Pond Boss Forums INTRO Questions & Observations Siphon or Conventional

The engineering firm that I hired is convinced that a conventional standpipe is better than a siphon system. I'm wanting a siphon. I need some arguments for and against both systems, especially from anyone who has had, or has both.

Thanks all!

Excuse my post, Jersey. I have no opinion on this question, but I wanted to say I am happy that you are moving along and are to a point where you are asking it.

Jersey,

I'm interested in this topic too...why does your engineering firm think the traditional system is better?

How many vacuum systems have they installed and what are the associated issues?

Gator

Jersey, when are we going to get the full, complete, uncensored, unpolitically correct story???

Jersey There is a firm in Macon which advertizes in Pond Boss. Can not think of there name but when I was designing my pond they were very helpful in making that decision. Can not remember all the pros and cons but I went with a standpipe.

Edit: looked it up
www.ponddampiping.com

Jersey

I am in Macon and the folks at PondDam Piping are nice.

I went with two 8 inch syphon pipes. One is a bit lower than the other so first syphon is the one deepest in the pond to drain the deeper water.

The only problem I have experienced is an accidental drawdown. Last fall when all the hurricanes were dumping tons of rain, some trash plugged up the air vent pipe while the system was in syphon mode of operation. I would up with water down 3 feet. Of course with all the rain it filled right back up in a hurry.

I put some screening aroound the air vent pipe and have had no more issues.

Frank

I'm a Civil Engineer, but must admit I'm not an expert on siphons for pond use. But my first thought is why would anyone PREFER a siphon, if a standpipe will do the job?

Siphon is just a more complicated system.

poland_jack,

Im sure you will get a good discussion going on that question!

I would ask what about siphons are more complex? Most times they operate like a simple overflow drain.

Gator

One reason I used syphon was less digging in the existing dam. A small trench to accomodate the two 8 inch pipes was all I needed.

Frank

Why I want a siphon:

1) It pulls the oxygen rich water down from the top and gets rid of the stale water on the bottom.

2) It is not an ugly hole in the water that collects trash

3) It goes over the dam, not through it.

4) It's cool.

Why would anyone want a standpipe?

Oh, by the way, THANKS to y'all for the good comments above. About six weeks ago I posted that in about a week I could tell what I have been doing in order to get the OK to build. Well, I still can't. But suffice it to say I am making progress. The engineers are almost finished with the site plan, which is part of the deal, and that's why I'm asking about a siphon.

Alligator, I don't know why they prefer a conventional system, other than they have never heard of a siphon. They don't know how to size it.

Which reminds me, somewhere I saw a chart or table that compared the flow rate of a standpipe vs. a siphon in gallons/hour. If I recall, the siphon moved 5-6 times as much water for a given diameter. Does anyone know where that chart is?

Jersey,

You hired them. It's your pond, not theirs. Not saying that you shouldn't research, just what ever decision you really want to do, stick with it.

Good point creadmin.
Jersey,
A stand pipe & siphon are equal in all the points you stated above except: Another option is a stand pipe below the dam. My brother has his that way & it's cool too!

Poland_jack

As a CE, I'd like to ask you a question which I honestly do not understand...really not wanting an argument or controversy from anyone...but why would you want a standpipe, when natural spillways cost far less, handle far more water, require less maintenance (virtually none), and never rust away.

The only reason I can see is to be able to drain your pond...in over 40 years of ponding with several different ponds, I have never had the need to lower my water levels. If I did, I would just siphon it out or pump it out, or when renovating, knock a hole in the dam.

Maybe the reason is to get the bad water from the bottom...aerate if that's the concern, it does a far better job, at less cost, and no risk to the integrity of the dam.

I have never had a natural spillway fail to do the job. I have read countless posts on the Forum asking what to do about the leaking, rusting, decaying, poorly installed standpipe.

I can envision situations in pond construction where a standpipe is required as being the only option because of the pond location, but why would you choose that option, if you don't have to?

An NRCS expert told me while I was planning my 4 acre pond that I would absolutely have to have a standpipe in a pond that large....at an additional cost of about $8000. I didn't follow his advice on that or anything else and the pond turned out great. Instead, I listened to a local guru (not an engineer, but builder of many ponds) who said "never put in a stand pipe unless you have to". I went with natural spillways and they have handled huge rains from tropical storms and hurricanes, without any problem whatsoever.

Why do the text books and NRCS always recommend standpipes instead of natural spillways? Thanks in advance for your answer.

Here's a few thoughts.
Earthen spillways are supposed to be designed to accomodate big rain events, not 'normal' rainfall. The theory is that earthen spillways can be eroded quickly, and if broached often, will need to be maintained regularly. That's why earthen spillways are called, 'emergency spillways.'
Larger ponds are designed with overflow pipes, called, 'primary spillways.' There are number of designs. The biggest problem with pipes is installation. If they aren't installed properly, they leak. Installed properly, overflow pipes release normal rainfall in an orderly fashion. Another scenario where pipes are important is if a pond constantly overflows. We would rather it overflow a pipe than dirt. Two big advantages to a pipe is being able to drain the pond and/or release stagnant bottom water. There are many designs of overflow pipes, some of which are of regional importance. For example, you don't want an standpipe on the backside of a dam in the north. It will freeze and likely break the pipe.
A siphon is an outstanding choice for several reasons. First, it can't leak. The pipe sits at water level. The proper size pipe can act similar to an overflow system, releasing 'normal' rainfall. It also allows you to get rid of bottom water. And, you can draw the pond down with a siphon. I'm a big fan of siphons, so long as you pay attention to it and not let it drain the lake during a heavy rain.

