Well, you made a good first step, get out and assess what you have. The next step is to have a good discussion with the pond co-owner about where the dos and don'ts are going to lie. Get on paper who owns what and who is allowed to do what. Who gets to fish, who gets to keep fish? What will be the mutual agreed upon plan to dredge or revamp the pond?
There are many good postings on the forum about those who bought a pond without sounding it and found it about half as deep as they were told during the real estate proceedings. This would be a marvelous time to turn lemons into lemonade. You could breach the dam, drain it down, let it dry and then create new contours, add structure, get rid of unwanted sediment and phosphorous, and have an awesome pond down the road.
Others choose to breach or partially breach the dam, drain down partially, dig and use the resulting dirt to redo the dam or to raise the height of the dam resulting in a deeper pond in the end along with the other benefits seen above.
others would dig a new pond next to this one and use the dirt to fill in the current pond (of course saving some of the area right adjacent to the new pond for forage or grow out ponds.
Some even divide this pond into 2 or even 3 smaller ones as many have found managing 2-3 smaller ones is way easier than 1 large (3 acre) pond.
this also may be a good time to talk to the co-owner about dividing into 'his pond' and your pond and add dirt to divide. For as long as you plan to live there it is going to be much more hassle free to have your own pond rather than a shared one.
Just my 2 cents.
keep us posted on your progress and post pictures.
