Hi,
I am new to pond building (although I have seen quite a few being built) and am going to build a series of ponds (around 10) on our farm.
I have read "Just add Water" and have done a lot of research. My primary purposes are for retriever training (like John and Martha Russell in Mike's book), fishing and livestock.
My first build is a small sacrificial pond for learning purposes.
It has a bottom draw with an up pipe on the back side of the dike even with the water line. It also has a drain valve.
My concern on this pond is water doesn't seem to flow out of the overflow very well. It is overflowing at the emergency spillway and the overflow pipe. The pipe is small (3") but it doesn't come out of the top fast enough. If I open the drain valve, it rolls out great. Any suggestions?
Is the pipe strait (no high spots for air lock)? Does it slope downhill hard or is it level? How much freeboard between top of drain inlet and bottom of emergency spillway?
Straight up. It has a slope down hill. I think around 5-8 feet.
I am trying to upload some photos. When I try, it takes me to a donate page. Do I have to donate money to upload pictures?
Appreciated yes of course but the answer would be nope. Every pages has the donate button in the top right corner.
Is the pipe strait (no high spots for air lock)? Does it slope downhill hard or is it level? How much freeboard between top of drain inlet and bottom of emergency spillway?
Looking for clarification relative to your questions:
1. Should the pipe be straight?
2. Should it be level or slope? If it needs slope, how much per foot?
3. How much freeboard should it have?
Jeffrey,
When the pond is at full pool and water is ONLY coming out of the 3” pipe how much higher does the water in the pond need to come up (how many inches) until it goes over the emergency spillway?
Heppy
Pipe should be strait and the more sloped it is (greater the drop), the more water it will carry when full of water. The amount of freeboard that is needed depends on the watershed, rainfall amounts, pond size, pipe size, drop on pipe, pipe material, and length. There are formulas to size and design pond drains, dam height, and emergency spillways. I just over-engineer mine.
High spots in a drain pipe can cause an air lock. A 3" pipe is very small for most ponds. I have 4" drains on a few of my wetlands but will never go less than 6" on any new ones after having turtles plug the 4" ones several times. Even had a turtle plug a 6" drain. I now have guards on them all.
Jeffrey,
When the pond is at full pool and water is ONLY coming out of the 3” pipe how much higher does the water in the pond need to come up (how many inches) until it goes over the emergency spillway?
Heppy
Right now it is about 4 inches.
RAH: Thanks for the clarification. At first the pond was tiny. I was basically trying to calculate the water flow from the spring. During a rain the spring picked up extra flow from road runoff and the 3" wasn't adequate.
I made the pond bigger (it is around 3-4K sq. ft.) because the water flow was good. I plan on going with a 6 inch pipe.
When you talk about high spots in the drain pipe, are you referring to the horizontal portion in the dike?
If air can collect in a portion of the pipe then an air lock can form. I learned this the hard way in a small diameter gravity drain.
Only 4" of freeboard means the drain may never fully fill due to sucking air from the surface of the water. An anti-vortex device, like a hood, might help a little bit, but the pipe probably needs to be set lower.
RAH,
I'm struggling to understand why freeboard matters in my case. I can't see how it can suck air with a bottom draw.
Jeffrey,
Clicking on your links I only see the Google account sign in screen. A picture would help (“It has a bottom draw with an up pipe on the back side of the dike even with the water line. It also has a drain valve.”) to explain this to those reading your thread. The way I understand it is that your 3” overflow pipe runs through the bottom of the dam inside the pond and outside the back of the dam. From this point there is an upside down 90 degree T with the drain on the horizontal side of T furthest from the dam and a piece of 3” pipe sticking straight up in the air on the upside down vertical T on the backside of the dam. The height of the 3” pipe is 4 inches shy of being level with your emergency spillway when the pond is full. If this is correct what is the source of water for the pond (runoff, spring or stream fed). Do you know the size of your watershed or gallons per minute if it is spring or stream fed?
Heppy
I am no expert but I would think your head pressure in your drain pipe would be equal to the water depth. When your water goes up you have only 6 inches of head pressure, not very much.
You would need to replace with a syphon system if you have enough slope on the back side of your dam. Then a 3 inch pipe would pull a lot more water out.
Did not realize it is a bottom draw. The water pressure and flow rate are still dependent on the water level above the drain height. Only 4" of freeboard will produce slow flow. Put a small hole in the bottom of a bucket and watch the flow rate out of that hole as you fill the same bucket. The same is true if you start a siphon out of a bucket. As the water level goes down in the bucket, the speed of the water coming through the siphon decreases. If the vertical pipe hold immobile water on the downside of the dam during dry spells, what keeps it from freezing during cold weather? Or are your minimum temps too high?