Bob,

Maybe I'm just lucky...but tropical storms (30 plus inches of rain over 48 hour period) and normal rainfall have not in any way compromised my spillways. I always place them on "natural" ground...ground that has not been disturbed except for maybe shaving. In two ponds in East Texas that are easily 50 to 75 years old, neither has ever had any spillway work done or required.

Better to be lucky than good I guess, but you will have a hard time convincing me that natural spillways, properly placed and built, are not for "regular" rain events as well as the big ones.

Jersey,

I totally agree. The above is all you need to convince your engineering guys.

A couple of other reasons:

Stand pipes can run deep under a dam, and water under higher pressure can follow the pipe and leak if care is not taken.

Siphon pipes can be smaller diameter than stand pipes to move the same amount of water.

Jersey,

Given the past history of this project, what does the ACOE say? If they gave you the green light to design either system ok, but I'd hate to see you go through a complete site plan design only to have it rejected because the design is not what the ACOE wants.

As a side note, it appears as if you've settled the issue of building a pond and started the planning process. You have been tight-lipped on the project but I think its time to toss our collective PB weight around and file the paperwork to have the files opened using FOIL. With every issue of PB, it seems our consulting grows and grows. By now we must have a good attorney that can handle this for us.

Jersey,

To Robinsons point, siphon systems are less expensive to install, the pipe costs less (because it can be much smaller than a stand pipe) and are less expensive to repair. I saved big bucks on mine.

Best of all - they dont breach the integrity of your dam.

To your earlier post, it is my impression that contractors "go with what they know", and they are resistant to change. If your engineer wont design a siphon, get another one...it's your $. Frankly, I don’t see a need for an engineer to design a siphon system; a quality pond builder can do the job, so can you.

I actually had a contractor tell me "oh, those siphon systems leak". At the time he was standing beside my drained down lake. I have a picture of him leaning against my old stand pipe with an 18" rusted hole in it! :rolleyes:

Gator

We have a siphon spillway system as well as an “emergency” spillway installed in our new pond that filled within two or three months, and the system performed perfectly. It filled again the first year and has not been tested the following three years due to extreme drought conditions.

All new ponds that I have observed in our local N.E. Texas area utilize siphon systems with emergency spillways.

The siphon system appeals to me due to the ability to drain “bad” bottom water even though we have a bottom diffuser aeration system.

The only standpipe that I have seen is a neighboring pond that is so old the boards have rotted off the pier, and is adjoining a decaying mule barn that was a part of a mule breeding/growing operation prior to WW11.

That tells me something about spillway technology, even though the old standpipe worked well three years ago and there is no evidence of and leaks below the dam.

Pray for rain,
George Glazener

Meadowlark, your spillway is an exception, not the rule. Most dams are built up, tying to high points together. Consequently, spillways are engineered site specific. Sure, you want water to run on natural ground, but keep in mind when water runs over a spillway, that 'new' area is receiving much more water than it ever did during its 'natural' life span. If the grade is much steeper than 3% you get a forceful amount of water. Plus, spillways should be engineered to steer water away from the backside slope of the dam. A spillway was not a spillway before it became a spillway. That's why engineers avoid water running over it, except for emergency situations. It's my philosophy to keep water off the spillway as much as possible. When water runs too often, erosion is inevitable, unless the spillway is rip-rapped, concreted, or compacted exceptionally hard. Even a thick mat of ground cover vegetation can't stop erosion. Water seeks its path, then stays with it. That's my experience in many, many cases.
Fish on.

Bob,

Maybe some time you can come see my ponds and spillways. We get as much rain in East Texas on an annual basis as just about anyplace in the Country. I have no erosion problems whatsoever on the spillways...and of course, I take the water away from the backside of the dam.

Maybe the exception comes about in where I always place the spillway(s). I always "build it" at the points (two, on opposite sides of the ponds) where the dam just first touches the natural ground of the bank. That natural, undisturbed ground becomes the spillway. If dirt is needed to direct it away from the backside of the dam, I simply make a very small levy.

Well, it works for me, and it won't be the first time I've been an exception, nor the last, I suspect.

Thanks for your discussion.

ML, I know spillways work for you at your location.

Knowing my own soil conditions and precipitation throughout the year, I would be scared to death to do a pond here without some kind of piped overflow as the primary water exit.

Swales where water naturally drains are the experience I draw upon to make this statement. There are swales here that have not had the soil surface disturbed for decades (maybe longer) which have really good sod cover. They are not in my pastures, so they don't suffer from horses or cattle tearing them up. But during the longest of Ohio's three seasons (Mud, Snow, and Dust), they are wet (and thawed) for 6 to 8 months a year. Heavy runoff can occur pretty much any time during this period, and these swales can easily start eroding at the location of SMALL disturbances (I think deer tracks are more than sufficient) and continue to erode until the runoff stops AND the ground dries (about August). If they aren't repaired, they start eroding again when runoff resumes. Over the expected lifetime of a pond, a pond owner, and the pipe materials available today, erosion on this type of surface in Ohio is (IMO) virtually certain.

Spillways are fine for you. They may be fine for a lot of locations. But I think one would have to have a number of years' experience of local weather and soil to be sure they were OK for a particular pond. I think piped overflows are a better bet ON AVERAGE because this level of experience is lacking for many ponds and locations.

Theo,

Good response. Once again points out the regional nature of this stuff.

Since my pond will be spring fed, I couldn't use a spillway as the primary overflow even if I wanted to. It would run all the time.

Does anyone know where that chart is that compares a siphon to a standpipe in gallons/hour vs. pipe diameter? I think this is what I need to convince my engineer. Yea, I know it's my money, but I'm already $$$ deep into this guy, and I'm happy with his work so far.

Thanks for the great discussion!