Pond Piping – Don’t Let it just Sit There!
By Bob Lusk
Once the pipe, complete with anti-seep collars, valves, vents and all its best stuff goes in the ground, that’s it…isn’t it?
A small siphon pipe, installed after this pond had some age.
The bulldozer’s shiny silver blade does its magic, shaving and rolling waves of fresh, crisp, bare dirt and depositing it in layers, readying crumbly clay for compaction. Those big, yellow pan scrapers pulled behind huge rubber-tired tractors do what they do…roaring, belching diesel exhaust and moving big volumes of dirt long distances, rearranging the landscape to create the pond of your dreams. You’ve watched, in awe, as fresh soil is moved, rolled, tossed, pulverized and packed into its new home…your dam…behind which, in short order, will be….drum roll, please…your new pond.
As the process has continued, you watched like a nervous father. You ask yourself, “Will this baby leak?” You smell the refreshing aroma of newly tilled soil each time you make your way to the site. “Will it look like I think it will?” …another question you ask yourself as your soul and checkbook take account of what lies before you.
The learning curve is steep.
So is the anticipation.
You and your contractor have had a series of questions and answers during your planning sessions and each has confidence in the other.
As you’ve learned from life lessons, it isn’t what you know that hurts…it’s what you don’t know. Consequently, the learning curve stays steep, even as those giant machines mold your dream into reality.
Yes, you have a good, fundamental understanding of the construction process. You also pretty much get the vision of your piping and the role it plays in your dam. The pipe’s job is to offer the orderly release of some excess water. The emergency spillway handles big rains, the pipe takes care of “normal” rains. Based on its design, your piping system may offer other management strategies, too. For instance, your pipe design may allow for release of bottom water. You may have a valve, so you can drain the pond from time to time. You might have a riser…you might not. You may have a siphon system or a standpipe on the outside. No, wait…you have a standpipe inside the pond. Maybe you have an Agri-Drain style device that allows you to change pool level as you want. Yours is a ball valve, no…it’s a butterfly valve. Wait, it’s a gate valve. Geez…so many choices…and you’ve had to choose.
There are many different systems, different pipes, different materials and different management strategies using your well-thought out pipe design.
Once the pipe, complete with anti-seep collars, valves, vents and all its best stuff goes in the ground, that’s it…isn’t it?
No, it isn’t.
Pipes need love, too.
Designing, installing and then sprinkling holy water on a pipe system doesn’t guarantee a happy life.
Back in August, at a Land and Wildlife trade show in Nashville, Tennessee, I bumped into our long time advertiser and friend, Gerry Jackson, with Southeastern Pipe and Supply in Aiken, South Carolina. Their booth was next to ours.
It was like a family reunion. We shared some photos, talked shop, told some good stories and then it hit me. What a great resource for a Pond Boss story. We’ve not written about the proper care and feeding of pipes in the context a supplier offers.
I asked Gerry, “What do people need to do to take care of their pipes and piping systems?” He smiled. I knew I’d touched a proverbial nerve.
For the next two days, he shared story after story about things he’s seen in his vast experience in the pond pipe industry.
The outflow side of a pipe through a 30+ acre flood prevention lake in north Texas.
“I’ve seen and heard things that no one would ever think could happen with pipes.”
I bet.
I asked, “What should people do about routine maintenance?”
His response was Gatling-gun fast.
“Crack open the valve once a year, maybe twice…make sure it works. Open it a small way…if you don’t, it will freeze up over time.”
“Make sure you have a trash rack over standpipes.”
“Clean the trash off the trash rack regularly. Remove brush, bushes, trees and anything else that catches on it.”
My interest was piqued.
“Gerry, what happens when a limb goes down a standpipe and sticks?”
His common-sense answer stuck. “Shoot it with an arrow with a cord and pull it out.”
What else?
“Inspect the pipe from the backside toe of the dam, looking for any obstruction or things that might clog it…like beavers. Look along the footprint of the pipe, where it was installed. Look for sinkholes and erosion. If there’s a sinkhole, you might be looking at pipe trouble.”
Like what?
“When a pipe separates from a coupling and leaks, it will eat away the dirt from outside the pipe and a sinkhole can form. Also, look just downstream and see if there’s any sign of a sandbar-looking stream of dirt. Dirt eroded around a pipe can be deposited just below a pipe.”
