Need some advice on renovating a 1/4 acre pond on a property that boards dogs.
A little backstory:
We purchased a 15-acre property with a nice house and a big barn 20 years ago. At the time, there were two small ponds, one a runoff pond at the bottom of a steep incline on both sides. The other pond was simply overflow for the primary one. Both were full and thriving with frogs, turtles, and fish (?).
About 10 years ago, the secondary pond dried up, almost overnight. Then slowly the primary pond has been losing volume so that this year, even after huge snows and rainfall, you can see the bottom and the water is almost gone.
The pond is critical for the operation of the dog boarding business so I need to do something.
I have reached out to some locals who suggest I drain it, dredge it, find the source of the apparent leak, reline it with clay, and reroute water to it.
I am a total novice in this area. Does this sound correct? Advice? Pitfalls?
"I have reached out to some locals who suggest I drain it, dredge it, find the source of the apparent leak, reline it with clay, and reroute water to it."
Yes, that is usually the best advice.
(Except perhaps for the "dredge it". You can usually drain with a pump or siphon and let the pond dry - but that is a slow process. On larger ponds, the dam is usually breached to start the drying process. Sometimes "muck" is pushed out of the breach to speed the process and help the health of the pond.)
It would also be nice to know what caused the problem in the first place - so you don't spend a lot of money on your fix, and then have the leak occur again.
Existing ponds typically don't just dry up overnight.
Causes of leaks:
Around the time of the leak, did you ever observe any burrowing activity around the dams? Muskrats or beavers like to dig, and can cause leaks. For a small pond, I think dogs might even be able to burrow deep enough to cause a leak. When it gets really hot in my area, my dogs like to dig. They are certainly smart, because mine dig where the coolest, dampest soil exists in their yard. (Even though they are indoor/outdoor dogs!)
Another possibility is that the ground slumped or shifted on the backside of your dam, and that allowed the leak to get started. In that case, you may have only noticed a vertical crack or two near the top of the backside of the dam, or alternatively the slope farther down where the grass is mowed has slightly changed shape.
Finally, one of our worst offenders for leaks is trees on the dam. Do not let trees grow on your dam or pond embankments. Their roots always seek water. Often, the leak occurs after the tree has been felled or otherwise killed. As the roots decay, at some point the pathway for water gets opened up, and once the leak actually gets started, then it can drain a pond down overnight.
Please take a look around both of your ponds, and see if any of that matches, or if you observe some other potential cause. If you observe something that doesn't quite fit, come back with more info and you can get better advice than mine.
How deep were the two ponds? It doesn't take that much clay to get a good seal for shallower ponds.
If you do find a good contractor, they will probably have to perform the job in two steps. First, cut the dams for both ponds and let them dry, then come back and do the repairs. He might be able to do a little reconnaissance on your pond bottoms and seals while digging out the dams. That should enable the contractor to give you a pretty accurate bid to come back and do the bigger job of re-sealing the ponds.
If possible, it would help to divert the rainwater that would run back into the ponds during the "drying phase", but that might not be feasible?
If your ponds mostly stayed full during dry periods, then the leaks are your problem and you do not need to divert more water to the ponds. If your ponds were only half full part of the summer, then yes, it might help to divert some more surface water to the ponds. However, you do not want to divert too much. If too much, then a big rain can overwhelm your ponds and wash out your newly repaired dams.
I hope that helps you get started on your analysis, and helps to ask some questions of your contractor.
Good luck on your pond repairs! My dogs love their pond and creek swims!
I've had a few people come out and look and the best theory is that there's a crack in the bottom of the pond that facilitated the leaking. Our area is full of limestone rock and when wet creates karst which tends to be porous. I don't know much about rock, but this explanation seems the most plausible.
I've decided to just go ahead and drain it so we can see what's under there. As is, the "pond" is just a muddy mess and makes for dog play that creates work with all the cleaning up. Until I can get it to where dogs can jump in and swim, it's just a sinkhole.
Yes, encountering rock at the bottom of your pond basin can be a significant problem. That could even be the cause of the leak in a karst topography. Some rotten limestone below your pond may have collapsed just a bit further, and even a tiny cave in of material into the void could have ruptured that clay seal at the base of your pond.
Even without karst voids, rocks in the bottom of the pond make it more difficult to compact the clay seal. If your contractor does encounter some rocks, he may need to compact a few inches of extra clay in those areas to give a little safety margin to your seal.
Another option for a "cleaner" doggie pond, might be to use an artificial pond liner. (There are plenty of threads on that option on Pond Boss, or you can just do a regular internet search.)
If you have construction equipment on site to repair your ponds, digging a smaller dog pond of an easy shape to use an artificial liner would probably not add that much construction expense. It will add the expense of the actual liner, plus the costs to properly "pin" your liner to the adjacent ground.
You could even utilize water from your other ponds to keep the dog pond full. You could also build a "dock" for the dogs to jump into their pond. You also need to build a means to exit the water for dogs and "accidental" humans. A steep pond liner makes it difficult to get out of that type of pond.
The advice is sound. Once the pond is pumped dry, the pond can be "dredged" with a long stick excavator - one that has a 60' boom. They are used to clean ditches here. Once the junk has been cleaned out of the pond, bring in clay and spread it out 6"-8" MAX thickness. Then have a sheepsfoot roller drive over it multiple times to compact the clay, repeat the layer, repeat the rolling. You should get 18"-24" thick clay in 3 or 4 lifts that are compacted together with a sheepsfoot roller.
The tracks on the heavy equipment WILL NOT compact the clay enough.
The clay shouldn't be just on the bottom of the pond, it should come all the way up the sides to a point that is higher than the water will be in the pond.
If I wanted one side of the pond to have a deep dropoff, would the clay stick to the sides? Or would I need to reinforce with stone or cement? How does that work?
If I wanted one side of the pond to have a deep dropoff, would the clay stick to the sides? Or would I need to reinforce with stone or cement? How does that work?
Define steep. Steep edges are advised against due to erosion concerns.
Here's the latest. We have started to drain the pond and took a post hole digger and shovel to see how far we could dig before hitting clay (assuming there was some kind of liner).
Unfortunately we dug less than 6" and hit rock. Everywhere. For 15 years the pond was thriving but only in the last year has it leaked water so that now it's almost dry.
If I wanted one side of the pond to have a deep dropoff, would the clay stick to the sides? Or would I need to reinforce with stone or cement? How does that work?
Define steep. Steep edges are advised against due to erosion concerns.
If I wanted one side of the pond to have a deep dropoff, would the clay stick to the sides? Or would I need to reinforce with stone or cement? How does that work?
You will have a hard time getting clay to stay stable at steeper than a 2:1 slope. (1' drop for every 2' horizontal)
Here's the latest. We have started to drain the pond and took a post hole digger and shovel to see how far we could dig before hitting clay (assuming there was some kind of liner).
Unfortunately we dug less than 6" and hit rock. Everywhere. For 15 years the pond was thriving but only in the last year has it leaked water so that now it's almost dry.
What do we do now?
Scrape it out, then call TJ (teehjaeh57) here on the forum for the polymer product that he sells to seal leaks. It will find the places where the water is seeping out and plug it. Similar products are used in the fracking industry to make water tanks for their drilling operations where water is brought in via tanker truck.
