer with a 2.5" green sunfish in it. Other bullheads also had small fish in them.

Bill :

Thanks for looking in on this thread. As usual you hit a homer. I know Rangersedge will be greatful for the sound advice.

Thanks Theo, Ewest, and Bill! All responses are helpful and Bill's is especially so. Thanks again!

If the spawning conditions / success is not favorable this year due to the drawdown, will that potentially result in more large bluegill (i.e. conditions bad = no spawn = more growth)?

PS: I found a person who really likes to eat bullheads. I'm hoping we can put a significant dent in their population while the water is concentrated. Hopefully, we can catch out a lot of the big ones and the LMB will take out small ones.

Rangersedge - You ask:
If the spawning conditions / success is not favorable this year due to the drawdown, will that potentially result in more large bluegill (i.e. conditions bad = no spawn = more growth)?

Yes. Limited spawn of bgill/RES this summer should cause more food to be available for remaining BG. Although persistance of high turbidities will have a negative affect on fish food production and the ability of fish to feed properly. Hopefully water clarity during draw down will remain normal.

Well... We've had some major rains this past week and my pond is probably close to being full again. The pond side of the siphon is under many feet of water. We are thinking about filling up the downhill side of the pipe, closing the top fill spot, and then opening the downhill side up.

My fear is that the air remaining between the dam and pond side water will kill the vacuum; but I really don't want to do the scuba route right now so we're going to give this a shot.

What do you think? Will it start the siphon or will just empty the downhill side?

Hello Everyone,
I have been to this site alot, but this is my first post. Ebay is :rolleyes: Porn is But this site is
I'm going to throw an uneducated guess at this question. If the distance from the top of the dam to the water(plus the width of the dam at the top)is less than half the distance of the pipe from the top of the dam to the bottom of the dam /end of pipe on the dam side. Hmmm.
For every foot drop in the water in the pipe on the dam side should'nt the water in the pipe on the water side rise one foot? LOL
In short, Yes, well maybe....did I mention guess??
Anyway it's a great site and I'm glad to be here.

Desert Pond

Welcome to the forum Desert Pond. It seems logical that there should be some formula where it depends upon length height of pipe with water vs. without water and the pond water level... I don't know though. May try it Saturday and find out.

Rangersedge,
It's worth trying, my guess would be it won't take.
If it does work would like to know.
There is another way. Fill up the downstream pipe with water. A small vacuum pump or the vacuum off of a gas motor will work to pull the rest of the air out. Plumb the vacuum line to the fill spout, suck out the air and close the valve.

We decided to wait until spring rains pass before trying.

Kent: Good suggestion. We will try that trick if doesn't work otherwise. Thanks!

And the answer is... It worked!

My brother and I tried the siphon this afternoon. There was probably 7 - 8' on the pond side between water level and top of dam. We weren't optimistic, but it worked first try and took a total of 35 minutes from pulling up to pond to watching it flow.

The pond had drained enough to create a little whirlpool over the end of the siphon so we added a joint of pipe last night. Following ewests advice and warnings. We lined up the additional joint and it went right on.

In fact, it went on so sudden and so hard that it drove home the warning NOT to have anything you don't mind having cut off between the two pipes. I had to take a ratchet strap off the end of the existing pipe (would have prevented other pipe from going on) and we worked around the edge some getting it ready so, previously to putting the pipe out there, had fingers near edge and pressure didn't seem that bad. Made point not to get in front of end of course; but vacuum really didn't seem that strong. Later, when lining up pipe, thought we had it in the general area and all of a sudden, it was just WHUMP and the new pipe section was sucked in full depth. Happened so fast and hard, no one would have had a chance to pull fingers / hand / etc. out of the way. They would have just been gone.

Lesson: 1. Just line up pipe and the vacuum will pull it on. 2. It is extremely important to keep stuff you don't want to lose out of the way.

Good job Rangersedge . Please keep us updated on the drawdown and what happens. Can't speak about small 1-2 inch pipe but on 6-8 inch pipe it is critical to keep all body parts and personal items of interest away from the suction end of a running siphon.

I probably should have pointed out that we used ropes tied to each end to line it up. Nephew and I were near connection and brother was on pontoon boat near deep water end of new section.

syphons are very interesting. as ewest notes they can be very dangerous in situations like pinch points when adding pipe joints (especially a cap)or when large diameter pipes are used it is the pressure differential (psi) * pipe area so for a 10 psi differential and an 8 inch pipe there is 500 pounds of force sucking you in, be very carefull snorkelling around the inlet. and the pressure spikes when stopping are much greater than steady state pressure differentials

i have played with syphons several times and have lots of ideas for them. you sure dont need a bulldozer to excavate a pond

that is some big pond you guys are playing with good luck.

plus i wanted to try posting a picture so here is one of my syphons
syphon fountain