Gerry was rolling now. “Remove trees from your dam before they reach 3 inches in diameter. Trees are heavy. Heaviness collapses pipes…and sometimes dams.”
I hadn’t thought of that. My mathematic side took charge. Let’s see, a 15 foot pine tree, 12 inches in diameter, weighs about 1,500 pounds…but that’s just the saw log. The entire tree, with limbs, weighs at least twice that, maybe more. Ten of those trees add 30,000 pounds of extra weight to a dam. At least. And, those weights are probably really conservative. Prevent trees on your dam. We don’t want the weight…or roots growing toward a pipe.
What are some of the common mistakes?
“Some people put on a trash rack that’s too heavy for the standpipe. Look at a deep-water trash rack, like a Venturi. That device serves two purposes. It removes bottom water and keeps trash out of the pipe.”
What about ponds with older pipe systems?
“If the pipe is galvanized, and is 20-30 years old, it’s rotten. Plan to deal with it.”
He went further, “If it’s 40-50 years old, it’s about to go.”
And, “if there’s a gate valve that hasn’t been opened in many, many years, leave it alone.”
Consult with an expert for pipe design.
I told Gerry a story of a corrugated metal pipe in the bottom of a dam built in 1952. That dam holds a lake which covers more than 125 acres. The entire bottom of that pipe is rotted…as in ‘gone’. A local contractor crawled into the pipe and reported the entire bottom of the pipe was corroded and gone. At the far end of the pipe, inside the lake, is a gate valve that hadn’t been opened in many years. It’s a good thing that valve wasn’t opened. The entire pipe would have collapsed and the dam could have washed out.
What to do in this case?
Gerry was quick…way quick, “Fill the bottom of the pipe with concrete. Form it up, pump concrete all the way to the end of the pipe and add concrete above the area that’s rotted.
This landowner decided to fill the entire pipe with concrete. That pipe wasn’t necessary to accept excess water. It was originally in place to drain the lake. What might have been a liability became moot.
Any of you pondmeisters using HDPE pipe? It’s also called “poly pipe”. Sometimes it’s corrugated, sometimes straight, some comes in rolls. It’s used quite often in the utilities business as conduit.
Gerry told a story of a man who used HDPE pipe in his dam for irrigation purposes and had a grass fire on his dam. The pipe caught fire and burned, starting on the outside, moving inward…inside the dam. Couldn’t be put out. I must’ve had a puzzled look, so he explained. “HDPE is flammable. When the grass fire ignited the pipe, it burned inside the dam, because the pipe acted like its own chimney. Oxygen was available, the pipe was fuel, so everything existed to cause the pipe to burn. It burned under the dirt, to the water, which put it out. But, the next issue was compromise of the dam in that general area”.
Most state regulations won’t allow HDPE in a dam.
Other helpful pipe hints? “If you have a tar-covered galvanized pipe, replace the tar as it evaporates or wears away. Paint the pipe and it will lengthen the life of that pipe, especially on a riser.”
Keith Johnson, with Pond Dam Piping in Macon, Georgia, offered some hints for other types of pond systems, especially PVC. “If you’re installing and maintaining a siphon system, be sure to install it correctly in the first place. If the system calls for a 450 elbow on the outlet end, use it. That’s what keeps air from disrupting water flow when the siphon is rolling. Plus, it helps disperse water to minimize erosion.”
What about maintaining a siphon? “Be sure the vent doesn’t clog. When it’s not in use, we’ve seen and heard different ways the vent gets clogged, especially dirt daubers, wasps and birds.”
Keith ran through his mental list of “Do’s and Don’ts”.
Upon inspecting this pipe, installed in 1952 in this 125 acre lake, the decision was made to fill it with concrete, since there are two other overflow pipes handling the job, one at each end of the dam.
“Corrugated plastic pipe can separate because dirt moves. Joints can split and you’ll have to do some repairs. Most of these pipes have turn-lock in joints.”
Heck, most pipe systems with joints have the potential to separate, especially as dirt moves and adjusts deep inside a dam.
“With galvanized pipes, soils and water cause corrosion. Oxidation from water fluctuation seems to speed up the process. Some can go as quickly as 10-12 years.”
