Pond Boss Forums INTRO Questions & Observations new member, old pond

Hi guys,
I really enjoy your site. May I trouble you all with a fewquestions? I have a small farm in NE Missouri with 2 ponds each less than 1 acre. The oldest of the two has about 5' of very fine and sticky grey silt in the bottom. During my first year the pond began to leak at a low spot 5' behind the dam. I could watch the water from the pond bubble out of a 2" hole after a large rain. Now the level has dropped a couple of feet from the base of the dam and I've discovered a half dozen muskrat tunnels. Of course, cattails took hold last year before I bought the place and are providing plenty of food for the diggers. I know that the muskrats and cattails must be eliminated, but how should I patch the holes in the dam? Does that leak I can see indicate that the pond is leaking from a point closer to the bottom (where all the silt is?)I relocated quite a few really nice bass and bluegill from the pond but a few remain. Should I drain it with a submersible pump before I proceed? A neighbor told me that the pond is 40+ years old and has been dredged and repaired in the distant past. I would really appreciate any comments or suggestions.
Thank You
JD

I'll let the experts respond, but if you meant 5 inches and not feet, I'd ask, could the grey silt possibly be bentonite from the former repair?

I probed the deepest portion with a long pole. That's where I got the 5 foot measurement. It looks like muck to me and the previous owner was tighter than bark on a tree with his money. Is it possible that all that goo is old bentonite?
Thanks,
JD

5 feet would be a HUGE amount of bentonite. The cost of which would be astounding. Most likely it is just silt and other organic matter. If it were my pond I would drain it and add a 18-24" layer of good clay to the face of the dam, clean out the "goo" and start over again.

Thanks for the advice. My neighbor has a backhoe I might be able to enlist after things have dried up.

Haw Creek,
You might be ahead to just go with a new pond if you have room upstream or downstream from this one.
Old ponds dry up on the surface, and some may dry out, but most stay quite saturated just below the surface.
Every pond and situation is different, but I would guess the mud will be 2 to 3 times as expensive to move as dirt. So moving the 5 foot of mud would cost as much as moving 10' or more of dirt, which would probably build a pond.
Good luck whatever you decide.

Thanks Kent, I have a 7 acre hayfield that adjoins this pond. There is a local contractor here who has a good reputation for building new ponds. The cost may be prohibitive, but a pond of 5 acres or so would be a dream come true.

haw creek,

I've experienced damage from nutria, which are similar to muskrats in that they build tunnels through the dam. I tried adding clay to the front side opening as someone suggested...didn't work, tried addding lots of clay to the backside, didn't work...didn't try bentonite because I didn't believe it would work...the fix was finally achieved this weekend by tearing out the tunnels and repacking the entire area. I found pine straw "rooms" many feet in both directions from the opening on the front and they extended all the way to the rear of the dam. None of this of course was evident from outside the dam.

It could be your situation is similar, maybe not. But after trying other things, it only took about 5 or 6 hours to dig all that out and repack with a small dozer. A permanent fix.