Hi FishinRod, thank you for your reply. My responses are below your questions which I copied below:
Did they core the whole dam, or just the gap that they had cut?
They cored the whole dam
How were they compacting the repaired core, especially at the top where it was steep? Were they wetting the clay while compacting?
They compacted with a skid steer and bucket. I did not see them wetting it.
I do like it that your pond only started leaking with the last 3-5 feet of water in the pond. That PROBABLY means your leak is shallow. However, it could still be a bottom leak. Sometimes the extra bit of hydrostatic pressure due to a higher water elevation can push water through tight material that otherwise does not leak.
This has crossed my mind, thank you for mentioning it.
If it is a shallow leak, then it is likely due to the breach repairs. However, there could be other causes. Do you currently have muskrats at the pond? Did the old pond have muskrat damages. Those b*astards can burrow back a long way into a dam. Water could be entering an old burrow and then working downwards beyond the core trench to exit at the toe of the dam. Likewise, some of the old tree roots in the dam could still be rotting out. They could create a water leak pathway similar to a muskrat burrow. Either would present as a shallow leak.
No current muskrats or signs of muskrats before the renovation. Old rotting roots is a possibility since the whole of the dam was not rebuilt.
Did the first bentonite treatment have a noticeable effect on the leak rate? Will you be able to tell if your second (larger) treatment does any good?
The first treatment did not seem to make a difference. Yes, I will be able to tell if the second treatment does any good. I've read that it may take up to 12 weeks, but I'm not sure that is accurate.
If the leak is not affecting your water level much, you might just leave it as is. Most leaks do NOT get better over time. However, one of the common exceptions is heavy clay soil. As the leak continues to hydrate more clay over a larger area, you may get enough swelling to reduce the leak further.
This is good to know. I'm not concerned much about the water level. Having the area behind the dam always wet and muddy is annoying. My biggest concern is the leak getting worse over time.
How deep is your pond at full pool? If you get an extended drought and your pond goes down 3', and the leak ceases at that point, then your fish are not really in much danger if your pond has sufficient depth.
At full pool the pond is 15' deep, so yes you are right; the fish would be ok.
I hope you enjoy your renovated pond ... despite the leak. It sounds like you paid good money to do it right the first time. It also sounds like your contractor got it 99% right, which is pretty good.
Thank you! I grew up with a farm pond and have waited 30 years to get back to the country and have a pond again. This contractor has done a lot of work for me: building site excavation, sewer line, water line, final grading, lagoon, septic and has treated me well. Worse comes to worse, I think I can get him to come back and try a repair.
Fingers crossed for your second bentonite treatment.
Ditto!
If that works a little bit, then came back and post some more. There is another product called Soilfloc that may work a little better if you are getting partial success with the bentonite.
I have researched the soilfloc a bit and the cost is prohibitive for me right now. The bentonite is costing me ~$10 per 50lb bag, but its still throwing good money away if it isn't doing any good.
Thanks again!