Johnson concurs with opening the valve. “Open your valve at least twice yearly. Not only do you want to keep the valve operating properly, but opening the valve allows any silt build-up at the end of the pipe to flow out.”
Good advice.
That thought triggered another. “When you install your pipe, don’t rest it on the bottom of the lake. Dig a sump around the end of the pipe or install it off the bottom. Silt will build up and can clog a pipe.”
His voice elevated a bit.
“Oh, here’s another thing. When you open a valve and water reaches maximum flow, close the valve slowly when you are ready to cut off the water. When water is really rolling and you shut the valve too fast, a “hammer-effect” occurs. Trying to stop fast-moving water too fast can create some serious issues.”
He told of a customer with a 12-inch siphon system with a butterfly valve on the downstream side. With full flow, the fellow turned off the valve too fast…water moving down the pipe stopped abruptly, but water rushing behind kept moving and blew out a joint of pipe, sending a flow of water on down, almost knocking the man off his feet. Then, he had to deal with a broken pipe. It’s akin to an escalator full of people and people at the bottom stop moving…soon there’s a clog…and that clog will keep moving, no matter what.
Close your valve slowly, once water is flowing fast. Pond pipes are designed for free-flow and no internal pressure.
An anti-vortex device on risers also minimizes the forces of water, too.
What else, oh gurus of all things pipe?
“Use primer and the proper glue on PVC pipe. Go heavy on the glue. Use the right glue on the right size pipe,” Johnson advised.
Johnson has some words of wisdom about risers. “Air inside a pipe, under water, wants to make the pipe float. Proper installation of a riser is important. Put the joints into the slope of the dam to minimize the risk of floating.”
Personally, I’ve seen some pretty big risers float when the lake filled. One, in particular, was a Volkswagen sized, welded riser that floated like a little boat, crimping the outflow pipe and causing problems when the lake first filled. The lake builder, a do-it-yourselfer, drained the lake, dug a hole under the riser, poured a concrete foundation with steel plates embedded in it and then welded his quarter-inch plate riser to the steel plates. Then, he poured about six inches of concrete into the bottom of the riser. It’s now like a little metal bomb shelter.
If your riser is built into the dam, don’t let the surrounding dirt erode away.
Johnson said, “I’ve seen several risers, 18-20 years into their lives, float.” Why? Because the surrounding soils act as the anchor. Remove the soils through erosion and the riser can eventually rise and become a problem.
Keith chimed in with another tip. “Make sure your pipe runs totally downhill. It sounds funny to say that, but I’ve seen more than one case where the contractor didn’t pay attention to the grades and the pipe didn’t layout as it should.”
Along those lines…always be sure your emergency spillway sits several inches higher than your pipe. Sounds simple, but it happens.
Another tip: “If you are debating on the size of pipe, know the size of your watershed and plan for the future. If the surrounding area is being developed, go larger on the pipe because the area around you may be covered in asphalt and concrete in the not-too-distant future and your pond pipe will need to accommodate much more water.”
There’s an important safety issue with pipes, too. I can speak from personal experience. If you have a clog in a pipe, and decide to unclog the pipe yourself, understand the forces of water. It is powerful stuff.
More than 30 years ago, I leased a fish farm. One three acre pond had a broken valve, so I cut a round piece of plywood to insert into the lip of the concrete drain pipe inside the pond, five feet deep on the bottom.
It worked to keep water in the pond.
Interesting design, built-in box for clean out.
But, later that summer, the water needed to be exchanged and I had no way to get water out. So, in the wisdom of youth, I simply decided to take a breath, squat under water and pull that board off the pipe.
Nope.
Went to the shop, got a crowbar and pried it open.
Slammed shut.
Testosterone kicked in. I wasn’t going to be defeated by a little piece of plywood. I took another breath, stuck the crowbar in the edge of that board and gave it a heave. It turned sideways and water roared out. So did my right leg.
Adrenaline kicked in.
So did my left leg. I was able to push free and extract myself. What seemed to be a simple task ended up being a big risk.
You might get sucked into or against a pipe if you unclog it.
People have died from that.
Be aware.
So, there you have it. A wide range of the best ideas to properly take care of your piping systems, preserving the life of your lake. I asked the guys to bring this story to a close?
Any parting words, fellas?
After summing up this string of great advice, maybe the best advice I heard from both those guys was, “Call for advice”.
That’s certainly a good call.
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