Jeffrey,
Clicking on your links I only see the Google account sign in screen. A picture would help (“It has a bottom draw with an up pipe on the back side of the dike even with the water line. It also has a drain valve.”) to explain this to those reading your thread. The way I understand it is that your 3” overflow pipe runs through the bottom of the dam inside the pond and outside the back of the dam. From this point there is an upside down 90 degree T with the drain on the horizontal side of T furthest from the dam and a piece of 3” pipe sticking straight up in the air on the upside down vertical T on the backside of the dam. The height of the 3” pipe is 4 inches shy of being level with your emergency spillway when the pond is full. If this is correct what is the source of water for the pond (runoff, spring or stream fed). Do you know the size of your watershed or gallons per minute if it is spring or stream fed?
Heppy
I can't figure the picture thing out.
My 2 kids are IT professionals and suggested Imgur (free online photo storage). This has worked perfectly for me. The flying dog literally broke her neck and is in a brace for 8-12 weeks. Her muscularity is what saved her.
I use Imgur as well. Pretty simple
I am no expert but I would think your head pressure in your drain pipe would be equal to the water depth. When your water goes up you have only 6 inches of head pressure, not very much.
You would need to replace with a syphon system if you have enough slope on the back side of your dam. Then a 3 inch pipe would pull a lot more water out.
I love the siphon system, but it would get in the way of my dogs entering the water.
Yes I can see your pictures. What is your source of water and where in VA are you located? I’m no expert but RAH is asking you a great question about temperature. The pipe outside the dam is likely to get an ice plug and break if the water freezes and expands from what I understand.
Heppy
I'm in SW VA in the Blacksburg area. The water source is a spring. It runs about 10-15gpm (I'm guessing here based on a garden hose being about 6gpm) year round without rain. I can tell you the 3 inch over flow pipe works about at capacity when it isn't raining. When it rains hard I get at least double the flow. I am worried about freezing as well. I received advice not to worry about it but am hesitant.
DC70 posted something real interesting for a northern climate siphon system that is buried. It seems like it would meet my needs. I don't quite understand it though. Has anyone else built something like that?
It looks like you're emergency spillway is going over the top of the dam, if so you should move it to the undisturbed area, where the dam meets the hillside.
I'm in SW VA in the Blacksburg area. The water source is a spring. It runs about 10-15gpm (I'm guessing here based on a garden hose being about 6gpm) year round without rain. I can tell you the 3 inch over flow pipe works about at capacity when it isn't raining. When it rains hard I get at least double the flow. I am worried about freezing as well. I received advice not to worry about it but am hesitant.
Blacksburg definitely gets freezing conditions throughout the winter. I would assume the experts will tell you 3” pipe is undersized for the watershed. Most ponds that I have seen in VA have the overflow pipe buried in the dam with a T and the vertical pipe length setting the level of the pond with a trash rack on top to avoid clogging. This is what I decided to use on my pond as well as having a drain on the horizontal inside of the pond. I’m not saying that this is the only way by any means. DC70’s design is fantastic but I couldn’t find anyone around here who knew how to build it.
One tip that I can recommend is to lightly sand and paint the exposed portion of white pipe so it doesn’t degrade from ultraviolet light exposure.
On a separate note what kind of dog training do you plan on doing with all those ponds?
Heppy
I compete in Retriever Field Trials. I have Golden and Labrador Retrievers. My biggest reason for not wanting the overflow pipe at water level in the pond is my dogs might impale themselves when leaping in. They enter the water with reckless abandonment.
It looks like you're emergency spillway is going over the top of the dam, if so you should move it to the undisturbed area, where the dam meets the hillside.
You're right. When I figure out the overflow I will fine tune it.
I compete in Retriever Field Trials. I have Golden and Labrador Retrievers. My biggest reason for not wanting the overflow pipe at water level in the pond is my dogs might impale themselves when leaping in. They enter the water with reckless abandonment.
A trash rack should eliminate that concern. Just a thought.
Heppy
My 2 kids are IT professionals and suggested Imgur (free online photo storage). This has worked perfectly for me. The flying dog literally broke her neck and is in a brace for 8-12 weeks. Her muscularity is what saved her.
I believe it. Glad she is going to make it.
A trash rack should eliminate that concern. Just a thought.
Heppy [/quote]
I have seen dogs hit them. Crazy, but true.
My drain pipe is under a fixed dock. Best to also build a wire panel box around the drain pipe.