hello,
I have rencently posted about my 3/4 acre 50+ yr. old pond and that i was considering using a trash pump to get rid of the silt on the bottom. Well, after alot of thought and a great deal on the use of a D-6 dozer this fall, i think I am going to drain it and dig it out.
It is abut 4-6 ft. deep in the center and i would like to go deep as possible in the middle atleast, since we swim in it every day. My question is, exactly how dee can i go? Is there a point that the going so 15-20 ft. deep is not advisable? the pond seems to have a clay bottom. Any opinions would be appreciated.. Thanks,

It all depends on the "dirt" in the pond bottom. Sandy, loamy soils can't be dug as steep as clay.

In any case, if the water level will stay pretty constant, (not vary more than a foot or so) then I'd make the sides going down to the waterline between a 5:1 and 3:1 slope, 4:1 to 3:1 from waterline to 3'-4' depth, then once you get past 3'-4' water depth, increase it to 2:1. The size/shape of the pond will dictate how deep you can go.

The deeper you go the more $$ you will burn thru. If you are planning on aerating, I'd go as deep as you could, to have a place for the sediment/silt to go. In any case, I'd go at least 12' deep for as much of an area as the slope will allow. While that might not do you any good in the summer without aeration, your fish will love you during the winter months.

Thanks esshup,

I want to go atleast 12' if not more. So, as long as it stays clay while digging we are good to go right?
I have a creek that runs right by my pond and I can easily fll it with the creek. I use it alot to raise and lower the level of the pond. Getting rid of the silt is also not a problem ( over the hill it will go )
BTW-- no fish in the pond yet. Although this pond is very old, the fish went through the open drains and into the creek many years ago. i plan on re stocking once I dig it out.

Yep, as long as you have good clay, and it doesn't change for the worse once you dig, you're good.

what would be considered "changing for the worse"? Just so I know what to look for when we start digging.

I'm assuming that you did a test on the clay to see how impervious to water it is. If the clay changes consistency or color, see if you can do another test. I thought I had good clay, then it quickly turned into a clay/gravel mix, with higher % of gravel the more we dug. We ended up going thru 2 different aquafiers (layers of sand/gravel) in the clay. The pond ended up with almost a 4' variance of water level (from Spring to late Fall) due to hitting the aquafiers and not being able to pack them closed.

Nope, no test. Didn't know that was needed. This pond was made back in the early 60's by my grandfather just by digging it out with a dozer after he stripped the coal from the field.